Integrated Pest Management

Early leaf spot

Causal Organism

Cercospora arachidicola

Damage

• Infection starts about 1 month after sowing.

• Small chlorotic spots appear on leaflets, with time they enlarge and turn brown to black and assume sub circular shape on upper leaf surface.

• On lower surface of leaves light brown colouration is seen.

• Lesions also appear on petioles, stems, stipules.

• In severe cases several lesions coalesce and result in premature senescence.

Survival & Favourable Conditions

• Monoculture of groundnut, lower temp (25^o C), long periods of high relative humidity and rainfall
  favour the disease.

Cultural Control

• Grow tolerant varieties can be grown wherever early leaf spot is severe.

• Intercropping pearl millet or sorghum with groundnut (1 : 3) is useful in reducing the intensity of early leaf spot.

• Crop rotation with non-host crops preferably cereals.

Mechanical Control

• Deep burying of crop residues in the soil, and removal of volunteer groundnut plants are important measures to reduce the primary source of infection

Biological Control

• Foliar application of aqueous neem leaf extract (2-5%) or 5% neem seed kernel extract at 2 weeks interval 3 times starting from 4 weeks after planting is good.
  

Chemical Control

• Spray carbendazim 0.1% or mancozeb 0.2% or chlorothalonil 0.2%.                                

Late leaf spot

Causal Organism

Phaeoisariopsis personatum

Damage

• Infection starts around 55-57 days after sowing in Kharif and 42-46 days after sowing in Rabi.

• Black & nearly circular spots appear on the lower surface of the leaflets.

• Lesions are rough in appearance. In extreme cases many lesions coalesce resulting in premature senescence and shedding of the leaflets.  

Survival & Favourable Conditions

• Temperature of 18-30^o C, leaf wetness and a total wetness and a late wet spell, magnesium deficiency and heavy application of nitrogen and phosphorus fertilizers favour the development of disease.

Cultural Control

• Use of resistant/tolerant varieties wherever late leafspot is severe.

• Intercropping pearl millet or sorghum with groundnut (1 : 3) is useful in reducing the intensity of late leafspot.

• Crop rotation with non-host crops preferably cereals.

Mechanical Control

• Deep burying of crop residues in the soil, removal of volunteer groundnut plants are important measures in reducing the primary source of infection.

Biological Control

• Foliar application of aqueous neem leaf extract (2-5%) or 5% neem seed kernel extract at 2 weeks' interval 3 times starting from 4 weeks after planting.

Chemical Control

• Spray carbendazim 0.1% or mancozeb 0.2% or chlorothalonil 0.2%.

Rust

Causal Organism

Puccinia arachidis

Damage

• Rust can be readily recognized as orange coloured pustules (uredinia) that appear on the lower leaflet surface and rupture to expose masses of reddish brown urediniospores.

• Pustules appear first on the lower surface and in highly susceptible cultivars the original pustules may be surrounded by colonies of secondary pustules.

• Pustules may also appear on the upper surface of the leaflet.

• The pustules are usually circular and range from 0.5 to 1.4 mm in diameter.

• They may be formed on all aerial plant parts apart from flower and pegs.

• Severely infected leaves turn necrotic and desiccate but are attached to the plant.

Survival & Favourable Conditions

• Wet weather coupled with a temp of 22-25^o C favours the disease.

Cultural Control

•  Crop rotation and field sanitation.

• Strict plant quarantine regulations should be enforced to avoid the spread of rust on pods or seeds to disease free areas.

• Early sowing in the first fortnight of June to avoid disease incidence.

• Intercropping pearl millet or sorghum with groundnut (1 :3) is useful in reducing the intensity of rust.

• Use resistant/tolerant varieties.

Mechanical Control

• Destroy volunteer (self sown) groundnut plants and crop debris to reduce / limit primary source of inoculum.

Biological Control

• Foliar application of aqueous neem leaf extract @ 2-5% is useful and economical for the control of rust.

Chemical Control

• Spray chlorothaalonil 0.2%; or
  mancozeb 0.25% or Hexaconazole/propaconazole to reduce disease incidence.

Aspergillus crown rot

Causal Organism

Aspergillus spp.

Damage

• Seeds may be killed in pre -emergence rotting.

• Post-emergence infection causes death and rapid decay of seedlings.

• Young plants collapse and die soon after emergence due to rotting of elongating hypocotyl.

• Collar region become dark brown & shredded.

• In mature plants large lesions develop on stem just below the soil surface & then spread upward along the branches causing wilting & death.

• The fungus sporulates on the surface of mature pods resulting in paths of black sooty spores.

Survival & Favourable Conditions

• Low soil moisture and high soil air temp between 30-35 C favour the disease development.

Cultural Control

• Crop rotation.

• Destruction of plant debris.

