IPM Stratergies for Potato

Potato: Diseases and Symptoms Bacterial wilt Septoria leaf spot Late blight Early blight Common scab Black scurf/ canker V...

Potato: Diseases and Symptoms

1. Bacterial wilt
2. Septoria leaf spot
3. Late blight
4. Early blight
5. Common scab
6. Black scurf/ canker
7. Viral disease (potato virus X, S, & Y)
8. Potato Spindle Tuber Viroid (PSTVd)
9. Black leg and soft rot
10. Pink rot
11. Black heart- disorder
12. IPM for Potato

Bacterial wilt

Disease symptoms:

• In addition to the potato, the pathogen also damages plants such as chili, tomato, tobacco and egg plant, as well as several species of weeds.
• The symptoms of bacterial wilt infection can be seen on all parts of infected plants.
• Infected plant begins to wilt, starting from the tips of the leaves or where the stems branch out, and then spreading to all parts of the plant.
• Leaves become yellow at their bases, then the whole plant wilts and dies. When stems are cut a brown colored ring will be visible.
• When a tuber is cut in half, black or brown rings will, however, be visible. If left for a while or squeezed, these rings will exude a thick white fluid.
• A further symptom is fluid coming out of tuber eyes. This can be signified by soil sticking to tuber eyes when crops are harvested. Serious infection causes tubers to rot.

Survival and spread:

• Bacterial wilt pathogen can survive in soil (without a host for several seasons), water, seed tubers, potato plant remnants.
• The disease can spread from field to field or from plant to plant within field via infected seed, air, water, soil, farming tools, livestock and people.

Favourable conditions:

• High temperature, soil moisture, low pH.
• The disease spread rapidly in the warmer temperatures in storage areas. Infected seed can also be a source of the disease in the field.

Septoria leaf spot

Disease symptoms:

• Less vigorous plants are usually affected
• Small, round to irregular spots with a grey center and dark margin on leaves
• Spots usually start on lower leaves and gradually advance upwards
• At later stage spots coalesce and leaves are blighted
• Complete defoliation of affected leaves may take place.
• Stems and flowers are sometimes attacked
• Fruits are rarely attacked

Survival and spread:

• Primary: Mycelium or conidia found in pycnidia in infected plant debris or on solanaceous weeds
• Secondary: Conidia spread through rain splash or wind and also by slimy conidia sticking on to hands and clothing of potato pickers.

Favourable conditions:

• Poor vigour of plants due to nutrient deficiency in late season
• High humidity or persistent dew at 25 ºC
• Moist weather with intermittent showers.

Late blight

Disease symptoms:

• This disease damages leaves, stems and tubers. Affected leaves appear blistered as if scalded by hot water and eventually rot and dry out.
• When drying out, leaves turn brown or black in color. When infections are still active, spots appear on the underside of leaves blanketed in what looks like flour.
• Affected stems begin to blacken from their tips, and eventually dry out.
• Severe infections cause all foliage to rot, dry out and fall to the ground, stems to dry out and plants to die.
• Affected tubers display dry brown-colored spots on their skins and flesh. This disease acts very quickly. If it is not controlled, infected plants will die within two or three days.

Survival and spread:

• The pathogen survives in plant debris in the soil.
• It spreads through soil and infected seed tubers.

Favourable condition:

• High humidity
• Low temperature and leaf wetness

Early blight

Disease symptoms:

• This is a common disease of potato occurring on the foliage at any stage of the growth and causes characteristic leaf spots and blight.
• Normally the disease symptoms become apparent during tuber bulking stage and develop leading to the harvest.
• The early blight is first observed on the plants as small, black lesions mostly on the older foliage.
• Spots enlarge, and by the time they are one-fourth inch in diameter or larger, concentric rings in a bull's eye pattern can be seen in the center of the diseased area.
• Tissue surrounding the spots may turn yellow. If high temperature and humidity occur at this time, much of the foliage is killed.
• Lesions on the stems are similar to those on leaves, sometimes girdling the plant if they occur near the soil line.

Survival and spread:

• Primary: The pathogen overwinters in infected plant debris in or on the soil where it can survive at least one and perhaps several years. It can also be seed borne.
• Secondary: The spores are transported by water, wind, insects, other animals including man, and machinery.

Favourable conditions:

• Warm, rainy and wet weather

Common scab

Disease symptoms:

• Pathogen infects young developing tubers through the lenticels and occasionally through wounds.
• Symptoms of common potato scab are quite variable and are manifested on the surface of the potato tuber. The disease forms several types of cork-like lesions including surface.
• Damaged tubers have rough, cracked skin, with scab-like spots. Severe infections leave potato skins covered with rough black welts.
• Initial infections result in superficial reddish-brown spots on the surface of tubers. As the tubers grow, lesions expand, becoming corky and necrotic.

Survival and spread:

• Pathogen can survive in soil, uncomposted manure or seed
• It spreads through contaminated soil, seed and water.

Favourable conditions:

• Disease is common in fields with low soil pH favoured by high soil moisture. Disease problems may be aggravated by excessive irrigation.

Black scurf/ canker

Disease symptoms:

• Rhizoctonia canker occurs when stolons contact soil borne fungal bodies.
• Pathogen infects plant tissue and causes stolon blinding thus reducing tuber production and yield.
• It also infects tubers causing black scurf but this is purely cosmetic, reduces tuber appearance and does not reduce yield.

Survival and spread:

• Pathogen is soil and seed borne, remain in soil and plant debris including infected tubers

Favourable conditions:

• High temperature and moisture is the favourable for disease development

Viral disease (potato virus X, S, & Y)

Disease symptoms:

• Potato virus Y (PVY ) is a Potyvirus, causes stipple streak. The necrotic strain generally causes mild foliage symptoms, but necrosis in the leaves of susceptible potato varieties.
• Potato virus S (PVS) is a Carlavirus, if plant infected early in the season, show a slight deepening of the veins, rough leaves, more open growth, mild mottling, bronzing, or tiny necrotic spots on the leaves. PVS is transmitted by aphids non-persistently.
• Potato virus X (PVX) is the type member of the Potyvirus family of plant viruses. Plants often do not exhibit symptoms, but the virus can cause symptoms of chlorosis, mosaic, decreased leaf size, and necrotic lesions in tubers.
• PVX can interact with PVY and PVS to cause more severe symptoms and yield loss than either virus alone. The source of this virus is infected tubers.

Survival and spread:

• PVY is mechanical and aphid transmitted
• PVS is transmitted by aphids, including Myzus persicae, the green peach aphid. It is also mechanically transmissible, and transmissible through tubers.
• PVX is transmitted mechanically, not by an insect vector. Tobacco, pepper, and tomato can also serve as hosts of PVX.

Potato Spindle Tuber Viroid (PSTVd)

Disease symptoms:

• It causes mild foliar symptoms including smaller leaves that curl downward, giving the plant a more upright growth habit. Plants can also be stunted, and leaves can be grey and distorted.
• The stems are often more branched, with the branches having sharp angles on the stem.
• Tubers become narrow and spindle or oblong in shape, or more rounded than expected for a particular variety, and have prominent eyebrows.
• Tubers can also become cracked or develop knobs and swellings.

Survival and spread:

• The PSTVd often transmitted mechanically, as well as through pollen and true seed.
• PSTVd can also infect tomato and nightshade.

Black leg and soft rot

Disease symptoms:

• Black leg is a rot of the lower stem region. This is encouraged by cool, damp conditions.
• Soft rot occurs when the bacteria gains access to the tuber through wounds & other entry points.
• Symptom can range from cultivator damage to fungal lesions.
• The bacteria dissolve the cell walls and liquefy the tuber invards. No distinct smell is present in true soft rot.

Survival and spread:

• The introduction of bacteria is always through a wound in the plant tissue. It can reside in plant residue for short periods. The pathogen may spread through the soil water and infected seed.

Favourable conditions:

• Disease is encouraged by cool, humid conditions.

Pink rot

Disease symptoms:

• Foliar symptoms of underground infections include wilting and chlorosis.
• Tubers become infected through diseased stolons and show darkened diseased area on the skin.
• The rotted tissues remain firm and become slightly spongy.
• If the tuber is cut the tissue oxidizes to a pinkish tinge, an easy diagnostic characteristic.

Survival and spread:

• Soil and seed borne.

Favourable conditions:

• High soil moisture and cool condition increase disease incidence.

Black heart- disorder

Disease symptoms:

• Black heart occurs primarily in storage when the tubers do not receive enough oxygen.
• Blackening of the tuber center follows acute oxygen deficiency associated with either low temperature in confined storage or high field soil temperatures
• The tissue dies from the inside out and turns jet black. Smell is absent.
• Affected tubers rot later.

IPM for Potato

To know the IPM practices for Potato, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3.02   

 

167 ratings

Potato Pests

1. Pests of National Significance
1. Insect pests
2. Nematode
3. Diseases
4. Weeds
1. Kharif
2. Broadleaf
3. Grasses
4. Sedges
5. Rabi
6. Broadleaf
7. Grasses
8. Rodent and non-rodent vertebrate pests
5. Pests of Regional Significance
1. Insect and mite pests
2. Diseases
3. Nematodes
4. Rodent
6. IPM for Potato

Pests of National Significance

Insect pests

• Aphids: Myzus persicae Sulzerand, Aphis gossypii Glover (Hemiptera: Aphididae)
• Potato tuber moth: Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae)
• Jassids/ leaf hoppers: Amrasca devastans Dist. and Empoasca fabae Harris (Hemiptera: Cicadellidae)
• Whitefly: Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae)

Nematode

• Root-knot nematode: Meloidogyne sp.

