Horsegram Diseases and their Management

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Horsegram Diseases Cercospora leaf spot Bacterial leaf spot Anthracnose Root rot Mosaic complex Powdery mildew IPM for H...

Horsegram Diseases

Cercospora leaf spot

Disease symptoms:

Moist weather and splashing rains are conducive to disease development. Most outbreaks of the disease can be traced back to heavy rainstorms that occur in the area.
Infected leaves show small, brown, water soaked, circular spots surrounded with yellowish halo.
On older plants, the leaflet infection is mostly on older leaves and may cause serious defoliation. The most striking symptoms are on the green fruit.
Small, water-soaked spotsfirst appear which later become raised and enlarge until they are one-eighth to one-fourth inch in diameter.
Centres of these lesions become irregular, light brown and slightly sunken with a rough, scabby surface.
Ripe fruits are not susceptible to the disease. Surface of the seed becomes contaminated with the bacteria, remaining on the seed surface for some time.
The organism survives in alternate hosts, on volunteer horsegram plants and on infected plant debris.

Survival and spread:

The fungus survives on diseased plant debris .Fungus spreads about 3 m through the soil in one season.

Favourable conditions

Moist weather and splashing rains.
High humidity or persistent dew

Bacterial leaf spot

Disease symptoms:

This is a common disease of horsegram occurring on the foliage at any stage of the growth.
The pathogen attacks the foliage causing characteristic leaf spots and blight. 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

The bacterium is seed-borne

Favourable conditions

Rain splashes play an important role in the development and spreadof the disease.
Warm, rainy and wet weather is congenial

Anthracnose

Disease symptoms:

Symptoms are circular, black, sunken spots with dark center and bright red orange margins on leaves and pods
In severe infections, the affected parts wither off.
Seedlings get blighted due to infection soon after seed germination.

Survival and spread

The pathogens survive on seed and plant debris
Disease spreads in the field through air-borne conidia

Favourable conditions

The disease is more severe in cool and wet seasons.

Root rot

Disease symptoms:

The pathogens cause seed decay, root rot, damping-off, seedling blight, stem canker and leaf blight in horsegram
The disease occurs commonly at pod development stage
The affected leaves turn yellow in colour and brown irregular lesions appear on leaves.
Roots and basal portion of the stem become black in colour and the bark peels off easily.
When the tap root of the affected plant is split open, reddening of internal tissues is visible.

Survival and spread

Species are saprotrophic, occurring in the soil which is the source of primary infection.
Secondary infection occurs by means of asexual spores.

Favourable conditions

Moist soil and humid conditions favour the development of disease.

Mosaic complex

Disease symptoms:

Initially mild scattered yellow spots appear on young leaves
The next trifoliate leaves emerging from the growing apexshow irregular yellow and green patches alternating with each other
Spots gradually increase in size and ultimately some leaves turn completely yellow
Infected leaves also show necrotic symptoms.
Diseased plants are stunted, mature late and produce very few flowers and pods
Pods of infected plants are reduced in size and turn yellow in colour.

Transmission and Favourable conditions

The disease is transmitted in semi persistent manner by aphids and whiteflies.
Aphids are more active in warm summer conditions and increased their population as well as spread the viruses .

Powdery mildew

Disease symptoms:

White powdery patches appear on leaves and other green parts which later become dull coloured
These patches gradually increase in size and become circular covering the lower surface Also. 30
When the infection is severe, both the surfaces of the leaves are completely covered by whitish powdery growth.
In severe infections, foliage becomes yellow causing premature defoliation.
The disease also creates forced maturity of the infected plants which results in heavy yield losses.

Survival and spread

The pathogen has a wide host range and survives in oidial form on various hosts in offseason
Secondary spread is through air-borne oidia produced in the season.

Favourable conditions

Dry and moist weather (90% RH) favours disease development

IPM for Horsegram

To know the IPM practices for Horsegram, click here.

