Defoliators

Groundnut leaf miner (Stomopteryx subscecivella)

Identification & Monitoring

• The adult is a brownish gray moth, 6 mm long with 10 mm wing span.
• The eggs are shiny white and are laid singly underside of the leaflets.
• The larvae mine in to the leaves and are about 1 mm long at first and enlarge as the larvae grow.
• Pupation takes place in the webbing.
• Install pheromone trap @ 1/ha for monitoring
• It is severe during August-October.
• ETL is 2-3 larvae/plant or 10% leaflets damaged in central whorl

Damage

• Young larvae initially mine into the leaflets, feed on the mesophyll and form small brown
• blotches on the leaf.
• Later stages larvae web the leaflets together and feed on them, remaining within the folds.
• Severely attacked field looks "burnt" from a distance.

Cultural Control

• Stray planting of cowpea or soybean as trap crop.
• Crop rotation with non leguminous crop is advised in case of severe recurring problem.
• Crop rotation of groundnut with soybean and other leguminous crops should be avoided.
• Use resistant/tolerant varieties.

Mechanical Control

• Collect and destroy egg masses and early instars larvae.
• Install pheromone trap @ 5/ha for mass trapping.
• Spray neem based formulation @ 5%.

Biological Control

• Release Trichogramma Chilonis @ 50000/ha twice (7-10 days interval)
• Conserve the natural bio control population of spiders, long horned grasshoppers, praying mantis, robar fly, ants, green lace wing, damsel flies/dragon flies, flower bugs, shield bugs, lady bird beetles, ground beetle, predatory cricket, earwig, braconids, trichogrammatids, NPV, green muscular fungus.
• Mulching with rice straw causes reduction in leaf miner incidence and increase in percentage parasitism.
• Intercropping groundnut with Pennisetum glacum enhanced the parasitoid Goniozus spp. on leaf miner.

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Effective control could be achieved if insecticide is applied at 45 and 70 days after planting.
• Carbaryl 50WP 0.2 per cent spray was found to be most economical for controlling this pest; or Spray Quinalphos 25 EC 2ml or Methyldemeton 25 EC 1.6ml or Dimethoate 30 EC 2ml /lit of water.

Groundnut bud borer (Anarsia ephippias)

Identification & Monitoring

• The larvae are chocolate brown in color and 10-15 mm long.
• It prefers to bore into terminal buds and shoots

Damage

•  The larva bores into the terminal buds and shoots and tip of the stem.
•  The tender leaflets emerging from central spindle will show shot-hole symptoms initially.
•  In severe infestation emerging leaflets will have only the midribs or several oblong feeding holes.

Biological Control

• Neem oil 3 per cent and leaf extract of Vitex negumdo (nochi) 5 per cent were also effective against this pest.
• The hymenopteran parasitoids, Bracon gelechiiae Ashm and brachymeria sp cause parasitism up to 24 per cent on larvae

Chemical Control

• Spraying of monocrotophos 36SL 0.5 per cent (1.5 ml/lit) was found to be more effective in controlling the bud borer.                                                                                          

Bihar hairy caterpillar (Spilosoma (Diacrisia) obliqua)

Identification & Monitoring

• The adult is a brown moth with a 40-50 mm wing span and a red abdomen.
• Eggs are laid in clusters of 50-100, on the lower side of leaves.
• The larvae are covered with long yellowish to black hairs and are up to 5 cm long.
• Pupation takes place in the soil under dry foliage and debris.
• The pupa forms a thin silken cocoon by interwoven shed hairs of the larvae.

Damage

• Young larvae feed gregariously mostly on the under surface of the leaves.
• Feed on leaves and cause loss by way of defoliation.
• In severe cases only stems are left behind.
•  In defoliated crop it also feed on capsules.

Cultural Control

• Pre-monsoon deep ploughing (two/three times) will expose the hibernating pupae to sunlight and predatory birds.
• Removal and destruction of alternate wild hosts which harbour the hairy caterpillars.
• Grow trap crops like cowpea, castor and jatropha on field bunds to attract the caterpillars.
• Irrigate once to avoid prolonged mid season drought to prevent pre-harvest infestation.

Mechanical Control

• Setting up bonfires on field bunds during night.
• Mass collection and destruction of eggs and just emerged caterpillars.
• Place the twigs and leaves of calotropis, jatropha and papaya around the field to trap grown up caterpillars and destruction.