Mechanical Control

• Remove and destroy previous season's infested crop debris in the field

Biological Control

• Seed treatment with Trichoderma viride/T.harizanum @ 4 g/kg seed and soil application of Trichoderma viride/T.harizanum @25-62.5kg/ha, preferably in conjunction with organic amendments such as castor cake or neem cake or mustard cake @ 500 kg/ ha.

Chemical Control

• Seed treatment with 3 g thiram/ kg seed is recommended.

Stem rot

Causal Organism

Sclerotium rolfsii

Damage

• Development of white fungal threads over affected plant tissue particularly on stem.

• Base of the plant turns yellow and then  wilts down.

• Sheaths of white mycelium develop around the affected areas of the stem near the soil due to this the stem becomes shredded.

• White sclerotia of mustard seed size are produced in the infected tissues which later turn to brown colour.

• Seeds in the infected pods show a characteristic bluish-grey
  discolouration.

Survival & Favourable Conditions

• The disease is severe with alternate wet and dry periods.

Cultural Control

• Deep ploughing to bury surface litter, cultivation of groundnut in flat or lightly raised beds.

Biological Control

• Seed treatment with Trichoderma viride/T.harizanum @ 4 g/kg seed and soil application of Trichoderma viride/T.harizanum @25-62.5kg/ha, preferably in conjunction with organic amendments such as castor cake or neem cake or mustard cake @ 500 kg/ ha.

Chemical Control

• Seed treatment with 3 g thiram + Carbendazim is recommended.

Bud necrosis

Causal Organism

Peanut Bud Necrosis Virus (PBNV)

Damage

• Chlorotic spots appear on young leaflets and necrotic rings & streaks are developed.

• Terminal bud necrosis occurs when temperature is relatively high.

• As the plant matures it becomes stunted with short internodes and proliferation of auxiliary shoots.

• The virus is mainly transmitted by thrips.

Survival & Favourable Conditions

• The virus survives in the hosts of thrips and acts as a source of inoculums for the vector.

• The thrips are carried by wind.

• The population of vectors increases rapidly from January-March and August-September Kharif and hence the crop suffers a heavy loss in both the seasons.

Cultural Control

• Early sown crop during kharif and rabi/summer seasons is less infected.

• Grow resistant varieties.

• Destruct alternate weed hosts like Bidens pilosa, Erigon bonariensis, Tagetes minuta, Trifolium subterraneum.

• Increase plant density, do early sowing, mixed cropping with pearl millet to restrict vector movement.

• Groundnut should be intercropped with fast growing cereal crops such as pearl millet in 7:1 ratio.

Chemical Control

• Spray monocrotophos 1.6 ml/l or dimethoate 2 ml/l .

Kalahasti malady

Causal Organism

Tylenchorhynchus brevilineatus

Damage

• Infected plants appear in patches in the field, and are stunted with greener than normal foliage.

• Small, brownish lesions appear on the pegs, and on young developing pods.

• Peg length is reduced and in advanced stages of the disease the entire pod surface becomes blackened.

• Discolouration is also seen on roots.

Cultural Control

• Grow resistant varieties like Tirupathi-2 and 3 (TPT-3).

• The disease incidence is less in Groundnut fields sown after Rice

Chemical Control

• Apply carbofuran 4 kg a.i (133 kg)/ha 25-30 days after sowing along with irrigation water.

Alternaria leaf disease

Causal Organism

Alternaria arachidis and A. tenuissima

Damage

• Lesions produced by A. arachidis are brown in colour and irregular in shape surrounded by yellowish halos.

• Symptoms produced by A. tenuissima are characterized by blighting of apical portions of leaflets which turn light to dark brown colour.

• In the later stages of infection, blighted leaves curl inward and become brittle.

• Lesions produced by A. alternata are small, chlorotic, water soaked, that spread over the surface of the leaf.

• The lesions become necrotic and brown and are round to irregular in shape.

• Veins and veinlets adjacent to the lesions become necrotic. Lesions increase in area and their central portions become pale, rapidly dry out, and disintegrate.

• Affected leaves show chlorosis and in severe attacks become prematurely senescent.

• Lesions can coalesce, give the leaf a ragged and blighted appearance.

Chemical Control

• Foliar application of Mancozeb (0.3%) or copper oxychloride (0.3%) or Carbendazim(0.1%)

Anthracnose

Causal Organism

Colletotrichum dematium and C. capsici

Damage

• Small water-soaked yellowish spots appear on the lower leaves which later turn into circular brown lesions with yellow margin 1 to 3 mm in diameter.

• In some cases lesions enlarge rapidly become irregular and cover the entire leaflet, and extend to the stipules and stems.

Survival & Favourable Conditions

• The pathogen is seed, soil and air-borne.

Cultural Control

• Deep summer ploughing.

• Use healthy/certified seeds.

Mechanical Control

• Removal of plant debris.

Chemical Control

• Seed treatment with copper oxychloride or Mancozeb (0.3%) or Carbendazim (0.7%) are effective in controlling the anthracnose disease of groundnut.