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Insect Pests of Pigeonpea

 


Nodule damaging fly

Description

  1. Flies have black bands on their wings (Fig.).
  2. Eggs are laid on plants and in the soil.
  3. Larva is cream-colored and 10 mm long. 4.Pupation occurs in the soil. 5.One generation is completed in 4 weeks.

Damage symptoms

  1. The larvae penetrate the nodules making them hollow (Fig.).
  2. Feed upon the active nitrogen-fixing portions.
  3. Destruction of more than 90% of the nodules.
  4. Plants may show yellowing, indicating nitrogen deficiency and reduced growth.

Management

  1. No managent measures are recommended.
  2. Nitrogen fertilization to alleviate N deficiency due to nodule damage.

Adult fly

Maggot

   

Termite

Description

  1. Social insects that form colonies in chambers below the soil surface.
  2. Eggs are laid on plants and in the soil.
  3. Workers' are small (4 mm) and have a soft, white body and a brown head (Fig.).

Damage symptoms

  1. Wilting and death of plants with a hole in the stem, just below the soil surface.
  2. The stems are coated or 'sheeted' with soil (Fig.).
  3. Tunnels are seen in stem and roots when split. 

Management

  1. Seed treatment with aldrin or HCH. 2.Drenching of termite nests with aldrin or HCH solution.

Good cultivation practices to grow healthy plants.

 

   

Jewel Beetle

Description

  1. Apparently legless white larvae grow to a length of more than 20 mm. A characteristic bulb at the head and thorax region (Fig.).
  2. Pupates in the tunnel in the root or stem.
  3. The adult beetle is dark but iridescent, with a jewel-like shine. 

Damage Symptom

  1. Larva tunnels in the stem above and below the ground level.
  2. Prominent gall around the stem at ground level (Fig.).
  3. Wilting and death of young plants.
  4. Older plants may survive producing very few pods.

Management

  1. Seed treatment with Aldrin or HCH.

Good cultivation practices to grow healthy plants.

Gall around the stem

due to Jewel Beetle attack

  Jewel Beetle larva

   

Stem weevils

Description

  1. Adult beetle is 6 mm long and dark red or brown with white longitudinal stripes (Fig.).
  2. Eggs are laid on the stem.
  3. Larvae are white.

Damage Symptoms

  1. Young plants wilt (Fig.) due to girdling by adult beetle.
  2. Breakage of stem.
  3. Wilting and death of young plants.
  4. Older plants may survive producing very few pods.

Management

Seldom cause sufficient damage to merit any managent measures.

Adult beetle

Young plants wilt

 

Cowbugs

Description

  1. 7 mm long gray-brown bugs (Fig.) have thorn-like projections on the thorax.
  2. Eggs are laid on the stem.
  3. The nymphs exude a honey dew liquidwhich is used by ants.

Damage Symptoms

  1. The bugs suck the green stems.
  2. Formation of corky calluses.
  3. Wilting, and reduced plant vigor.

Management

Dimethoate used to managent major pests will reduce the cow bug population

Cowbug

Adults and Nymphs

attended by ants

   

Scale Insects

Description

  1. Young nymphs are mobile and spread by wind.
  2. Adult females are sedentary and are found in colonies.
  3. Ants are attracted to the honey dew and protect the colonies from the natural enemies. 

Damage Symptoms

  1. Drying of stems and leaves due to sucking of fluids (Fig.).

Management

  1. Seldom requires any management measure.
  2. Destruction of ant colonies will allow natural enemies to manage the spread of scale insects.

Colony of Scale Insects

and Drying of Stems and leaves.

   

Jassids

Description

  1. 2.5 mm long and small green insects (Fig.).
  2. Nymphs and adults are of same shape but nymphs do not have wings.
  3. Nymphs run sideways when disturbed.
  4. Eggs are laid along veins on the under side of the leaflets.
  5. One generation requires 2 weeks. 

Damage symptoms

  1. Leaflets are cup shaped (Fig.) with yellow edges and tips.
  2. Seedlings are stunted with red-brown leaflets (Fig.) followed by defoliation.