Diseases

• Late blight: Phytophthora infestans (Mont.) de Bary
• Black scurf: Rhizoctonia solani J.G. Kühn
• Leaf spot complex: Alternaria sp, Phoma sp.
• Septoria leaf spot: Septoria lycopersici var. malagutii Ciccarone & Boerema
• Early blight: Alterneria solani Sorauer
• Common scab: Streptomyces scabies Lambert and Loria
• Bacterial wilt: Ralstonia solanacearum Smith
• Viral diseases : (Potato virus X, S, Y and Potato leaf roll virus)

Weeds

Kharif

Broadleaf

• Pigweed: Amaranthus viridis Hook. F. (Amaranthaceae)
• Swine cress: Coronopus didymus (L.) Sm. (Brassicaceae)
• Black nightshade: Solanum nigrum L. (Solanaceae)
• Common purselane: Portulaca oleracea L. (Portulacaceae)
• False amaranth: Digera arvensis Forsk. (Amaranthaceae)

Grasses

• Rabbit/ crow foot grass: Dactyloctenium aegyptium (L.) Beauv. (Poaceae)
• Crabgrass: Digiteria sanguinalis (L.) Willd. (Poaceae)
• Barnyard grass: Echinochloa crusgalli (L.) Beauv. (Poaceae)

Sedges

• Purple nutsedge: Cyperus rotundus L. (Cyperaceae)
• Flat sedge: Cyperus iria L. (Cyperaceae)

Rabi

Broadleaf

• Lamb’s quarter: Chenopodium album L. (Chenopodiaceae)
• Scarlet pimpernel: Anagallis arvensis L. (Primulaceae)
• Sweet clover: Melilotus indica (L.) All. (Fabaceae)
• Fine leaf fumitory: Fumaria parviflora Lam. (Fumariaceae)
• Corn spurry: Spergula arvensis L. (Caryophyllaceae)
• Goat weed: Ageratum conyzoides L. (Asteraceae)
• Rough medic: Medicago denticulata Willd (Fabaceae)
• Broad leaf wood sorrel: Oxalis latifolia Kunth. (Oxalidaceae)
• Horse purslane: Trianthema portulacastrum L. (Aizoaceae)
• Onion weed: Asphodelus tenuifolius Cav. (Liliaceae)
• Field bindweed: Convolvulus arvensis L. (Convolvulaceae)

Grasses

• Blue grass: Poa annua L. (Poaceae)
• Canary grass: Phalaris minor Retz. (Poaceae)

Rodent and non-rodent vertebrate pests

• Lesser bandicoot: Bandicota bengalensis
• Indian creased porcupine: Hystrix indica
• Wild boar: Sus scrofa

Pests of Regional Significance

Insect and mite pests

• Cut worm: Agrotis segetum Denis & Schiffer müller (Lepidoptera: Noctuidae) (Tripura, Gujarat, Himachal Pradesh)
• White grub: Lachnosterna longipennis Blanchard and L. coracea (Coleoptera: Scarabaeidae)(Himachal Pradesh, Uttar Pradesh)
• Leafminer: Liriomyza huidobrensi Blanchard (Diptera: Agromyzidae)
• Spider mites: Polyphagotarsonemus latus Banks (Acarina: Tarsonemidae) (Maharashtra, Karnataka, Orissa)
• Thrips: Thrips sp (Hemiptera: Aphididae) (Orissa)
• Tobacco caterpillar: Spodoptera litura Fabricius (Lepidoptera: Noctuidae) (Uttar Pradesh, Karnataka)
• Leaf eating caterpillar/gram pod borer: Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) (Punjab, Haryana, Himanchal Pradesh)
• Semi looper: Trichoplusia ni Hübner (Lepidoptera: Noctuidae) (Haryana, Himanchal Pradesh)

Diseases

• Potato spotted wilt virus (Karnataka)
• Charcoal rot: Macrophomina phaseolina (Tassi) Goid. (Himachal Pradesh, Delhi, Bihar, Madhya Pradesh, Assam, Central provinces, Punjab, Uttar Pradesh)
• Potato spindle tuber viroid (PSTVd) (Himachal Pradesh, Bihar)
• Pink rot: Phytophthora erythroseptica Pethybr. (Himachal Pradesh)
• Soft rot: Erwinia carotovora Winslow (Delhi)
• Black heart (disorder): Acute oxygen deficiency

Nematodes

• Golden nematode: Globodera rostochinensis (Wollenweber) (Tamil Nadu)
• Potato cyst nematode: Globodera pallida (Stone) (Tamil Nadu, Kerala)

Rodent

• Indian porcupine: Hystrix indica Kerr

IPM for Potato

To know the IPM practices for Potato, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3.05   

Management options for white grub in apple and potato

1. Introduction
2. Management of Adult beetles
3. Management of grubs or larval stage
4. Target weak link of insect life cycle
5. Cultural Management
6. Biological control
7. Integrated Pest Management (IPM)

Introduction

Brahmina (Lachnosterna, Holotrichia) (Hope) 1839 (Coleoptera: Scarabaeidae: Melolonthinae) is a cosmopolitan genus with 127 known species worldwide. Among these, Brahmina coriacea (Hope) 1839 has been recorded from most of the northwestern Indian hills, occupying Himachal Pradesh (Chander et al., 1995); Uttarakhand (Singh et al., 2003; Dixit and Sharma, 2010) and Jammu and Kashmir (Bhat et al., 2005). The species has also been notified in Nepal (Thapa 2000; Ahrens, 2005) and Pakistan (Zahoor et al., 2003; Ratcliffe and Zubair, 2010). Being polyphagous, B. coriacea causes huge economic losses to large number of crops.

In hills of Shimla, Himachal Pradesh, B. coriacea constitutes 90% of total beetle population in apple orchards (Mehta et al., 2010; Pathania, 2014). It is highly polyphagous feed voraciously on variety of host plants (fruits/forest trees, their nurseries, vegetables, lawns and various field crops) in different part of country (Gupta et al., 1977; Chandel et al., 1994; Kumar et al., 2007). Chander and Singh (1985) reported the beetle as the major insect pest of potato and apple in higher hills.

Adult of the beetle after emergence in June, July feed on foliage of apple wild rose, walnut, apricot, Robinia and polygonum etc. of while grubs feed on roots and tubers. Third instar grubs are reported to cause maximum yield loss (Sharma and Bhalla, 1964). High economic loss and different feeding behavior of adult beetles and grubs necessitates integration of different tools viz., mechanical, chemical, cultural etc. for effective management of this pest (Singh et al., 2002).

Management of Adult beetles

Unlike other white grub species, whose adults mainly feed on wild crop, adult of B. coriacea feed on foliage of economically important crops like apple and potato which makes its management very crucial. Aggregation behavior of adult beetles on host foliage during night time can be effectively exploited to kill them by spraying foliage with insecticide.

Chemical control options recommended to farmers include spraying methyl parathion, carbaryl or monocrotophos (Chandel et al. 1994b; Chandla et al. 1988; Anonymous 2000) but these insecticide are going to be banned or going to be phased out. Dimethoate has been found to be extremely effective in potato in Himachal Pradesh (Anonymous, 2002). Chlorpyriphos 20EC @ 400g a.i/ha after mixing it with the sand should be applied at the time of first earthing up operation in potato crops (All India Project on Soil Arthropods pests). But care should be taken that there should be enough moisture in the soil so that it is translocated sufficiently to root zone where insect is actually present. 

Manual collection of adult beetles during time of emergence and destruction helps in reducing egg laying and further population built up. Use of most preferred host as attractant crop or trap crop could be one of cultural method to control B. coricea (Veeresh, 1977). At Fagu in the Shimla, Himachal Pradesh, about one lakh beetles were collected using attractant crops like apple, apricot etc. and killed in an endemic area of about 20 ha of potato fields, and the pest was managed within 3 years of operation (Anonymous, 2004).

Management of grubs or larval stage

White grubs typically are controlled by applying a soil insecticide. During the 1970s and 1980s, long residual chlorinated insecticides like aldrin, DDT and heptachlor dusts were used for grub control (Singh, 1964; Pushkarnath, 1966; Rataul and Misra, 1979) but these fast-acting, persistent insecticides were restricted or banned for agricultural usage during the 1990s in response to the environmental concerns and the food safety. Currently among insecticides chlorpyriphos, phorate and carbofuran are widely used in potato.

Chandla et al. (1988) reported that the grubs of B. coriacea in potato fields can be controlled effectively by application of phorate 10G or carbofuran 3G at 2.5–3.0 kg a.i./ha in furrows at the time of planting but use of phorate is recently banned by Government of India. In mid-hills of Himachal Pradesh, soil drenching with chlorpyriphos at 5 kg a.i. /ha has been found to be effective resulting in 83.30–100.00% mortality of eggs and grubs of B. coriacea (Chandel et al.,1993). Further, Sharma and Chandla (2013) reported that combination of phorate 10G at 10 kg/ha at planting followed by spray of chlorpyriphos (0.1%) on ridges at earthing up in June resulted in 90% reduction in tuber damage. Recently studies in Shimla concluded that clothianidin 50 WDG to be more effective at a very low dose (120 g a.i./ha) than conventional granular insecticides like phorate and carbofuran. Chandel et al. (2008) dip treated seed size tubers in insecticide solution for 30 min and observed 80.1–93.6% control of B. coriacea grubs with chlorpyriphos (0.1%) and imidacloprid (0.05%).

Target weak link of insect life cycle

Weak links in insect life cycle is the time when particular insect stage is more susceptible to insecticides and other control strategies. Missing the appropriate treatment window can lead to little or no insect control. To obtain the best results, insecticide application should occur soon after adult emergence and should coincide with egg laying or egg hatching (Chandel et al., 2008). If the field has a history of whitegrub problem, a preventive treatment may be the best approach. Applying the preventive insecticide around the third week in June will have the insecticide in place when eggs begin to hatch.

Cultural Management

There are certain cultural practices which are highly effective in suppressing whitegrubs. Chandel and Kashyap (1997) suggested that the best way to clean grubs out of a field is to pasture the land with pigs, as when pigs are allowed to forage on heavily infested land, they will usually root out and eat the grubs.

Crop rotation in potato with crops like clover and alfalfa reduce the B. coriacea population because of the fact that adults do not deposit eggs in clover and alfalfa unless there is a considerable admixture of grasses or other weeds (Chandel and Chandla, 2003).

In the summer crop of potato, especially in hilly states, the most critical period in the dynamics of the whitegrub infestation lies between August and September and timely harvest can avoid huge losses.

Biological control

Whitegrubs are naturally infested by various entomopathogenic fungi. Metarhizium anisopliae (Metsch.) and Beauveria bassiana (Bals.) when tested in combination with insecticides are reducing the whitegrubs population considerably in potato in Himachal Pradesh (Chandel and Mehta, 2005). Pathogenicity of M. anisopliae and B. bassiana is affected by soil temperature and water content. Infected beetles do not die for several days, so there is potential for auto-dissemination within populations.