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

3

22 ratings

Horsegram Insect Pests

Pod borer

Biology:

Eggs: Development of egg lasts 4-21 days depending on weather conditions. Average fecundity is about 100-300, maximum 600 eggs.
Larva: Coloration of larvae is variable, from dirty greenish-gray to reddish; body length 15- 22 mm and larval period is about 19-40 days depending upon weather conditions.
Pupa: Pupa is brilliant, brown, fine punctured, to 7-10 mm in length; cocoon is thick, white, and usually covered with soil particles. Pupal period is about 12-18 days. Number of generations per year reaches three, though the third generation can be facultative. Overwinters as larva.
Adults: Body length 8-11 mm, wingspan 19-27 mm. Wings longer than abdomen, folding as roof. Forewing is yellow- or greyish-brown with characteristic light stripe along fore edge, with orange spot on basal third, and with dark fringe. Hind wings are light gray, with dark venation and dark double line near fringe; the fringe is long and light in colour. Top of abdomen with a tuft of golden-yellow hairs. Life span of adult is 20 days.

Life cycle

Damage symptoms:

Dropping of flowers and young pods
As the larva develops within the pod, faeces accumulate causing soft, rotten patches on the pod.
Seeds are either partially or entirely eaten, and considerable frass and silk are present.
Older pods marked with a brown spot where a larvae has entered

Natural enemies of pod borer:

Parasitoids:

Egg parasitoids: Trichogrammatoidea armigera,
Larval Parasitoids: Bracon hebetor, Phanerotoma sp., Tetrastichus sp, Phanerotoma planifrons

Nematode

Biology:

Most species of plant parasitic nematodes have a relatively simple life cycle consisting of the egg, four larval stages and the adult male and female.
Development of the first stage larvae occurs within the egg where the first molt occurs. Second stage larvae hatch from eggs to find and infect plant roots or in some cases foliar tissues.
Under suitable environmental conditions, the eggs hatch and new larvae emerge to complete the life cycle within 4 to 8 weeks depending on temperature.
Nematode development is generally most rapid within an optimal soil temperature range of 70 to 80°F.

Life cycle:

Damage symptoms:

Infected plants in patches in the field
Formation of galls on host root system is the primary symptom
Roots branch profusely starting from the gall tissue causing a ‘beard root’ symptom
Infected roots become knobby and knotty
In severely infected plants the root system is reduced and the rootlets are almost completely absent. The roots are seriously hampered in their function of uptake and transport of water and nutrients
Plants wilt during the hot part of day, especially under dry conditions and are often stunted
Nematode infection predisposes plants to fungal and bacterial root pathogens

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 inoculums.
Secondary: Autonomous second stage juveniles that may also be water dispersed.

Favourable conditions: Loamy light soils

IPM for Horsegram

To know the IPM practices for Horsegram, click here.

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

2.94

17 ratings

Horsegram Pests

Pests of National Significance in Sunflower

Pests of National Significance in Sunflower

Insect Pests

Sharpshooter leafhoppers: Bothrogonia albidicans (Walker) (Hemiptera: Cicadellidae)
Little bean bug: Chauliops choprai Sweet and Schaeffer (Hemiptera: Malcidae)
Pod borer: Etiella zinckenella (Treitschke) (Lepidoptera: Pyralidae)
Weevils: Alcidodes fabricii (Fabricius) (Coleoptera: Curculionidae), Apion sp. (Coleoptera: Apionidae)
Aphids: Aphis craccivora Koch (Hemiptera: Aphididae)
Pulse beetles: Bruchus spp., Callosobruchus spp. (Coleoptera: Bruchidae)

Diseases

Root rot: Pelicularis filamentosa
Cercospora leaf spot: Cercospora dolichos Ell. & Evir
Bacterial leaf spot: Xanthomonas phaseoli var. sojansis
Anthracnose: Colletrotrichum lindemuthiannum (Sacc. Angn.) Bri. and Cov.
Powdery mildew: Erysiphe polygoni DC.
Yellow mosaic virus