Biological Control

• Conserve the natural bio control population of spiders, long horned grasshoppers, praying mantid, robar fly, ants, green lace wing, damsel flies/dragon flies, flower bugs, shield bugs, lady bird
  beetles, ground beetle, predatory cricket, earwig, braconids, trichogrammatids, NPV, green muscular fungus.
• Use of NPV (nuclear polyhedrosis virus) on cloudy days at 500 LE/ha will be effective. Spraying of Bacillus thuringiensis is also advocated at 1 kg/ha where mulberry is not grown.
• Conserve the barconids parasites.

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Dust Lindan 1.3% or Fanvalerate 0.4% 15.20 kg/ha, the early stage is easy to control.
• Form a deep furrow trench around the field and dust with two per cent methyl parathion to prevent the mass migration of hairy caterpillars.
• Spraying of quinalphos 25 EC (2 ml/lit), or chlorpyriphos 20 EC (2.5 ml/lit) or endosulfan 35 EC (2.0 ml/lit) recommended when the caterpillars are younger.

Tobacco caterpillar (Spodoptera litura)

Identification & Monitoring

• The adults are light brown moths with a wing span of about 30 mm and mottled forewings.
• The egg masses about 4 X 7 mm appear golden brown on the upper surface of leaves.
• Young larvae are light green in color.
• Full grown larvae are stout, cylindrical and pale greenish brown with dark markings.
• The pupae are reddish brown and is in the soil close to the plant.
• The larvae feed mostly during night time.
• Monitor the flight intensity of the larvae using traps like pheromone trap.
• It is one of the serious pests of groundnut.

Damage

• Freshly hatched larvae feed gregariously, scraping the chlorophyll, soon disperse.
• Later stages feed voraciously on the foliage at night, hiding usually in the soil around the base of the plants during the day.
• Sometimes the feeding is so heavy that only petioles and branches are left behind.
• In light soil, caterpillar bores into the pods.

Cultural Control

• Deep summer ploughing.
• Early sowing to escape insect pest damage.
• Irrigate once to avoid prolonged mid season drought
• Planting castor or sunflower plants as trap crop for egg laying and destroying eggs or 1st stage larvae help in reducing the incidence.
• The sunflower act as bird perches as well.

Mechanical Control

• Install light trap.
• Two hand or mechanical weeding at 15-20 days after sowing.
• Use pheromone traps (5/ha) to monitor moth population.
• Install 10-12 bird perches per ha.
• Collection of egg masses/early instars larvae from trap crops.

Biological Control

• Conserve the natural bio control population of spiders, long horned grasshoppers, praying mantis, robar fly, ants, greenlace wing, damsel flies/dragon flies, flower bugs, shield bugs, lady bird beetles, ground beetle, predatory cricket, earwig, braconids, trichogrammatids, NPV, green muscular fungus.
• Release of Telenomus remus @ 50000/ha. 4 times (7-10 days interval) based on pheromone trap catching.
• Use SNPV @ 250 LE (6X 10^9/LE)/ha or B.t. @1 k.g/ha, when large number of egg masses and early instars larvae are noticed.
• Release Trichogramma chilonis @ 50000/ha. 2 times (7-10 days interval) based on on pheromone trap observation.
• Release of Bracon hebetor @ 5000/ha. two times at 7-10 days interval .
• Spray insect pathogenic fungus Nomuraea rileyi @10^13 spores/ha for controlling early instars.
• Release larval parasitoid apanteles africanus @ 5000/ha.
• Use 5% neem seed kernel extract on need basis.

Chemical Control

• Apply insecticides only if the insect population crosses the ETL.
• Apply Methyl parathion 2% dust @ 20 kg/ha or spraying of monochrotophos 36 SL or Quinolphos 25 EC @ 1500 ml or Endosulfan 35 EC @1250 ml or Trizophos 40EC @ 800 ml in
  700-800 lit of water.
• Poison bait with monocrotophos 36 SL or carbaryl, rice bran, jaggery and water can be used to control the grown up larvae.