Many entomopathogenic nematodes genera like Steinernema carpocapsae (Weiser), Steinernema feltiae (Filipjev), Heterorhabditis indica Poinar and Heterorhabditis bacteriophora Poinar can be effective biocontrol agents for controlling whitegrubs in potato. Soni et al. (2018) reported that Beauveria brongniartii (Saccardo) is considerably effective in managing this voracious pest because this particular species is native to the region and so sustain well in soil. They also found out that method of treatment (dip and oral feeding) did not affect susceptibility of B. brongniartii in different instars of B. coriacea, but the susceptibility of younger instars was marginally higher than older instars. Chandel et al. (2005) observed less B. coriacea grubs in H. indica-treated potato fields in Shimla. The efficacy of nematodes for grub control may be enhanced by using them in combination with certain insecticides. H. indica interacts synergistically with imidacloprid. Sluggishness of imidacloprid-treated grubs facilitates host attachment and subsequent penetration of infective juvenile nematodes.

Several species of predatory birds prey upon both the grubs as well as beetles. Amongst the avian predators, Indian myna (Acridotheres tristis L.) and jungle crow (Corvus macrorhynchos Wagler) are the major predators feeding on whitegrubs at the time of ploughing (Singh et al., 2003). Spotted owlet (Athene brama) settles on walnut trees during night and preys upon beetles (Mishra 2001a). These important predatory birds need to be conserved in the potato ecosystem and be exploited using appropriate management practices.

Integrated Pest Management (IPM)

As stated above integration of different pest management tools is crucial as individual efforts may not be very successful. Hence IPM practices for management of this pest can be as follows:

1. Collection and Destruction of Adult Beetles: The adult emergence is synchronous; thus, the collection and killing of beetles have been found to be one of the most effective techniques. This large scale beetle collection technique is cost effective and area wide mass campaign is effective in endemic area. Light trap, though a tool for population monitoring, can be used in reducing the population for this strongly phototactic species.
2. Spraying Insecticides on the host Trees: As like most of scarab beetle, B. coriacea after emergence congregate on preferred host plant for mating and feeding. These beetles can be conveniently killed by spraying the trees with insecticides. The beetles which settle on treated hosts would be killed before they return to the soil the next morning for egg laying.
3. Exposing grubs of beetle: Fields having a history of whitegrub attack should be tilled several times in April–May or in September. Tilling or discing soil macerates grubs and exposes them to predators such as birds.
4. Use of Soil Insecticides: The insecticides should be applied in endemic localities to bring down the population below the economic threshold level. The most effective insecticides are chlorpyriphos or phorate and are recommended for soil application against neonate tiny grubs. The older grubs are hard to control as they move deep into the soil, and the insecticides usually do not penetrate the soil well enough to kill the grubs.
5. Biological Control: Entomopathogenic fungi and nematodes can effectively combat the infestation of whitegrubs. Entomopathogenic fungi include M. anisopliae and B. bassiana, and usually, the fungi are used in combination with farm yard manure. The strains of nematodes which are available for field application are S. carpocapsae, S. feltiae, H. indica and H. bacteriophora but care should be taken that soil must be well soaked before applying nematodes as they need water for transport down to the root system.

Content authors : Niraj Guleria and Suresh M Nebapure, Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi 110 012, India.
Corresponding author E-mail: smnebapure@gmail.com

 

5   

 

4 ratings

Potato: Insect, Mite and Nematode Pests Management

1. Aphid
2. Leaf miner
3. Whitefly
4. Spider mites
5. Thrips
6. Jassid / leaf hopper
7. Potato tuber moth
8. Potato cutworm
9. Tobacco caterpillar
10. Leaf eating caterpillar / gram pod borer
11. White grub / root grub
12. Root-knot nematode & cyst nematode
13. IPM for Potato

Aphid

Biology:

• Aphids reproduce in two ways: by laying eggs and giving birth to young ones. Which birth process is used depends on environmental conditions and the availability of food.
• When food is plentiful, aphids give birth to live young. Populations develop quickly as this pest has many young ones, a short lifespan and pre-adult insects can also give birth.
• Eggs hatch after three or four days. Young aphids, called nymphs, need five to eight days to become adults

Damage symptoms:

• Direct damage: Aphids damage plants by puncturing them and sucking their juices. They damage the young and soft parts of plants, such as new leaves and shoots. Signs of damage are leaves not opening properly and being smaller in size. Severe infestation can cause shoots to wilt and dry out.
• Indirect damage: Aphids have wings and can move from plant to plant spreading viral diseases, picked up from infected plants. Aphids secrete a sugary liquid that stimulates black sooty mold growth. It can cover the surface of leaves which affects the way they absorb sunlight.

Favorable conditions:

• A relative humidity of 66 + 2.8% and 11 – 14⁰C temperature are ideal for development of this aphid.
• Its population sharply decreases with increase in RH over 73 percent.

Natural enemies of aphid:

• Parasitoids: Lysiphlebus sp, Diaeretiella sp., Aphelinus sp., Aphidius colemani etc.
• Predators: Ladybird beetle, lacewing, spider, hover fly etc.

Leaf miner

Biology:

It was introduced into India through Chrysanthemum cuttings.

• Egg: Eggs are laid inside leaves, they are very small and clear in color. Larvae hatch after about 2 - 3 days.
• Larva: Larvae remain inside leaves. They are very small and have no legs so cannot move from one leaf to another. The larval stage lasts around 6-12 days. Full grown larvae measure 3 mm.
• Pupa: These are formed in the ground or inside leaves. On potato plants, pupae usually fall to the ground. The pupal stage lasts around 14-16 days. Pupation takes place inside a thin loose mesh of silken cocoon.
• Adult: These are extremely small at 2-4 mm in length, black in color with two yellow spots on their backs, measuring 1.5 mm in length. They are most active in the morning from 7:00 to 9:00 and in the afternoon from 16:00 to 18:00. Adult flies produce an average of 166 eggs per female. They are attracted to the color yellow. The female fly punctures upper surface of leaf to lay eggs singly. The egg hatches in 4 days. Total life cycle takes 3 weeks. Generally it does not cause economic damage.

Damage symptoms:

• The leaf miner flies damage plants during its larval and adult stages mainly on the lower third of plants.
• Larvae begin eating the insides of leaves immediately after hatching, and bore mines inside them.
• In instances of severe infestation, all that is left of leaves is their upper and lower skins.
• Affected leaves become dry and drop off the plant.
• Adult flies puncture holes in leaves in order to lay eggs and feed on plant juices.

Natural enemies of leaf miner:

• Parasitoids: Chrysocharis pentheus , Gronotoma micromorpha, Diglyphus isaea etc.
• Predators: Lacewing, ladybird beetle, spider, red ant etc.

Whitefly

Biology:

• Egg: The female whiteflies lay eggs singly on the underside of the leaves. Eggs are smooth, sub elliptical, stalked, and broader at basal end. Its colour is light yellow, when freshly laid, turn dark brown later on. The eggs hatch in 5-17 days. Stalked nymph: It is louse like, sluggish creature having pale-yellow body. The nymphal stage lasts 14 to 81 days.
• Pupa: Convex in shape and possesses deep yellow patches on the abdomen.
• Adult: In 2-8 days, the pupae change into white flies. Adult fly is small winged insect having light yellow body of 1.0-1.5 mm length dusted with a white waxy powder. Wings are pure white and have prominent long legs. The life cycle is completed in 14-122 days. Eleven generations of this pest are completed in a year.

Damage symptoms:

• Chlorotic spots
• Yellowing
• Downward curling and drying of leaves.
• Vector of potato leaf curl disease

Favorable conditions:

• The temperature of 28-36 ⁰C and 62-92% relative humidity and scanty rainfall during August to January are quite favorable for this pest.

Natural enemies of whitefly:

• Parasitoid: Encarsia formosa, Eretmocerus spp. etc.
• Predators: Ladybird beetle, lacewing, spider, hover fly, reduviid bug, robber fly etc.

Spider mites

Biology:

• Egg: Eggs are hyaline, globular laid in mass
• Nymph: Yellowish in colour
• Adult: Red coloured small size

Damage symptoms:

• Affected leaves become reddish brown and bronzy
• Under severe infestation larvae construct silken webbing on the leaves
• Leaves wither and dry
• Flower and fruit formation affected

Natural enemies of spider mite:

• Predators: Predatory mites, predatory thrips, Oligota spp., Orius spp., anthocorid bugs, hover flies, mired bug etc.

Thrips

Biology:

Thrips are very small, have elongated abdomens and are yellowish or blackish in color. Although the adults have wings, these insect pests do not usually fly. They are often found on potato plants throughout all growth stages, from sprout development to tuber maturation. Thrips reproduce by laying eggs. Nymphs emerge from the eggs. It takes between 7 and 12 days to develop from eggs into adult thrips.

Damage symptoms:

As with aphids, thrips also cause direct and indirect damage:

• Direct damage: Thrips damage the undersides of leaves by sucking their juices. They damage young and soft parts of plants such as new leaves and shoots. As a result, leaves curl downwards and change to a blackish silver color. Severe infestation causes young leaves to wilt and dry out.
• Indirect damage: Thrips can carry and spread viral diseases.

Natural enemies of thrips:

• Parasitoids: Ceranisus menes
• Predators: Predatory thrips, minute piratebug, lacewing etc.

Jassid / leaf hopper

Biology:

• Egg: Elongated yellow-white eggs are deposited in leaf vein. It becomes greyish yellow before hatching. The female jassids lay about 15 eggs on the underside of leaves embedding them into leaf veins. The eggs hatch in 4-11 days.
• Nymph: Nymphs are pale – green, wedge shaped and their wing pads extend up to the fifth abdominal segment. The nymphal stage is complete in 7-21 days.
• Adult: It is a wedge shaped and pale green insect of about 3.5 to 5mm length having a black spot on each transparent forewing. It turns reddish brown during winter. Winged adults live for 35-50 days. This pest completes seven generations in a year.

Damage symptoms:

• Both nymphs and adults of Jassids suck plant sap as a result of their severe attack, the leaves curl; turn pale, bronze and dry up.

Favorable conditions:

• Temperature 27 to 36⁰ C and relative humidity below 75% favors the multiplication of Jassid.

Natural enemies of leaf hopper:

• Parasitoids: Anagrus flaveolus, Stethynium triclavatum etc.
• Predators: Lacewing, red ant, mirid bug, big-eyed bug, ladybird beetle etc.