Weeds

Major Broadleaf weeds

Pigweed: Amaranthus viridis Hook. F. Amaranthaceae
Tick weed: Cleome viscosa L Capparidaceae
Horse purslane: Trianthema portulacastrum L. Aizoaceae
False amaranth: Digera arvensis Forssk. Amaranthaceae

Grassy weeds

Rabbit/Crow foot grass: Dactyloctenium aegyptium (L.) Beauv. (Poaceae)
Crab grass: Digiteria sanguinalis (L.) Willd. (Poaceae)

Sedges

Purple nutsedge: Cyperus rotundus L. (Cypraceae)

Nematode

Root-knot nematode: Meloidogyne incognita

IPM for Horsegram

To know the IPM practices for Horsegram, click here.

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

2.9

21 ratings

Horsegram Crop Stage Wise IPM

Management	Activity
Pre-sowing
	Common cultural practices: Crop rotation with non host crops Timely sowing should be done Field sanitation, rogueing Destroy the alternate host plants Apply manures and fertilizers as per soil test recommendations
Nutrients	Apply manures and fertilizers on soil test basis.
Weeds	Destroy weeds manually or by deep summer ploughing.
Soil borne pathogens Nematodes, Resting stage of insects	Cultural control: Deep ploughing of fields during summer to manage juvenile population of nematodes and insect pests. Soil solarization: Cover the beds with polythene sheet of 75 gauge thickness for six weeks before sowing to reduce the soil borne pests.
Sowing/seedling
	Common cultural practices: Do summer ploughing Timely sowing should be done Solarize the field in summer to help reduce the inoculums. Use resistant varieties Select seed from disease free fields
Weeds	Always use certified and weed free seeds. Timely sowing should be done. Line sowing should be done to facilitate inter-culture operations. Plant population should be maintained to its optimum right from its beginning to minimize the crop weed competition. Adopt suitable crop rotation to minimize dodder and orobanche weeds
Vegetative stage
	Avoid excess application of nitrogen Adopt the ecological engineering strategy. Conserve natural enemies Remove and destroy weeds periodically Removal and destruction of infected/infested plants Common biological practices: Conserve natural enemies through ecological engineering Augmentative release of natural enemies
Nutrients	Correct micronutrient deficiency if any in standing crop. Foliar application of Thiourea @500ppm solution twice: 1st spray during vegetative growth and 2nd spray at flowering stage. It is effective under all conditions.
Weeds	Keep field boundary & bunds free from weeds. The crop field should be weed free initially for 4-5 weeks by following timely hoeing and weeding. Inter-culture operation/hoeing should be done twice at 20 and 35 days after sowing-using hand hoe to remove all weeds in between the row.
Leafhopper	Biological control: Spray neem seed kernel extract (NSKE) 5%. Spray neem oil @ 1%
Little bean bug	Biological control: Spray neem seed kernel extract (NSKE) 5%. Spray neem oil @ 1%
Anthracnose, Bacterial leaf blight,Cercospora leaf spot	Cultural control: Early planting i.e. immediately after onset of monsoon. Grow crop on bower system to avoid soil contact. Maintain proper drainage in the field.
Powdery mildew	Cultural control: Bower system (maintain gapping) of cropping reduces the disease incidence
Root rot	Cultural control: Plant in well-draining soils. Prepare seed beds to enhance rapid germination Proper irrigation is provided to prevent flooding and saturated soil conditions. Soil amendment with farm yard manure @ 5 tonnes/acre
Mosaic complex	See the common cultural practices
Flowering
Pod borer	Cultural control: Follow the intercropping systems like horsegram +maize, horsegram+ finger millet Biological control: Conserve and augment common predators and parasitoids
Reproductive (pod development)
Pod borer	Cultural control: Follow the intercropping systems like horsegram +maize, horsegram+ finger millet Biological control: Conserve and augment common predators and parasitoids
Nutrients	Incorporate crop residues in soil immediately after harvest.
Weeds	Remove left over weeds to prevent weed seed spread in field.