Red Hairy caterpillars (Amsacta albistriga)

Identification & Monitoring

• The adults emerge from the soil at the onset of the south-west monsoon (usually in June).
• They are brownish-white moths with a 40-50 mm wing span.
• The larvae are light brown color and turns reddish as they grow and are haired and are up to 5 cm long.
• Erection of light traps soon after monsoon for monitoring pest.

Damage

• Caterpillars cause defoliation of the crop as they are voracious feeders and often migrate from one field to another devastating whatever crops come their way.
• After about 30-40 days of feeding the larvae burrow into soil, usually in the undisturbed soil of field or non-cropped areas and pupate.

Cultural Control

• Deep summer ploughing
• After the kharif crop, the field should be ploughed to expose the pupae to predatory birds.
• Early sowing is done to escape insect pest damage.
• Inter crop one row of castor for every 5 or 6 rows of groundnut.
• Crop rotation with sorghum/pearl millet or maize should be followed.
• Vegetative traps utilising Jatropa (wild castor) or Ipomoea prevent the migration of the grown up larvae.
• Irrigate once to avoid prolonged mid season drought to prevent pre-harvest infestation.

Mechanical Control

• Install of 12 light traps/ha or bonfire in endemic areas.
• Erection of light traps soon after the monsoon for 20-45 days and collecting and killing of adult moths are found very effective.
• Collection and destruction of egg masses in the fields around light trap areas.
• Install 10-12 bird perches/ha.
• Two hand or mechanical weeding at 15-20 days after sowing.

Biological Control

• Spray A-NPV (2X 10^5 PIB/I) and Bacillus thuringiensis (Bt).
• Release of Bracon hebetor @ 5000/ha. two times at 7-10 days interval.
• Conserve dominant predators like Coccinella sp. and Minochilus sexmaculata and parasitoids like Chelonus spp.
• Conserve the bio control population of spiders, long horned grasshoppers, praying mantis, robar fly, ants, green lace wing, damsel flies/dragon flies, flower bugs, shield bugs, lady bird beetles, ground beetle, predatory cricket, earwig, braconids, trichogrammatids, NPV, green muscular fungus.
• Use 5% neem seed kernel extract on need basis.
• Inter cropping with pigeon pea, mung bean and soybean provides increase in population of spiders.
• Population of coccinellids is higher on groundnut with maize, mung bean and soybean and Chrysoperla spp. is higher with maize and soybean intercrops.

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Dusting of Methyl parathion 2% @ 25 to 30 kg/ha or Fanvalerate 0.4% @15-20 Kg/ha.
• Spray Endosulfan 35 EC or Quinalphos 25 EC @ 1250 ml/ha or 500 ml of Nuvan (76%) 4 ml/ha to control full grown insect pests.

Gram pod borer (Helicoverpa armigera)

Identification & Monitoring

• The moths have a wing span of 40 mm and dull brown forewings.
• The creamy eggs are laid singly on young leaves and flower buds.
• The larvae are dark greenish brown and do not have black spots on thorax.
• Pupate in the soil
• Use sex pheromone trap for monitoring adult male population.

Damage

• Larvae feed on the foliage, prefers flowers and buds.
• When tender leaf buds are eaten symmetrical holes or cuttings can be seen upon unfolding of leaflets.

Cultural Control

• Deep summer ploughing
• Intercrop one row of red gram for every 5 or 6 rows

Mechanical Control

Install pheromone trap @ 5/ha

Biological Control

• Use Trichogramma chilonis @ 1 lakh/ha or Chrysoperla carnea @ 50000/ha at 40 and 50 days after sowing of groundnut can effectively check the pest.
• Apply H-NPV @ 250 LE/ha or B.t (Bacillus thuringiensis) 1 kg/ha or 5% NSKE for monitoring eggs and early instars larvae.
• Conserve the natural bio control population of spiders, long horned grasshoppers, praying mantis, robar fly, ants, green lace wing, damsel flies/dragon flies, flower bugs, shield bugs, lady bird beetles, ground beetle, predatory cricket, earwig, braconids, trichogrammatids, NPV, green muscular fungus

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Endosulfan in combination with gingelly oil or monocrotophos is found effective.
• Quinolphos 2ml or Chloropyriphos 3ml or Endosulfan 2ml /lit of water

Sucking pests

Aphids (Aphis craccivora)

Identification & Monitoring

• They are small-sized insects ( 2 mm long), pear shaped, green, greenish brown or greenish black in colour.
• The nymphs are dark brown and turns to shiny dark adults
• Adults are mostly wingless but few winged forms also seen.
• It has 12-14 generations per year. 50-100 aphids/plant

Damage

• Nymphs and adults suck sap from tender growing shoots, flowers, causing stunting and distortion of the foliage and stems.
• They excrete honeydew on which sooty molds flow forming a black coating.
• Aphids are also known to transmit peanut stripe virus and groundnut rosette virus complex.