Potato tuber moth

Biology:

• Eggs: The eggs are oval and measure less than 1mm in diameter. The female moth lays eggs on the underside of leaves or on exposed tubers near the eye. Each female can lay 150-200 eggs. Incubation period is 3-7 days.
• Larva: Newly emerged larvae are gray, yellowish white with brown head. Larval period is 15-20 days.
• Pupa: Full grown caterpillars come out of the tubers/ foliage and pupate in silken cocoons either in dried leaves, soils, over the stored tubers or in cracks and crevices in the store. Pupal period lasts for 11-12 days.
• Adult: It is a small grayish brown moth. Total life cycle is completed in 20-30 days at optimum conditions of 22-28⁰C temperature and 60-70% relative humidity. There are 8-9 overlapping generations in a year.

Damage symptoms:

• Potato tuber moths affect both tubers and foliage.
• Larvae eat their way inside tubers either in the field or the storage area.
• Severe infestation generally occurs in storage causing irregular galleries and 'tunnels' deep inside the tube.
• Larvae feces can be seen near bore holes.
• On foliage, larvae attack the stems and leaves of potato plants.
• They enter leaves, eat the inside and leave only a dried up outer skin.
• Severe infestation occurs in same areas, but yield loss is generally limited.

Natural enemies of potato tuber moth:

• Parasitoids: Chelonus blackburni, Copidosoma koehleri, Trichogramma spp., Apanteles sp., Pristomerus vulnerator etc.
• Predators: Lacewing, red ant, ladybird beetle, spider, robber fly, dragonfly etc.

Potato cutworm

Biology:

Cutworms damage potato plants, and affect almost all types of plants including weeds. Cutworms reproduce by laying eggs. Their life cycle includes eggs, larvae, pupae and moths. It takes up to 36 days for them to develop from eggs to adult insects. The various stages display the following characteristics:

• Egg: Eggs are creamy white, dome-shaped laid on the surface of the soil, but are very difficult to see. Each female moths come out at dusk and lay eggs (200-350) in clusters of about 30 each, either on the under surface of the leaves of host plants or in the soil.
• Larva: Newly emerged young larva is yellow or blackish- green in colour, 1.5 mm long with a shiny, black head and a black shield on the prothorax. The full-grown larva is about 42-45 mm long and is dark or dark brown with a plump and greasy body and lives in the soil. They have striped markings running down the sides of their bodies. The larval stage varies from 30-34 days,
• Pupa: Pupae are brown to dark brown, about 1.5 to 2.0 cm in length and are usually found in or on piles of leaf mould. Pupation takes place underground in an earthen chamber is completed in 10 to 30 days
• Adult: It measures about 25 mm from the head to the tip of the abdomen and looks dark with some grayish patches on the back and dark streaks on the forewings. Adults live for 7-10 days. The moths usually emerge at night. The life cycle is completed in 48 to 77 days. This pest generally completes three generations in a year.

Damage symptoms:

• These pests damage plants and tubers during dark.
• They attack young plants by severing their stems, pulling all parts of the plant into the ground and devouring them.
• Plants with severed stems have difficulty growing again.
• This pest can cause serious damage; particularly when crops are at 25 – 35 days after planting. Signs of damage on tubers are boreholes larger than those made by potato tuber moths.

Favorable conditions:

• Persistent dry weather with lesser or no rainfall, reduced humidity & 16 - 23 ^OC temperature favor the development of cutworm

Natural enemies of cutworm:

• Parasitoids: Trichogramma spp., Tetrastichus spp., Telenomus spp., Bracon spp., Campoletis spp., Chelonus spp., Ichneumon spp., Carcelia spp. etc.
• Predators: Lacewing, ladybird beetle, spider, red ant, dragonfly, robber fly, reduviid bug, praying mantis, King crow etc.

Tobacco caterpillar

Biology:

It is found throughout the tropical and sub-tropical parts of the world, wide spread in India. Besides tobacco, it feeds on cotton, castor, groundnut, tomato, cabbage and various other cruciferous crops.

• Egg: Female lays about 300 eggs in clusters. The eggs are covered over by brown hairs and they hatch in about 3-5 days.
• Larva: Caterpillar measures 35-40 mm in length, when full grown. It is velvety, black with yellowish – green dorsal stripes and lateral white bands with incomplete ring – like dark band on anterior and posterior end of the body. It passes through 6 instars. Larval stage lasts 15-30 days
• Pupa: Pupation takes place inside the soil. Pupal stage lasts 7-15 days.
• Adult: Moth is medium sized and stout bodied with forewings pale grey to dark brown in colour having wavy white crisscross markings. Hind wings are whitish with brown patches along the margin of wing. Pest breeds throughout the year. Moths are active at night. Adults live for 7-10 days. Total life cycle takes 32-60 days. There are eight generations in a year.

Damage symptoms:

• In early stages, the caterpillars are gregarious and scrape the chlorophyll content of leaf lamina giving it a papery white appearance.
• Later they become voracious feeders making irregular holes on the leaves.
• Irregular holes on leaves initially and later skeletonization leaving only veins and petioles
• Heavy defoliation.

Favorable conditions:

• Maximum S. litura built up at temperature ranges from 26 to 35.1°C, relative humidity ranges from 89 and 62%, zero rainfall, total sunshine hours (64.6 hrs/week).
• S. litura population showes a positive correlation with relative humidity, sunshine hours, whereas negatively correlated with wind velocity.

Natural enemeis of tobacco caterpillar:

• Parasitoids: Trichogramma sp., Tetrastichus spp., Telenomus spp., Bracon spp., Campoletis spp., Chelonus spp., Ichneumon spp., Carcelia spp etc.
• Predators: Lacewing, ladybird beetle, spider, red ant, dragon fly, robber fly, reduviid bug, praying mantis, King crow etc.

Leaf eating caterpillar / gram pod borer

Biology:

• Egg: The spherical, yellowish eggs are laid singly on tender parts and buds of plants. The egg period lasts for 2-4 days.
• Larva: Caterpillars vary in colour, initially brown and later turn greenish with darker broken lines along the side of the body. The larval period lasts for 18-25 days. Body covered with radiating hairs. When full grown, they measure 3.7 to 5 cm in length. The full grown caterpillar pupates in the soil in an earthen cell and emerges in 16-21 days.
• Pupa: Pupation takes place inside the soil. Pupal stage lasts 7-15 days.
• Adult: Moth is stout, medium sized with brownish/grayish forewings with a dark cross band near outer margin and dark spots near costal margins, with a wing expense of 3.7cm.

Damage symptoms:

• Young larva feeds on the leaves.
• Feed on leaves, shoots and buds

Natural enemeis of leaf eating caterpillars / gram pod borer:

• Parasitoids: Trichogramma spp., Tetrastichus spp., Telenomus spp., Bracon spp., Campoletis spp. Chelonus spp., Ichneumon spp., Carcelia spp. etc.
• Predators: Lacewing, ladybird beetle, spider, red ant, dragonfly, robber fly, reduviid bug, praying mantis, King crow etc.

White grub / root grub

Biology:

White grubs are the larval form of beetles. The length of the life cycle varies from 1–4 years, depending on the species.

• Egg: This insect develops by laying eggs. Females lay 50–100 eggs individually or in groups in small cells composed of soil particles glued together with a sticky substance secreted by the beetle. Eggs hatch in 1 to several weeks, and grubs feed on roots of plants until cold weather when they move down 10– 12 inches below the soil surface to spend the winter.
• Larva: They are large reaching 2-3 cm in length, are shaped like the letter C, and have three pairs of legs on their thorax. Their heads are hard and ruddy-brown in color, and they have strong mandibles. White grubs develop for up to seven months.
• Pupa: After 7 months the larva have a rest period of 40 days after which they pupate and remain in that form for two months.
• Adult: Pupa over winter deep in the soil for five to 10 months and become active again as the ground warms up in the spring then they pupate and transform into adults.

Damage symptoms:

• The grubs initially feed on rootlets/roots and then on tubers.
• The first stage grubs feed on live roots while the second and third instar grubs make large, shallow and circular holes in the tuber
• Tubers damaged by white grubs have irregular holes. More than two holes are often found in one tuber. These holes are not so deep, as white grubs do not enter and live.

Root-knot nematode & cyst nematode

Cyst nematode:

• One life cycle of the golden cyst nematode is completed with each crop.
• Between crops, eggs survive within cysts in the soil. When a potato plant is growing, substances exuded by the roots stimulate the eggs to hatch.
• Each egg contains a second-stage juvenile which hatches, moves from the cyst into the soil and penetrates a host root just behind the root-tip.
• The juvenile establishes a permanent feeding site in the root and develops to become an adult. Adult stage, males leave the root and move through the soil to find females.
• Females remain in the root, expanding and eventually rupturing it, remaining attached by the head and neck only.
• After fertilization, the female produces 300 to 500 eggs which it retains within her body. The female dies with the root, but her skin hardens and turns brown while forming a protective cyst for the eggs.

Damage symptoms: Root-knot nematode:

• Swelling of roots – Nematodes damage and live in the roots of potato plants, causing them to swell. Swollen roots cannot function normally and affect growth of the plant above them. In hot conditions, plants damaged by nematodes will show wilting.
• Irregular tuber shape – Tubers change shape and lumps appear on their surfaces. Heavily infested plants are stunted and exhibit early maturity. Reduction in size and number of tubers reduces the yield and warty 'pimple-like' outgrowths formed on tubers result in qualitative reduction.

Cyst nematode:

• Small patches of poorly growing plants appear in the field. Such plants show temporary wilting, stunting and premature yellowing symptoms. The size and number of tuber is reduced. Small mustard seed size yellow or white female nematodes are seen sticking to the roots.