Management

Serious threat in the seedling stage. Any contact or systemic insecticide spray is adequate.

 

 

 

   

Aphids

Description

  1. Adults are black and shiny, up to 2 mm long
  2. Nymphs are smaller than the adults.
  3. Produce about 100 nymphs over a life-span of up to 30 days.

Damage symptoms

olonize the young shoots, flowers and pods(Fig.)..Leaves of young seedlings become twisted.

Wilting of seedlings.

Management

Seldom key economic pest..General predators such as lady-bird beetles and specific parasitoids like Ahytis spp inflict heavy mortality on aphid colonies. Rain and wind can dramatically reduce aphid infestations.

   

Mites

Description 

  1. The eriophyid mite (Fig.) can be seen with magnification.
  2. Light colored and spindle shaped eggs are deposited on young foliage.
  3. The red spider mite (Fig.) is larger, oval shaped, and dark red.
  4. Both mites complete a generation in less than 2 weeks. 

Damage symptoms

  1. Plants develop light green chlorotic foliage.
  2. Leaves will have mosaic pattern.
  3. Bronzing of leaves (Fig.) followed by defoliation with heavy infestation.
  4. Early infection results in sterile plants.

Management

  1. Not an economic pest by itself, but significant due to transmission of sterility mosaic disease.

Red Spider Mite

   

Weevils

Description

  1. Adults are 5 mm long with 11 black spots on its ash- grey body (Bottom Fig.).
  2. The biology is not fully known.

Damage symptoms

  1. Leaflets (Top Fig.) are chewed at the margins by adult beetles.

Management

  1. Not an economic pest and do not merit any managent measure.

   

Leaf Webbers

  1. Inconspicuous brown moth (Fig.).
  2. Eggs are laid in clusters of about ten, on buds and young leaves.
  3. Cream-yellow larvae pupates in the webs.
  4. The life-cycle takes 3-4 weeks.

Damage Symptoms

  1. Leaflets (Fig.), flowers and pods are held together to form a web.
  2. Larvae feed from inside these webs.
  3. Growth of the terminal shoot is impaired if infested.
  4. Infestations may begin as early as seedling stage and continue during flowering and podding.
  5. Late infestation may also result as pod borer.

Management

  1. Impact of damage is negligible. Use of chemical pesticides may have a negative impact on natural enemies.

Leaf Webber Symptoms

Leaf Webber Adult

   

Blister beetle

Description

  1. Adults (25 mm) (Fig. top) have very obvious black and red coloration.
  2. Eggs are usually laid in the soil.
  3. Larvae feed on the insects in the soil.

Damage symptoms

  1. Feed on the flowers and greatly reduce the number of pods that are set.

Management

  1. Manually picking them by hand (Fig. bottom) or collecting them with an insect net and crushing them without touching them with hand.
  2. Most insecticides are not very effective.
  3. Synthetic pyrethroids work reasonably well.

   

Pod Sucking Bug

Description

  1. The adults of Anoplocnemis spp are usually black or brown and are largest (30 mm) of these bugs (Fig.).
  2. Nezara viridula is normally green, but can be yellow or green and yellow.
  3. These bugs lay eggs in clumps on the leaf and pod surfaces.

Damage symptoms

  1. Sucks developing seeds through the pod wall.
  2. Seeds become shrivelled with dark patches (Fig.). Such seeds do not germinate and are not fit for human consumption.

Management

  1. Systemic insecticides such as Dimethoate and Monocrotophos are effective.

   

Pod Borer 

Description

  1. Adult moths have with dull brown forewings
  2. A single female can lay up to 2000 small eggs, usually singly. Eggs are laid on flower buds and young pods.
  3. Full-grown larvae are 30-40 mm long and may have various color and banding patterns.
  4. Pupation occurs in the soil or in plant debris.

Damage symptoms

  1. Destroys buds, flowers, and pods (Fig.).
  2. If flowers and pods are not available, larvae feed on foliage (Fig.).
  3. Single most constraint to pigeonpea production. 