Cultural Control

• Timely sowing of the crop.
• Varieties which are densely hairy and with stiff leaves interfere like Girnar 1

Mechanical Control

• Handpicking and destruction of various insect stages and the affected plant parts.

Biological Control

• Seed treatment with Trichoderma viride @ 4 gm/kg seed.
• Apply NSKE 5% (neem seed kernel extract) to control sucking pests.
• Augment the release of Cheilonenes sexmaculata @ 1250/ha.
• Conserve bio agents like flower bugs (anthocorids), lady bird beetles (coccinellids), praying mantis, hover flies (syrphids), green lace wing (chrysopids), long horned grass hoppers and spiders.

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Young crop may be applied with Monochrotophos 36SL 600ml/ha or Dimethate 30 EC @ 650ml/ha in 600 liter water.
• Dusting of Endosulphan 4% dust at 1 kg a.i./ha would be effective in controlling aphids.

Jassids  (Empoasca kerri Bachlucha spp)

Identification & Monitoring

• The eggs are inserted in to the leaf tissue close to the midrib or into the petiole.
• The egg hatch in a week and nymphs in to adult in 10 days.
• The infestation is high during August and September and February and March.

Damage

• Both nymphs and adults suck sap from central surface of leaves, inject toxins resulting in whitening of veins and chlorotic patches especially at the tips of leaflets, in a typical 'V' shape.
• Heavily attacked crop looks yellow and gives a scorched appearance known as 'hopper burn'.

Cultural Control

• Timely sowing of the crop and field sanitation.
• Grow tolerant varieties like Girnar 1
• Crop rotation with non host crop.
• Intercropping with pearl millet
• Avoid groundnut-castor inter crop, it increases the infestation.
• Irrigate once to avoid prolonged mid season drought to prevent pre-harvest.

Mechanical Control

• Collect and destroy the affected parts of the plant

Biological Control

• Conserve bio agents like praying mantis, long horned grass hoppers, dragon flies spiders, green muscardine fungus.

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Spray dimethoate 30EC @ 650ml/ha or Monochrotophos 36SL @ 600ml/ha in 600liter water.

Thrips  (Scirtothrips dorsalis, Thrips palmi)

Identification & Monitoring

• These are small insects live in the flowers and folded leaflets.
• These are about 10 mm long, pale cream in color and are hidden.
• The eggs are laid into young tissues of the plant.
• The nymphs become adult after 15 days through four instars.

Damage

• Nymphs and adults lacerate the surface of the leaflets and suck the oozing sap resulting in white patches on lower surface of the leaves and distortion of young leaflets.
• Severe infestations cause stunted plants.
• Thrips palmi transmits peanut bud necrosis.

Cultural Control

• Grow tolerant varieties like ALR 3, Robut 33-1, Kadiri 3 and ICGS 86031
• Several groundnut accessions like 21018 have been identified as resistant to thrips.

Mechanical Control

• Uproot and destroy severely infected plants.

Biological Control

• Conserve bio agents like flower bugs (anthocorids), lady bird beetles (coccinellids), praying mantis, green lace wing (chrysopids), long horned grass hoppers, dragon flies and spiders.

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Spray Monochrotophos 36SL 600 ml/ha or Dimethoate 30 EC 650ml/ha or Methyldemeton 25 EC 600 ml in 600 lit of water.
• Spray per acre monocrotophos 320ml mixed with neem oil 1lit and 1kg soap powder mixed in 200lit of water twice at 10days interval.

Root and Pod feeders

 Jewel beetle  (Sphenoptera indica)

Identification & Monitoring

• The adult is shiny beetle, 10 mm long and 3 mm wide.
• The eggs are laid singly on the main stem.
• The larvae are slow movers having globular head and elongated, dorso-ventrally flattened body.
• Population takes place in the larval tunnel.