Survival and spread:

• Primary: Cysts and egg masses in infected plant debris and soil or collateral and other hosts like Solonaceous, Malvaceous and Leguminaceous plants act as sources of inoculum
• Secondary: Autonomous second stage juveniles that may also be water dispersed

IPM for Potato

To know the IPM practices for Potato, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3   

 

112 ratings

Potato: Insect, Mite and Nematode Pests Management

1. Aphid
2. Leaf miner
3. Whitefly
4. Spider mites
5. Thrips
6. Jassid / leaf hopper
7. Potato tuber moth
8. Potato cutworm
9. Tobacco caterpillar
10. Leaf eating caterpillar / gram pod borer
11. White grub / root grub
12. Root-knot nematode & cyst nematode
13. IPM for Potato

Aphid

Biology:

• Aphids reproduce in two ways: by laying eggs and giving birth to young ones. Which birth process is used depends on environmental conditions and the availability of food.
• When food is plentiful, aphids give birth to live young. Populations develop quickly as this pest has many young ones, a short lifespan and pre-adult insects can also give birth.
• Eggs hatch after three or four days. Young aphids, called nymphs, need five to eight days to become adults

Damage symptoms:

• Direct damage: Aphids damage plants by puncturing them and sucking their juices. They damage the young and soft parts of plants, such as new leaves and shoots. Signs of damage are leaves not opening properly and being smaller in size. Severe infestation can cause shoots to wilt and dry out.
• Indirect damage: Aphids have wings and can move from plant to plant spreading viral diseases, picked up from infected plants. Aphids secrete a sugary liquid that stimulates black sooty mold growth. It can cover the surface of leaves which affects the way they absorb sunlight.

Favorable conditions:

• A relative humidity of 66 + 2.8% and 11 – 14⁰C temperature are ideal for development of this aphid.
• Its population sharply decreases with increase in RH over 73 percent.

Natural enemies of aphid:

• Parasitoids: Lysiphlebus sp, Diaeretiella sp., Aphelinus sp., Aphidius colemani etc.
• Predators: Ladybird beetle, lacewing, spider, hover fly etc.

Leaf miner

Biology:

It was introduced into India through Chrysanthemum cuttings.

• Egg: Eggs are laid inside leaves, they are very small and clear in color. Larvae hatch after about 2 - 3 days.
• Larva: Larvae remain inside leaves. They are very small and have no legs so cannot move from one leaf to another. The larval stage lasts around 6-12 days. Full grown larvae measure 3 mm.
• Pupa: These are formed in the ground or inside leaves. On potato plants, pupae usually fall to the ground. The pupal stage lasts around 14-16 days. Pupation takes place inside a thin loose mesh of silken cocoon.
• Adult: These are extremely small at 2-4 mm in length, black in color with two yellow spots on their backs, measuring 1.5 mm in length. They are most active in the morning from 7:00 to 9:00 and in the afternoon from 16:00 to 18:00. Adult flies produce an average of 166 eggs per female. They are attracted to the color yellow. The female fly punctures upper surface of leaf to lay eggs singly. The egg hatches in 4 days. Total life cycle takes 3 weeks. Generally it does not cause economic damage.

Damage symptoms:

• The leaf miner flies damage plants during its larval and adult stages mainly on the lower third of plants.
• Larvae begin eating the insides of leaves immediately after hatching, and bore mines inside them.
• In instances of severe infestation, all that is left of leaves is their upper and lower skins.
• Affected leaves become dry and drop off the plant.
• Adult flies puncture holes in leaves in order to lay eggs and feed on plant juices.

Natural enemies of leaf miner:

• Parasitoids: Chrysocharis pentheus , Gronotoma micromorpha, Diglyphus isaea etc.
• Predators: Lacewing, ladybird beetle, spider, red ant etc.

Whitefly

Biology:

• Egg: The female whiteflies lay eggs singly on the underside of the leaves. Eggs are smooth, sub elliptical, stalked, and broader at basal end. Its colour is light yellow, when freshly laid, turn dark brown later on. The eggs hatch in 5-17 days. Stalked nymph: It is louse like, sluggish creature having pale-yellow body. The nymphal stage lasts 14 to 81 days.
• Pupa: Convex in shape and possesses deep yellow patches on the abdomen.
• Adult: In 2-8 days, the pupae change into white flies. Adult fly is small winged insect having light yellow body of 1.0-1.5 mm length dusted with a white waxy powder. Wings are pure white and have prominent long legs. The life cycle is completed in 14-122 days. Eleven generations of this pest are completed in a year.

Damage symptoms:

• Chlorotic spots
• Yellowing
• Downward curling and drying of leaves.
• Vector of potato leaf curl disease

Favorable conditions:

• The temperature of 28-36 ⁰C and 62-92% relative humidity and scanty rainfall during August to January are quite favorable for this pest.

Natural enemies of whitefly:

• Parasitoid: Encarsia formosa, Eretmocerus spp. etc.
• Predators: Ladybird beetle, lacewing, spider, hover fly, reduviid bug, robber fly etc.

Spider mites

Biology:

• Egg: Eggs are hyaline, globular laid in mass
• Nymph: Yellowish in colour
• Adult: Red coloured small size

Damage symptoms:

• Affected leaves become reddish brown and bronzy
• Under severe infestation larvae construct silken webbing on the leaves
• Leaves wither and dry
• Flower and fruit formation affected

Natural enemies of spider mite:

• Predators: Predatory mites, predatory thrips, Oligota spp., Orius spp., anthocorid bugs, hover flies, mired bug etc.

Thrips

Biology:

Thrips are very small, have elongated abdomens and are yellowish or blackish in color. Although the adults have wings, these insect pests do not usually fly. They are often found on potato plants throughout all growth stages, from sprout development to tuber maturation. Thrips reproduce by laying eggs. Nymphs emerge from the eggs. It takes between 7 and 12 days to develop from eggs into adult thrips.

Damage symptoms:

As with aphids, thrips also cause direct and indirect damage:

• Direct damage: Thrips damage the undersides of leaves by sucking their juices. They damage young and soft parts of plants such as new leaves and shoots. As a result, leaves curl downwards and change to a blackish silver color. Severe infestation causes young leaves to wilt and dry out.
• Indirect damage: Thrips can carry and spread viral diseases.

Natural enemies of thrips:

• Parasitoids: Ceranisus menes
• Predators: Predatory thrips, minute piratebug, lacewing etc.

Jassid / leaf hopper

Biology:

• Egg: Elongated yellow-white eggs are deposited in leaf vein. It becomes greyish yellow before hatching. The female jassids lay about 15 eggs on the underside of leaves embedding them into leaf veins. The eggs hatch in 4-11 days.
• Nymph: Nymphs are pale – green, wedge shaped and their wing pads extend up to the fifth abdominal segment. The nymphal stage is complete in 7-21 days.
• Adult: It is a wedge shaped and pale green insect of about 3.5 to 5mm length having a black spot on each transparent forewing. It turns reddish brown during winter. Winged adults live for 35-50 days. This pest completes seven generations in a year.

Damage symptoms:

• Both nymphs and adults of Jassids suck plant sap as a result of their severe attack, the leaves curl; turn pale, bronze and dry up.

Favorable conditions:

• Temperature 27 to 36⁰ C and relative humidity below 75% favors the multiplication of Jassid.

Natural enemies of leaf hopper:

• Parasitoids: Anagrus flaveolus, Stethynium triclavatum etc.
• Predators: Lacewing, red ant, mirid bug, big-eyed bug, ladybird beetle etc.

Potato tuber moth

Biology:

• Eggs: The eggs are oval and measure less than 1mm in diameter. The female moth lays eggs on the underside of leaves or on exposed tubers near the eye. Each female can lay 150-200 eggs. Incubation period is 3-7 days.
• Larva: Newly emerged larvae are gray, yellowish white with brown head. Larval period is 15-20 days.
• Pupa: Full grown caterpillars come out of the tubers/ foliage and pupate in silken cocoons either in dried leaves, soils, over the stored tubers or in cracks and crevices in the store. Pupal period lasts for 11-12 days.
• Adult: It is a small grayish brown moth. Total life cycle is completed in 20-30 days at optimum conditions of 22-28⁰C temperature and 60-70% relative humidity. There are 8-9 overlapping generations in a year.

Damage symptoms:

• Potato tuber moths affect both tubers and foliage.
• Larvae eat their way inside tubers either in the field or the storage area.
• Severe infestation generally occurs in storage causing irregular galleries and 'tunnels' deep inside the tube.
• Larvae feces can be seen near bore holes.
• On foliage, larvae attack the stems and leaves of potato plants.
• They enter leaves, eat the inside and leave only a dried up outer skin.
• Severe infestation occurs in same areas, but yield loss is generally limited.

Natural enemies of potato tuber moth:

• Parasitoids: Chelonus blackburni, Copidosoma koehleri, Trichogramma spp., Apanteles sp., Pristomerus vulnerator etc.
• Predators: Lacewing, red ant, ladybird beetle, spider, robber fly, dragonfly etc.

Potato cutworm

Biology:

Cutworms damage potato plants, and affect almost all types of plants including weeds. Cutworms reproduce by laying eggs. Their life cycle includes eggs, larvae, pupae and moths. It takes up to 36 days for them to develop from eggs to adult insects. The various stages display the following characteristics:

• Egg: Eggs are creamy white, dome-shaped laid on the surface of the soil, but are very difficult to see. Each female moths come out at dusk and lay eggs (200-350) in clusters of about 30 each, either on the under surface of the leaves of host plants or in the soil.
• Larva: Newly emerged young larva is yellow or blackish- green in colour, 1.5 mm long with a shiny, black head and a black shield on the prothorax. The full-grown larva is about 42-45 mm long and is dark or dark brown with a plump and greasy body and lives in the soil. They have striped markings running down the sides of their bodies. The larval stage varies from 30-34 days,
• Pupa: Pupae are brown to dark brown, about 1.5 to 2.0 cm in length and are usually found in or on piles of leaf mould. Pupation takes place underground in an earthen chamber is completed in 10 to 30 days
• Adult: It measures about 25 mm from the head to the tip of the abdomen and looks dark with some grayish patches on the back and dark streaks on the forewings. Adults live for 7-10 days. The moths usually emerge at night. The life cycle is completed in 48 to 77 days. This pest generally completes three generations in a year.

Damage symptoms:

• These pests damage plants and tubers during dark.
• They attack young plants by severing their stems, pulling all parts of the plant into the ground and devouring them.
• Plants with severed stems have difficulty growing again.
• This pest can cause serious damage; particularly when crops are at 25 – 35 days after planting. Signs of damage on tubers are boreholes larger than those made by potato tuber moths.

Favorable conditions:

• Persistent dry weather with lesser or no rainfall, reduced humidity & 16 - 23 ^OC temperature favor the development of cutworm

Natural enemies of cutworm:

• Parasitoids: Trichogramma spp., Tetrastichus spp., Telenomus spp., Bracon spp., Campoletis spp., Chelonus spp., Ichneumon spp., Carcelia spp. etc.
• Predators: Lacewing, ladybird beetle, spider, red ant, dragonfly, robber fly, reduviid bug, praying mantis, King crow etc.

