PESTS ON GROUNDNUT – free online study material

Insects

Aphid, Aphis craccivora     Hemiptera, Aphididae

  • They are small-sized insects (2 mm long), pear shaped, green, greenish brown or greenish black in colour.
  • Adults are mostly wingless but few winged forms also seen. It has 12-14 generations per year 
  • 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.

Leaf miner, Stomopteryx nertaria Lepidoptera: Gelechiidae

  • The larvae mine in to the leaves and 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.
  • Pupation takes place in the webbing. ETL is 2-3 larvae/plant or 10% leaflets damaged in central whorl. The adult is a brownish gray moth, 6 mm long with 10 mm wing span. Larvae green.


Stem borer, Sphenoptera perotetti  Coleoptera: Buprestidae

  • The adult is shiny beetle, 10 mm long and 3 mm wide.
  • The eggs are laid singly on the main stem. The grubs are slow movers having globular head and elongated, dorso-ventrally flattened body.
  • The grub burrows into the stem, close to the soil surface and kills the plant. 
  • Pupation takes place in the larval tunnel.
  • Infested fields show dead and dying plants, which when pulled up and examined grub/pupa can be seen in hollowed stem.

Termites Odontotermes obesus, Microtermes sp. Isoptera : Termitiidae

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



Bug – Elasmolemus sordidus Hemiptera: Lygaeidae

  • Active brown bug, Sucks oil from the kernels
  • The bugs hide within rubbish heaps of semi dried leaves. Attack the crop both in field and storage


Beetle– Caryedon serratus  Bruchidae, coleoptera



  • Major pests species of stored groundnuts. Adult females attach their eggs to the outside of pods or kernels. The first instar larva burrows directly through the pod wall to reach the kernel, where the larva feed and develop. 
  • A single larva can make a large excavation in the cotyledons, but no sign of damage is visible externally at this stage. Mature larvae emerge partially or completely from the pod and construct oval papery cocoon.
  • The adult is 4 to 7 mm long, with small black markings on the elytra. Very broad hind femur, serrate antennae and elytra do not completely cover the abdomen



Red hairy caterpillar Amsacta albistrica,     A.moorei, Arctiidae, Lepidoptera

  • Caterpillars cause defoliation. Voracious feeders and often migrate from one field to another devastating whatever crops come their way. The larva light brown and turns reddish as they grow. Haired and are up to 5 cm long.
  • 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. 
  • 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.



Bihar hairy caterpillar, Spilosoma obliqua Lepidoptera: Acrtiidae 

  • 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
  • The adult is a brown moth and a red abdomen. Eggs laid in clusters of 50-100, on the lower side of leaves. The larvae covered with long yellowish to black hairs.
  • 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.



Tobacco caterpillar Spodoptera litura Noctuidae, Lepidoptera

  • It is one of the serious pests of groundnut.
  • Freshly hatched larvae feed gregariously, scraping the chlorophyll. 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.
  • The adults are light brown moths. The egg masses 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.
  • Pupa reddish brown and is in the soil close to the plant.


Groundnut semilooper,  Plusia signata  Noctuidae, Lepidoptera

  • Larvae feed on the foliage
  • Larva green in colour 
  • Pupa in the soil

Gram pod borer, Helicoverpa armigera Noctuidae, Lepidoptera



Groundnut earwig, Euborelliastali Dermapetra: Anisolabiidae



Chafer beetle, Oxycetonia versicolor  Cetonidae: Coleoptera





Root grub, Holotrichia consanguinea   Melolonthidae: Coleoptera




Mite, Tetranchus urticae  Tetranychidae , Acarina

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