Damage

• The grub burrows into the stem, close to the soil surface and kills the plant.
• Infested fields show dead and dying plants, which when pulled up and examined grub/pupa can be seen in hollowed stem.

Cultural Control

• Grow tolerant varieties.
• Deep ploughing in the summer.
• Use well decomposed organic manure.

Mechanical Control

• Manual destruction of infested plant stems may help in reducing its population.

Biological Control

• Conserve braconids, dragon flies, trichogrammatids, NPV, green muscardine fungus

Chemical Control

• Chemical insecticides should only be applied if the insect population crosses the economic threshold level (ETL).
• Applying carbofuran granules in the planting row can be effective prophyylactic measure.
• Apply 2.25 kg active ingradient per hectare of Carbofuran.

 Termites (Odontotermes spp)

Identification & Monitoring

• The termites favour red and sandy soils.
• These are social insects, live in termitaria, in distinct castes, workers, kings and queen.
• Eggs are laid on plants and in the soil.
• 'Workers' are small (4 mm) and have a soft, white body and a brown head

Damage

• Termites penetrate and hollow out the tap root and stem thus kill the plant.
• Bore holes into pods and damage the seed.
• It removes the soft corky tissue from between the veins of pods causing scarification, weaken the shells, and make them liable to entry and growth of Aspergillus flavurs thatproduces aflotoxins.

Cultural Control

• Digging the termitaria and destruction of the queen is most important in termite management.
• Use well rotten organic manure.
• Harvest the groundnuts as soon as they are matured, early removal of the produce from the field will reduce the chances of termite damage to pods.
• Clean cultivation
• Irrigate the crop frequently
• Thorough ploughing and frequent interculture

Mechanical Control

• Avoid physical loss of the crop during harvesting.
• Destruction of debris, termite nests and queen

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Apply chlorpyriphos 20 EC or Lindane 1.3% to control termites.
• Or apply dust of chlorpyriphos @ 30-40 kg/ha in soil before sowing.
• Seed dressing with insecticides such as 6.5ml of chloropyriphos /kg of seed may reduce termite damage.

 White grubs  (Holotrichia consanguinea, Holotrichia serrata)

Identification & Monitoring

• It is a polyphagus pest.
• Adults are 18-20 mm long and 7-9 mm wide.
• The eggs are white, almost round.
• The young grubs are translucent, white and 5 mm long.
• Beetles emerge out of the soil within 3-4 days after the onset of rain.
• Install light traps with the onset of rains and count the number of beetles per day.
• Dig 100 X 100 X 20 cm pit @ 10 pits per ha, collect and count the number of beetles per pt.

Damage

• Both adults and larvae are damaging stage
• The larvae feeds roots and damage pods.
• Grubs feed on fine rootlets, resulting in pale, wilted plants dying in patches.

Cultural Control

• Deep ploughing in summer.
• Always use well decomposed organic manure it attracts the adult beetles.
• Partial or complete lopping of host plants and retaining of a few most preferred host trees in the area for congregation of white grub adults.
• Crop rotation with sorghum/pearl millet or maize.
• Early sowing to avoid damage due to insect pest.
• Standing crops of fodder, sugarcane etc. are also protected.

Mechanical Control

• Collection and destruction of white grub adults from host trees around the field.

Biological Control

• Conserve braconids, dragon flies, trichogrammatids, NPV, green muscardine fungus.

 

Chemical Control

• Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL.
• Spray should be undertaken as a community approach and should be repeated after every rainfall till the middle of July.
• Spraying the trees close to the field with Chlorpyriphos 20 EC @ 2 ml/lit of water soon after first monsoon showers for 3-4 days in the late evening hours kills the adult beetles and reduces root grub infestation.
• Seed treatment with chlorpyriphos 20 EC ( 6.5 to 12.5 ml/kg seed) is found effective.
• In case of severe infestation apply 10% phorate @ 10 kg/ha.

Storage pests

 Groundnut bruchid  (Empoasca kerri Bachlucha spp)

Identification & Monitoring

• The adult is a brown beetle about 4-7 mm long and 5 mm wide , with large hind legs.
• The eggs are milky-white in color .

Damage

• The larva burrows through the pod wall and starts eating the seed.
• The damage can be diagnosed by the appearance of "windows" on the pod wall made by the grub before pupation, to facilitate adult emergence.