Tobacco caterpillar

Biology:

It is found throughout the tropical and sub-tropical parts of the world, wide spread in India. Besides tobacco, it feeds on cotton, castor, groundnut, tomato, cabbage and various other cruciferous crops.

• Egg: Female lays about 300 eggs in clusters. The eggs are covered over by brown hairs and they hatch in about 3-5 days.
• Larva: Caterpillar measures 35-40 mm in length, when full grown. It is velvety, black with yellowish – green dorsal stripes and lateral white bands with incomplete ring – like dark band on anterior and posterior end of the body. It passes through 6 instars. Larval stage lasts 15-30 days
• Pupa: Pupation takes place inside the soil. Pupal stage lasts 7-15 days.
• Adult: Moth is medium sized and stout bodied with forewings pale grey to dark brown in colour having wavy white crisscross markings. Hind wings are whitish with brown patches along the margin of wing. Pest breeds throughout the year. Moths are active at night. Adults live for 7-10 days. Total life cycle takes 32-60 days. There are eight generations in a year.

Damage symptoms:

• In early stages, the caterpillars are gregarious and scrape the chlorophyll content of leaf lamina giving it a papery white appearance.
• Later they become voracious feeders making irregular holes on the leaves.
• Irregular holes on leaves initially and later skeletonization leaving only veins and petioles
• Heavy defoliation.

Favorable conditions:

• Maximum S. litura built up at temperature ranges from 26 to 35.1°C, relative humidity ranges from 89 and 62%, zero rainfall, total sunshine hours (64.6 hrs/week).
• S. litura population showes a positive correlation with relative humidity, sunshine hours, whereas negatively correlated with wind velocity.

Natural enemeis of tobacco caterpillar:

• Parasitoids: Trichogramma sp., Tetrastichus spp., Telenomus spp., Bracon spp., Campoletis spp., Chelonus spp., Ichneumon spp., Carcelia spp etc.
• Predators: Lacewing, ladybird beetle, spider, red ant, dragon fly, robber fly, reduviid bug, praying mantis, King crow etc.

Leaf eating caterpillar / gram pod borer

Biology:

• Egg: The spherical, yellowish eggs are laid singly on tender parts and buds of plants. The egg period lasts for 2-4 days.
• Larva: Caterpillars vary in colour, initially brown and later turn greenish with darker broken lines along the side of the body. The larval period lasts for 18-25 days. Body covered with radiating hairs. When full grown, they measure 3.7 to 5 cm in length. The full grown caterpillar pupates in the soil in an earthen cell and emerges in 16-21 days.
• Pupa: Pupation takes place inside the soil. Pupal stage lasts 7-15 days.
• Adult: Moth is stout, medium sized with brownish/grayish forewings with a dark cross band near outer margin and dark spots near costal margins, with a wing expense of 3.7cm.

Damage symptoms:

• Young larva feeds on the leaves.
• Feed on leaves, shoots and buds

Natural enemeis of leaf eating caterpillars / gram pod borer:

• Parasitoids: Trichogramma spp., Tetrastichus spp., Telenomus spp., Bracon spp., Campoletis spp. Chelonus spp., Ichneumon spp., Carcelia spp. etc.
• Predators: Lacewing, ladybird beetle, spider, red ant, dragonfly, robber fly, reduviid bug, praying mantis, King crow etc.

White grub / root grub

Biology:

White grubs are the larval form of beetles. The length of the life cycle varies from 1–4 years, depending on the species.

• Egg: This insect develops by laying eggs. Females lay 50–100 eggs individually or in groups in small cells composed of soil particles glued together with a sticky substance secreted by the beetle. Eggs hatch in 1 to several weeks, and grubs feed on roots of plants until cold weather when they move down 10– 12 inches below the soil surface to spend the winter.
• Larva: They are large reaching 2-3 cm in length, are shaped like the letter C, and have three pairs of legs on their thorax. Their heads are hard and ruddy-brown in color, and they have strong mandibles. White grubs develop for up to seven months.
• Pupa: After 7 months the larva have a rest period of 40 days after which they pupate and remain in that form for two months.
• Adult: Pupa over winter deep in the soil for five to 10 months and become active again as the ground warms up in the spring then they pupate and transform into adults.

Damage symptoms:

• The grubs initially feed on rootlets/roots and then on tubers.
• The first stage grubs feed on live roots while the second and third instar grubs make large, shallow and circular holes in the tuber
• Tubers damaged by white grubs have irregular holes. More than two holes are often found in one tuber. These holes are not so deep, as white grubs do not enter and live.

Root-knot nematode & cyst nematode

Cyst nematode:

• One life cycle of the golden cyst nematode is completed with each crop.
• Between crops, eggs survive within cysts in the soil. When a potato plant is growing, substances exuded by the roots stimulate the eggs to hatch.
• Each egg contains a second-stage juvenile which hatches, moves from the cyst into the soil and penetrates a host root just behind the root-tip.
• The juvenile establishes a permanent feeding site in the root and develops to become an adult. Adult stage, males leave the root and move through the soil to find females.
• Females remain in the root, expanding and eventually rupturing it, remaining attached by the head and neck only.
• After fertilization, the female produces 300 to 500 eggs which it retains within her body. The female dies with the root, but her skin hardens and turns brown while forming a protective cyst for the eggs.

Damage symptoms: Root-knot nematode:

• Swelling of roots – Nematodes damage and live in the roots of potato plants, causing them to swell. Swollen roots cannot function normally and affect growth of the plant above them. In hot conditions, plants damaged by nematodes will show wilting.
• Irregular tuber shape – Tubers change shape and lumps appear on their surfaces. Heavily infested plants are stunted and exhibit early maturity. Reduction in size and number of tubers reduces the yield and warty 'pimple-like' outgrowths formed on tubers result in qualitative reduction.

Cyst nematode:

• Small patches of poorly growing plants appear in the field. Such plants show temporary wilting, stunting and premature yellowing symptoms. The size and number of tuber is reduced. Small mustard seed size yellow or white female nematodes are seen sticking to the roots.

Survival and spread:

• Primary: Cysts and egg masses in infected plant debris and soil or collateral and other hosts like Solonaceous, Malvaceous and Leguminaceous plants act as sources of inoculum
• Secondary: Autonomous second stage juveniles that may also be water dispersed

IPM for Potato

To know the IPM practices for Potato, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3   

 

112 ratings

Nutritional Deficiencies/Disorders of Potato

1. Nitrogen
2. Phosphorus
3. Potassium
4. Sulfur
5. Magnesium
6. Manganese
7. Molybdenum
8. Zinc
9. Boron
10. Calcium
11. Copper
12. Iron
13. IPM for Potato

Nitrogen

The yellowing in nitrogen deficiency is uniform over the entire leaf including the veins. Recovery of deficient plants to applied nitrogen is immediate (days) and spectacular. Younger leaves turn darker green, older leaves remain yellow. Upward cupping of deficient when severs.

Correction measure: Foliar application of 2% urea thrice at fortnightly interval or soil application of Nitrogen based on soil test recommendation.

Phosphorus

The symptoms first develop on older leaves showing some necrotic spots and plants are dwarfed or stunted. Phosphorus deficient plants develop very slowly. Plants develop a distinct purpling of the stem, petiole and the under sides of the leaves. Plant remains stunted, darker than normal color. Lower leaf surface gray-green. Leaflets roll upward, severely if deficiency is severe.

Correction measure: Soil application of recommended dose of phosphorous should be applied at the time of sowing or planting.

Potassium

Since potassium is very mobile within the plant, symptoms only develop on young and full sized leaves in the case of extreme deficiency. Leaflets become rugose (crinkled). Some of the leaves show marginal necrosis (tip burn), and at a more advanced deficiency status show interveinal necrosis. As the deficiency progresses, most of the interveinal area becomes necrotic, the veins remain green and the leaves tend to curl and crinkle. Leaves take on a scorched appearance with black pigmentation and necrtic (dead tissue) edges. In contrast to nitrogen deficiency, chlorosis is irreversible in potassium deficiency, even if potassium is given to the plants.

Correction measure: Foliar application of K₂SO₄ @1%.

Sulfur

This leaves show a general overall chlorosis. The veins and petioles show a very distinct reddish color. The yellowing is much more uniform over the entire plant including young leaves. The reddish color often found on the underside of the leaves. With advanced sulfur deficiency the leaves tend to become more erect and often twisted and brittle. Leaflet yellowing is uniform and general.

Correction measure: Apply gypsum@ 100 Kg /acre in soil and use sulphur containing fertilizers e.g. SSP. Foliar spray of K₂SO₄ or CaSO₄ @1% twice at fortnightly interval.

Magnesium

The Mg-deficient leaves show advanced inter veinal chlorosis. Interveinal necrosis causes scorched look. In its advanced form, magnesium deficiency may superficially resemble potassium deficiency. The symptoms generally start with mottled chlorotic areas developing in the interveinal tissue. Symptoms appear first on young mature leaves.

Correction measure: Foliar application of 0.2% MgSO₄.

Manganese

The leaves show a light interveinal chlorosis developed under a limited supply of Mn. The early stages of the chlorosis induced by manganese deficiency are somewhat similar to iron deficiency. As the stress increases, the leaves develop dark necrotic areas along the veins. Leave cup upward. Browing spotting ocurs on leaflets, especially along larger veins and mid-ribs.

Correction measure: Spray 0.2 % manganese sulphate 2-3 times at weekly intervals.

Molybdenum

The leaves show some mottled spotting along with some inter veinal chlorosis. An early symptom for molybdenum deficiency is a general overall chlorosis, similar to the symptom for nitrogen deficiency but generally without the reddish coloration on the undersides of the leaves.

Correction measure: Foliar spray of NaMO₄ 0.05% twice at weekly interval.

Zinc

The leaves show interveinal necrosis. In the early stages of zinc deficiency the younger leaves become yellow and pitting develops in the interveinal upper surfaces of the mature leaves. As the deficiency progress these symptoms develop into an intense interveinal necrosis but the main veins remain green, as in the symptoms of recovering iron deficiency.

Correction measure: Foliar spray of ZnSO₄ @ 0.5%.