Management

  1. Natural enemies: Manipulating natural enemy populations, including vertebrate predators such as birds.
  2. Application of high quality Helicoverpa Nuclear Polyhedrosis Virus (HNPV).
  3. Using plant-derivatives: Extracts of neem seed kernel, tephrosia, tobacco, pongamia, chili- garlic, and others.
  4. Plant protection operation should be initiated when one notices:
    1. small larva or 3 eggs per plant in short-duration cultivars.
    2. 3 small larvae or 5 eggs per plant in medium-duration cultivars.
  5. Slide 15

    small larvae or 10 eggs per plant in long-duration cultivars.

 

 

Legume Pod Borer

Description

  1. Adults have distinctive white bands on brown forewings.
  2. A full grown larva has a pale body lined by rows of conspicuous black spots on its dorsal surface.
  3. Eggs are laid in small clusters of 10 to 15 on leaves, buds, and flowers.

Damage Symptoms

  1. Larvae feed from inside a webbed mass of leaves,buds, and pods. Thus, Maruca is both a foliage feeder and pod borer.

Management

Chemical managent is difficult due to larvae live in well-protected webs. Systemic pesticides may accomplish more restraint than contact insecticides.

  

Larva with web  Egg on flower

    Adult Moth           Pupa

   

Plume Moth

Description

  1. Adults have brown plume-like wings (Top Fig.).
  2. Larvae are green or brown, spindle shaped and covered with short spines (Bottom Fig.).
  3. Green oval eggs are laid singly on buds and pods.
  4. The pupae which look like the larvae, are usually found attached to the pod surface or on the pedicel.

Damage symptoms

  1. Larvae chew into the buds, flowers, and pods.
  2. Small holes are seen in the buds and tender pods (Fig.).

Management

Several insecticides, including Endosulfan,can manage the plume moth. Its many natural enemies prevent it from building up into large populations.

          Plume moth Adult

Damaged Pod

   

Lima Bean Pod Borer

Description

  1. The moth has grey forewings with white coastal margin and the hind wings are pearly and translucent (Top Fig.).
  2. The young larvae are green but turn red later (Bottom Fig.).
  3. They feed inside the pod. White elliptical eggs are laid in small groups on the developing pods.

Damage symptoms

  1. Larvae infests maturing and dried pods.
  2. Faecal granules are found inside the damaged pods.

Management

  1. A minor pest and seldom merit specific manage.
  2. It is some concern in southeast Asia and can be managedled by systemic insecticides.

Adult Pod borer

Young Pod Borer Larvae

   

Pod Flies

Description 

  1. the adult is a small black fly (Fig.)
  2. The larvae are white legless and 3 mm long.They feed inside the green seed.
  3. The brown puparium is formed inside the pod but outside the seed.

Damage symptoms

  1. No external symptoms till the fully grown larvae chew holes in the pod walls and damage seeds.(Fig.)

Management

  1. Systemic insecticides such as dimethoate and monocrotophos are effective in managling the larvae feeding inside the seeds and pods.
  2. Non-systemic insecticides like endosulfan help in killing the adults.
 

   Eggs inserted         Adult Podfly
       in pods

Podfly Damage

   

Pod Wasp

Description

  1. The adult is a small wasp of 2 mm long.
  2. The legless white larva (2 mm long) feeds on the young green seed and inner pod wall (Fig.).
  3. Translucent, flat, oval eggs are laid on the flowers and on the young pods.

Damage symptoms

  1. Malformed and atrophied pods that do not develop (Fig.).
  2. Attacked locules remain undeveloped resulting in abnormal appearance of the pods.

Management

  1. Do not cause appreciable harm to warrant any management.
  2. Avoid growing a mixture of cultivars of different durations will help in reducing the build-up of the pest.
  3. Systemic insecticides such as Dimethoate and Monocrotophos will reduce population densities as it is an internal feeder.

Pod Wasp Larva, Pupa & Adult

Pod Wasp Damage

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