Cultural Control

• Dry the pods to optimum kernel moisture level of about 7 %.
• Store the pods in polythene-lined gunny bags and fill the top surface of the bag with a layer of 3 cm ht. sand.
• Mouth of bags should not be stitched or closed to avoid germination loss.
• Care should be taken to avoid breakage
• Broken seeds should not be stored for long periods.
• Dust an inert substance such as ABCD (attapulgite-based clay dust)

Chemical Control

• Chemical insecticides should only be applied if the insect population crosses the economic threshold level (ETL).
• Pods mixed with ABC (Attapulgite based clay) dust (5 g/kg pods) remain free from bruchid infestation for one year.
• Pods for seed purpose can be treated with thiram (3 g/kg pods) and kept free from infestation for one year.
• Celphos fumigation (3 g tablet per sack of groundnut (40 kg)) is also found effective in controlling the pest.

Disease Management in Groundnut

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.

Weed control

Normally, one or two hand hoeings and weedings should be done, depending upon soil type and extent of weed infestation. First hoeing should be done three weeks after sowing and the second, three weeks thereafter before commencement of flowering. Care should be taken that soil should not be distributed at pod formation stage. Weeds can also be controlled effectively by the application of Nitrogen (TOK-E-25) at the rate of 4 litres dissolved in 600 litres of water as pre-emergence spray. Fluchloralin (Basalin) at the rate of 1 kga.i. per hectare dissolved in 800-1000 litres of water can also be used as pre-planting spray.

The earthing up should be taken up simultaneously with intercultural operations. Basic idea of earthing up is to promote easy penetration of pegs in soil as also to provide more area to spread.

Disease management

Seed and Pre-emergence Rots

Rhizopus sp., Penicillium sp. and Aspergillus sp. are some of the common fungi which cause seed and pre-emergence rots. Due to these diseases patchy stand of the groundnut crop is usually seen. This is because of the poor seed germination and seedling rots. The seedlings which make their ways on the soil surface remain stunted and seldom develop to maturity.

Control Measures: Seed should be treated with Thiram at the rate of 3 g per kg seed.

Tikka

This disease is caused by the two species of the fungus, Cercospora; i.e., C. Personate and C. arachidicola. It spreads rapidly at a temperature above 22°C and when the relative humidity is higher. Small dark brown circular spots appear on the leaves. When the attack is severe, defoliation occurs and only the stem remains. The yield of susceptible varieties is substantially reduced.

Control Measures: (1) Treat the seed with Thiram at the rate of 5 g per kg of seed.
(2) Collect the affected plant debris and burn them.
(3) Give 4 sprays of Outer or Zineb or the rate of 2 kg in 1000 litres of water per hectare at an interval of seven to ten days. The first spray should be given as soon as initial symptoms are detected. Two sprays of Bavistin has been found very effective against this disease. Spray 0.05 percent solution of Bavistin.
(4) Grow some of the tolerant varieties like T-64, C-501, MH-4, TMV-6 and TMV-10.

Sclerotium Rot

This disease is caused by the soil-borne fungus, Sclerotium rolfsii. The affected plant parts show the development of the white thread-like fungal growth near the soil surface or just below the ground level. The affected plant parts later turn brown and small round bodies of about the size of a mustard seed are produced on the surface of affected tissue. The leaves turn yellow and then brown and later desiccate.

Control Measures: (1) Collect and burn the affected plant debris.
(2) Seed should be treated with Brassicol at the rate of 3 per cent.
(3) If the soils is infested heavily and their is no choice of crop to be followed in rotation, soil application of Brassicol at the rate of 10-15 kg per hectare is beneficial before sowing.

Rosette

This disease is caused by the virus transmitted through aphids. The plants affected by this disease look stunted and present bushy appearance. There is a marked reduction in the size of the leaflets and mottling becomes visible.

Control Measures: (1) Rogue out the infected plants as soon as they appear in the field.
(2) To check the spread of the disease, aphids should be killed by given a spray of Oxydemeton methyl (Metasystox) 25 EC at the rate of 1 litre dissolved in 1000 litres of water per hectare.

Charcoal Rot

This disease is caused by the soil-borne fungus, Macrophomina phaseoli, A red-brown water-soaked lesion appears on stem just above the soil level. The lesion spreads upwards on the stem and down into the roots and causes death of the plants. The dead tissue is covered with abundant sclerotia.