Boron

These boron-deficient leaves show a light general chlorosis. Boron deficiency results in necrosis of meristematic tissues in the growing region, leading to loss of apical dominance and the development of a rosette condition. These deficiency symptoms are similar to those caused by calcium deficiency. The leaves are unusually brittle and tend to break easily. Also, there is often a wilting of the younger leaves even under an adequate water supply, pointing to a disruption of water transport caused by boron deficiency.

Correction measure: Foliar spray of borax @ 0.2%.

Calcium

The calcium-deficient leaves show necrosis around the base of the leaves. The very low mobility of calcium is a major factor determining the expression of calcium deficiency symptoms in plants. Symptoms show soft dead necrotic tissue at rapidly growing areas, which is generally related to poor translocation of calcium to the tissue rather than a low external supply of calcium. This ultimately results in the margins of the leaves growing more slowly than the rest of the leaf, causing the leaf to cup downward. Plants under chronic calcium deficiency have a much greater tendency to wilt than non-stressed plants.

Correction measure: Foliar spray of 2% Calcium sulphate twice at weekly intervals.

Copper

The copper-deficient leaves are curled, and their petioles bend downward. Copper deficiency may be expressed as a light overall chlorosis along with the permanent loss of turgor in the young leaves. Recently matured leaves show netted, green veining with areas bleaching to a whitish gray. Some leaves develop sunken necrotic spots and have a tendency to bend downward.

Correction measure: Foliar spray of 0.5% CuSO₄ twice at fortnightly interval.

Iron

The iron-deficient leaves show strong chlorosis at the base of the leaves with some green netting. The most common symptom for iron deficiency starts out as an interveinal chlorosis of the youngest leaves, evolves into an overall chlorosis, and ends as a totally bleached leaf. Because iron has a low mobility, iron deficiency symptoms appear first on the youngest leaves. Iron deficiency is strongly associated with calcareous soils, anaerobic conditions, and it is often induced by an excess of heavy metals. Growing point and young leaves become yellow or in extreme cases, white. Usually not accompanied by necrosis. Veins and leaflet ends remain green.

Correction measure: Soil application of 10 Kg/ acre FeSO₄ orspray 0.5% ferrous sulphate solution 2-3 times at weekly intervals.

IPM for Potato

To know the IPM practices for Potato, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3.07   

 

98 ratings

Potato: Natural Enemies

1. Natural Enemies of Potato Insect Pests
1. Parasitoids
2. Predators
2. Resistant/tolerant varieties
3. IPM for Potato

Natural Enemies of Potato Insect Pests

Parasitoids

Predators

Resistant/tolerant varieties

Name of variety	Disease/pest
Kufrianand	Moderate resistant to late blight. Immune to wart disease. Tolerant to hopper burn.
Kufriarun, Kufrihimalina	Moderate resistant to late blight.
KufriBadshah	Resistant to PVX, early and late blight
Kufrianand	Immune to wart disease; Tolerant to Gemini virus
Kufrichamatkar	Immune to wart disease; Resistant to early blight and charcoal rot.
Kufrichipsona- 1	Resistant to late blight.
Kufrichipsona- 2, Kufrifrysona	Resistant to late blight; Immune to wart disease
Kufrichipsona- 3	Resistant to late blight.
Kufrichipsona- 4	Field resistant to late blight.
Kufrifrysona	Field resistant to late blight; Immune to wart disease.
Kufrigaurav	Moderate resistant to late blight; High tolerance to nutrient stress.
Kufrigarima	Moderate resistant to late blight.
Kufrigirdhari	Highly resistant to late blight.
Kufrigiriraj, Kufrihimsona, Kufrijawahar	Moderate resistant to late blight; Immune to wart disease.
Kufrijeevan	Moderately resistant to early and late blight
Kufrijyoti, Kufrikanchan, Kufrikashigaro	Moderately resistant to early and late blight; Immune to wart disease.
Kufrikhyati	Field resistant to early and late blight.
Kufrikuber	Resistance to PLRV.
Kufrikumar	Immune to wart disease; Moderate resistant to late blight and charcoal rot.
Kufrikundan	Moderate resistant to late blight and resistance charcoal rot.

IPM for Potato

To know the IPM practices for Potato, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3.07   

 

104 ratings

Potato: Crop Stage-wise IPM

1. Pre sowing*
2. Sowing*
3. Vegetative/ seed/tuber stage
4. Tuber initiation
5. Vegetative and tuber development stage
6. Harvesting