Control Measures: (1) Deep ploughing should be followed to bury the crop residues.
(2) Seed should be treated with Thiram at the rate of 5 g per kg of seed.
(3) Soil application of Brassicol at the rate of 10-15 kg per hectare before sowing should be done.

Rusf

This disease is caused by the fungus, Puccinta arachidis. The symptoms of the disease are characterised by the development of red pustules on leaves. Usually more pustules are found on the lower than on the upper surface. The pustules later on become dark brown. Under severe conditions defoliation and death of plants occur.

Control Measures: (1) Destroy by burning the diseased plant debris leftover after harvesting.
(2) Spray Zineb at the rate of 2 kg in 1000 litres of water per hectare. The first spray should be given as soon as the initial symptoms are observed. Three more sprays should be taken up at 10 days interval after the first spray.

Pest management

Groundnut is attacked Dy several insect pests. The major pests which attack the groundnut crop and their control measures are give below.

Groundnut Aphid

It is a polyphagous pest and both adults and nymphs prefer to feed on young shoots causing the leaves to curl due to desapping and subsequently the growth of the plant is stunted. Flowers and pods are also affected. They also transmit a virus disease known as rosette. Insects are mostly seen in colony on the underside of the leaves, top shoots and stems. Peak period of activity is during August. It prefers spreading and semi-spreading varieties as compared to bunch varieties.

Control Measures: Spray the crop either with Oxydemeton methyl (Metasystox) 25 EC at the rate of 1 millilitre per litre of water or Monocrotophos (Nuvacron) 36 SLat the rate of 1 millilitre per litre of water.

Groundnut Leaf Miner

The adults are small dark brown moth with a pale white dot on the front margin of the forewing. These moths lay minute eggs on tender shoots. The dark headed greenish to brown larvae mine into tender leaves which look like blister mine. In later stage of larva, it brings together the several leaflets, web them and feeds leisurely inside the fold. The attacked plants do not grow properly. This insect remains active from July to December.

Control Measures: Same as for aphids.

Termites

They feed on the roots of the groundnut crop with the result that ttw plants wither. The attack continues on pods. This weakens the shellsand make them liable to shatter or crack during harvest.

Control Measures: Mix 5 per cent Malathion dust at the rate of 25 kg per hectare in the soil at the time of last harrowings.

White Grub

With the first shower of rain in June, the beetles emerge from soil and live for a few days. These beetles feed voraciously on ber, guava, neem and other shrubs. They lay eggs in groundnut field. White grubs live in soil and remain active from July to September. The grubs feed on the functional roots of the plant, leaving behind only tap root. Grub infested plants turn pale, leaves and branches droop down and the plant withers and can be easily uprooted. It ultimately dies off resulting in patchy crop growth.

Control Measures: (1) Incidence of white grub population in the field may be checked by mixing Phorate (Thimet) 10% granules in the soil before sowing at the rate of 15 kg per hectare.
(2) Treat the seed before sowing with 12.5 ml chloropyriphos (Dursban20 EC) per Kg Kernels. Mix it properly and allow to dry. The seed can further be treated with fungicides like Thiram,

Thrips

The adults are as well as nymphs rasp the upper surface of the developing leaflets and suck the sap from them. As a result, the leaflets present a scarred or dried up appearance. In case of severe infestation, the plants look malformed and stunted. The leaflets loose their healthy green appearance and under surface of a leaves develop a brown coloration. The adults are dirty whitish in colour with fringed wings.

Control Measures: Same as for aphids.

Bihar Hairy Caterpillar

The caterpillars in their early stages feed gregariously on the lower surface of the leaves and the attacked leafs look like dirty paper. When grown up, they disperse all over the field and devour the leaves and top tender shoots. The badly affected crop is completely defoliated.

Control Measures: (1) Collect the egg masses and destroy them.
(2) Spray Endosulfan 35 EC or Quinalphos (Ekalux) 25 EC at the rate o' 1 millilitre per litre of water.

Green Stink Bug

Adults as well as nymphs suck the sap from softer tissues causing plants to become weak and pale. They also inject some toxic material while feeding, due to which the terminal shoots die.

Control Measures: Same as for aphids.