Management	Activity
Pre sowing*
	Common cultural practices: • Summer deep ploughing • Soil solarization during summer. • Field sanitation, rogueing. • Avoid water logged conditions in the field. • Follow crop rotation. • Apply manures and fertilizers as per soil test recommendations • Start to grow ecological engineering plants. • Sow/plant 4 rows of maize, sorghum, bajra (pearl millet) around the potato crop field as a guard/barrier crop.
Nutrient	• Apply FYM @ 8 t/acre or vermicompost @ 4-6 t/acre • Apply 2 Kg each of Azospirillum and Phosphobacterium with 10 Kg FYM /acre as soil application before planting
Weed	• Stale seed bed technique before sowing. • Destroy all the germinated weeds by shallow ploughing before sowing.
Soil borne pathogens, nematodes and resting stages of insect pests	Cultural control: • Give light irrigation and cover the beds with polythene sheet of 45 gauge (0.45 mm) thickness for three weeks before sowing. • Raise African marigold in the nursery 15 days prior to sowing against cyst nematode. • Use raised seed beds of more than 35cm height (for better water drainage). Biological control: • Apply neem cake@ 80 Kg/acre.
Sowing*
	Common cultural practices: • Use resistant/tolerant varieties. • Use healthy, certified and weed seed free tubers.
Nutrients	• Apply 48 Kg nitrogen (N), 16 Kg phosphorus (P2O5) and 48 Kg potassium (K2O)/acre. • Apply N and K in two splits; half as basal and half as top dressing at 30 days after sowing.
Plant growth regulator (PGR)	• Dipp cut pieces of tuber (seed) for 10 minutes in chlormequat chloride 50% SL @ 100 ppm solution.
Weeds	• Adopt recommended agronomic practices like field preparation, time of sowing, row and plant spacing, gap filling etc. to obtain the healthy plant stand to reduce the weed menace. • If weed flora of the field is known based on previous season experience the preemergence recommended herbicide oxyflourfen 23.5% EC @170-340 ml in 200-300 l water/ acre be applied within 3-4 days after sowing. • When 5-10 % tubers are germinated, application of paraquat dichloride 24 % SL @ 200 gram a.i./acre can be used to control broadleaf, sedges and grassy weeds.
Resting stage of the diseases, black heart/ scurf	Cultural control: • Tubers stored in oxygen deficient structures should not be used. Chemical control: • Treat tuber with M.E.M.C. 6% FS @ 0.415 g/ Kg tubers in 100 ml water for 3-5 minute or soaking potato seed tubers in streptocycline 40 to 100 ppm solution for half an hour prior to planting or with carbendazim 25%+ mancozeb 50% WS @ (1.5 + 3.0) to (1.75 + 3.5) for 10 Kg seed (tuber) or with carboxin 37.5% + thiram 37.5% DS@ (1.5 + 3.0) to (1.75 + 3.5) for 10 Kg seed (tuber).
Vegetative/ seed/tuber stage
	Common cultural practices: • Collect and destroy crop debris • Judicious use of fertilizers • Provide irrigation at critical stages of the crop • Avoid water logging • Avoid any stress to the crop as much as possible • Enhance biocontrol activity by avoiding chemical spray, when 1-2 natural enemies are observed. Common mechanical practices: • Collect and destroy disease infected and insect infested plant parts • Collect and destroy eggs and early stage larvae • Handpick the older larvae during early stages of crop • Use yellow and blue sticky traps @ 4-5 trap/acre • Use light trap @ 1/acre and operate between 6 pm and 10 pm • Install pheromone traps @ 4-5/acre for monitoring adult moths activity (replace the lures with fresh lures after every 2-3 weeks) • Erect bird perches @ 20/acre for encouraging predatory birds such as King crow, common mynah etc. • Set up bonfire during evening hours at 7-8 pm Common biological practices: • Conserve natural enemies through ecological engineering • Augmentative release of natural enemies
Bacterial wilt	Cultural control: • Use pathogen free tubers. • Disinfect the cutting knife using 1% sodium hypochlorite solution. • Apply lime (dolomite) in the soil as acidic or alkaline soil is not conducive to the bacterial wilt pathogen. Biological control: • Apply neem cake @ 80 Kg/acre Chemical control: • Two to three sprays of (streptomycin sulphate 9% + tetracylin hydrocloride 1%) SP @ 40 to 50 ppm solution at an interval of 20 days. First spray 30 days after planting.
Root-knot nematode	Cultural control: • Plant crop during the 2nd week of October in autumn and in early January to limit rootknot nematode infestation on tubers. • Grow one row of repellent plants like Tagetes patula and T. erecta (African marigold) in between 2 or 3 rows of potatoes. Biological control: • Apply NSKE 4% and neem cake @ 80 Kg/acre.
White grub / root grub	Follow common cultural, mechanical and biological practices Biological control: • Entomopathogenic nematodes (EPNs) can be sprayed at the rate of 1 billion nematodes per acre, in white grub / root grub infested fields OR • EPN infected cadavers of Galleria/Corcyra larvae containing live infective juveniles (IJs) are implanted in soil at plant bases at the rate of four cadavers per plant during May/June and/or September for white grub / root grub control.
Tuber initiation
Leaf spot complex	• Follow common cultural, mechanical and biological practices
Early blight	• Follow common cultural, mechanical and biological practices Chemical control: • Spray aureofungin 46.15% w/v. SP @ 0.005% in 300 l of water/acre or captan 50% WG @ 600 g in 200 l of water/acre (second spray after 5 days interval) or captan 50% WP @ 1 Kg in 300- 400 l of water/acre or captan 75% WP @ 666 g in 400 l of water/acre. (second spray after 8 days interval) or chlorothalonil 75% WP @ 350-500 g 240-320 l of water/acre (second spray after 14 days interval) or copper oxychloride 50% WP @ 1 Kg in 300-400 l of water/acre or mancozeb 35% SC @ 0.5% or 500 g/100 l water 500 l water or as required depending upon crop stage and equipment used or mancozeb 75% WP@ 600-800 g in 300 l of water/acre or hexaconazole 2% SC @ 1.2 l in 200 l of water/acre (second spray after 21 days interval) or kitazin 48% EC @ 0.20% or 200 ml in 200 l of water or propineb 70% WP @ 300 g in 100 l of water or 0.30% as required depending upon crop stage and plant protection equipment used (second spray after 15 days interval) or zineb 75% WP @ 600- 800 g in 300-400 l of water/acre or captan 70% + hexaconazole 5% WP @ 200- 400 g in 200 l of water/acre (second spray after 21 days interval).
Late blight	• Follow common cultural, mechanical and biological practices Cultural control: • Use short-duration varieties. • The model specifies that 7 days moving sum of RH > 85% for at least 90 hr coupled with a 7 day moving sum of temperature between 7.2 and 26.6°C for at least 115 hr would predict appearance of late blight within 10 days of satisfying the conditions. Chemical control: • Spray captan 50% WG @ 600 g in 200 l water (second spray after 5 days interval) or captan 50% WP @ 1 Kg in 300- 400 l water/acre or captan 75% WP @ 666 g in 400 l water/acre (second spray after 8 days interval) or chlorothalonil 75% WP @ 350-500 g in 240-320 l of water/acre (second spray after 14 days interval) or copper oxychloride 50% WP @ 1 Kg in 300-400 l of water/acre or copper sulphate 2.62 % SC @ 400 ml in 200 l of water/acre (second spray after 3 days interval) or cyazafamid 34.5% SC @ 80 ml in 200 l water/acre (second spray after 27 days interval) or dimethomorph 50% WP@ 400 g in 300 l water/acre (second spray after 16 days interval) or mancozeb 75% WG @ 400 in 200 l water/acre (second spray after 3-5 days interval) or mancozeb 75% WP@ 600-800 g in 300 l water/acre or hexaconazole 2% SC @ 1.2 l in 200 l water/acre (second spray after 21 days interval) or mandipropamid 23.4% SC @ 0.2 ml/ l in 200- 300 l of water/acre (second spray after 40 days interval) or propineb 70% WP @ 300 g in 100 l of water or 0.30% as required depending upon crop stage and plant protection equipment used (second spray after 15 days interval) or zineb 75% WP@ 600- 800 g in 300-400 l of water/acre or captan 70% + hexaconazole 5% WP @ 200- 400 g in 200 l of water/acre (second spray after 21 days interval) or cymoxanil 8% + mancozeb 64% WP @ 600- 800 g in 200-300 l of water/acre (second spray after 10 days interval) or famoxadone 16.6% + cymoxanil 22.1% SC @ 200 ml in 200-300 l of water/acre (second spray after 27 days interval) or fenamidone 10% + mancozeb 50% WDG @ 500- 600 g in 200 l of water/acre (second spray after 30 days interval) or metalaxyl M 4% + mancozeb 64% WP @ 025% 1 Kg/ acre in 200-400 l water (second spray after 24 days interval) or metalaxyl 8% + mancozeb 64% WP @ 025% 1 Kg/ acre in 400 l water (second spray not less than7 weeks) or metiram 55% + pyraclostrobin 5% WG @ 600-700 g in 200 l water/ acre (second spray after 15 days interval) or azoxystrobin 23% SC@200 ml in 200 l of water/acre or treat tuber with carbendazim 25% + mancozeb 50% WS @ (1.5 + 3.0) to (1.75 + 3.5) for 10 Kg seed (tuber).
Leaf curl diseases	• Follow common cultural, mechanical and biological practices Cultural control: • Use peppermint repellant plant for whitefly (vector). • Show attractant plant like French bean to attract predatory thrips.
Spider mites**	• Follow common cultural, mechanical and biological practices Cultural control: • Grow flowering plants for natural enemies attraction: carrot family, bishop’s weed (spider mite destroyer), sunflower family, French bean (predatory mites) etc.
Leaf miner**	• Follow common cultural, mechanical and biological practices
Tobacco caterpillar**	• Follow common cultural, mechanical and biological practices Cultural control: • Grow castor as ovipositional trap crop. Biological control: • Release egg parasitoid, Trichogramma pretiosum@ 20,000/acre/week four times. • Spray NSKE 5% against eggs and first instar larva. • Apply entomopathogenic nematodes (EPNs) @ 2,50,000 infective juveniles of Steinernema feltiae/sq mt area.
Aphid, thrips** and leaf hopper (aphid's transmit potato virus Y (PVY) and potato leaf roll virus (PLRV), whitefly	• Follow common cultural, mechanical and biological practices Cultural control: • Use healthy seed, hot and cold weather cultivation, green manuring, irrigation, fertilizer application. • Plant early bulking and/or maturing cultivars to help seed production programme in areas having short aphid-free periods so that the seed crop may escape the population pressure of aphid vectors. Biological control: • Spray NSKE 5%. Chemical control: • Apply carbofuran 3% CG @ 6.64 Kg/ acre or oxydemeton–methyl 25% EC @ 0.4 l in 200- 400 l of water/acre or thiamethoxam 25% WG @ 40 g in 200 l of water/acre or phorate 10% CG @ 4 Kg/ acre or soil drenching of thiamethoxam 25% WG @ 80 g in 200 l water/ acre for aphid control. • Spray carbofuran 3% CG @1.328 Kg/ acre for controlling leaf hopper • Spray dimethoate 30% EC @ 264 ml in 200- 400 l water/acre for controlling thrips.
Cutworms**	• Follow common cultural, mechanical and biological practices Cultural control: • Attracting cutworm larvae using rice bran – heaps of rice bran should be placed in several places in the late afternoon. They can be removed from the rice bran on the next day and destroyed. • Flood field prior to planting - where/whenever possible farmers can consider temporarily flooding fields, particularly on severely infested fields.
Potato wart	• Follow common cultural, mechanical and biological practices Cultural control: • Adopt intercropping potato with maize or rotational crops such as bean and radish (reduce population of viable resting spores in soil)
Potato scab	• Follow common cultural, mechanical and biological practices Cultural control: • Use healthy tubers and treat the seed tubers with boric acid (3% for 30 minutes) before or after cold storage. • Maintain optimum soil moisture from tuber initiation. • Practice crop rotation with wheat, peas, oats, barley, lupin, soybean, sorghum, bajra and green manures crops. Chemical control: • Spray thiram 75% WS @ 25 g/ l water (second spray after 7-10 days interval)
Vegetative and tuber development stage
Nutrients	• Apply 2nd half of N & K at 30 days after planting after hoeing / weeding.
Plant growth regulators	• Apply mepiquat chloride 5% AS @ 1.25-1.5 l (mix 200 -300 ml of products in 10 l of water) at 45 days after sowing to restrict the excessive vegetative growth of potato and increasits yield • Apply gibberellic acid 0.001% L @ 180 ml in 450-500 l of water twice at 45 days after sowing and 65 days after sowing or Apply triacontanol 0.05% EC @ 0.50 l in 500-600 l of water twice at 30 and 45 days after sowing to enhance the yield
Weeds	• Hand tool weeding/hoeing along with earthing twice at 30 and 60 days after planting. • Pre-emergence application of oxyflourfen 23.5% EC @170-340 ml in 200-300 l of water/acre • Post-emergence overall/ inter-row application (at 5-10% emergence) of paraquat dichloride 24% SL @ 800 ml in 200 l of water/acre or 2,4-D dimethyl amine salt 58% SL @1.376 l in 160 l of water/acre. • Use mulch on ridges to suppress weed growth such as paddy straw, maize or sorghum stalks or farm refuses. • In hilly regions, used local available materials such as pine needles or leaf litter as mulch for controlling weeds and reduce run off loss and conserving moisture.
Potato tuber moth	• Follow common cultural, mechanical and biological practices Cultural control: • Grow intercrops such as cowpea, onion, maize, coriander, urdbean in 1:2 ratio • Rotate the potato crop with a non host cereal, cucurbit, or cruciferous vegetable crop • Grow repellant plants such as ocimum/basil • Use healthy seed, hot and cold weather cultivation, green manuring, irrigation, fertilizer application, storage and adoption of seed plot technique • Plant seed tubers at a depth of 10 cm • The fields should be ridged after 6 to 7 weeks of planting so that the tubers are buried at least 25cm below the soil surface • Timely and adequate irrigations minimize soil cracking and thereby reduce the risk of tuber exposure to potato tuber moth attack or their egg laying • Always keep the tubers underneath the soil surface Biological control: • Inundative release of T. pretiosum @ 0.4 lakh/acre 4-5 times from flower initiation stage at weekly intervals
Bacterial diseases, black surf / canker	• Follow common cultural, mechanical and biological practices Cultural control: • Soak seed tubers in a solution of trisodium phosphate (90 g/l of water) one day before sowing. The tubers should be thoroughly rinsed and dried in shade.
Potato virus Y, S, X	• Same as in aphid/thrips control
Bacterial soft rot	• Follow common cultural, mechanical and biological practices Cultural control: • Physical damage must be avoided as it encourages post harvest rots.
Harvesting
Weeds	• Prior to harvesting/ after harvesting left over weeds should be removed before shedding of their seeds to reduce the spread of weeds.
Potato tuber moth	Cultural control: • After harvesting, potatoes should be kept in heaps in cool places for another 10-15 days for drying and further curing of skin. Heaps 3-4 meter long, wide at the base and about 1 meter wide at the top are the best. In hills the harvested potatoes are spread in well-ventilated rooms for drying. • Fresh market potatoes should be stored between 5 to 6 °C. Potatoes that are used for making chips should be stored between 7 and 10 °C. • Collection of left over tubers in the field after harvesting • Storage of healthy tubers in moth proof structures
Bacterial soft rot	Cultural control: • Physical damage must be avoided as it encourages post-harvest rots. • Before storage curing is effective and non-chemical control method can be done by exposing tubers for 5 days at 15 – 20 °C and 90 - 95% RH.
Black heart	Cultural control: • Maintain cold storage at 4 °C or slightly higher. • Maintain proper aeration in the storage.
Note: Pesticides dosages and spray fluid volume are based on high volume sprayer. *Apply Trichoderma viride/harzianum and Pseudomonas fluorescens for treatment of seed tubers and soil application (if commercial products are used, check for label claim. However, biopesticides produced by farmers for own consumption in their fields, registration is not required). ** Pests of regional significance

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage

 

3.1