Pea stem fly, Pea aphid and Pea leaf roller

Pea stem fly, Pea aphid and Pea leaf roller

4. Pea stem fly or bean fly, Ophiomyia phaseolii (Agromyzidae: Diptera)
  • Distribution: Sri Lanka, India, China, Indonesia, Malaysia, Philippines, Singapore and many African countries.
  • Host range: Cowpea, peas, lima bean, soybean and many other beans.
Damage:
  • The maggots mine through the leaf petioles into stems
  • Females also puncture the leaves.
  • Leaves turn yellow, giving the plants a dry appearance.
  • The stems turn brown, become swollen and break down.
  • Spring crop suffers less than the late summer crop
  • The attacked plants bear fewer pods which are mostly empty or having very small seeds.
Identification
  • Eggs are slender, oval, less than 0.5 mm long and white in colour.
  • Maggots are initially white, but latter turn yellowish.
  • They are small in size (less than 1mm)
  • Pupae are barrel shaped and brown in colour.
  • Adults are metallic black flies, 2.0 to 2.5 mm
  • Hyaline wings having a distinct notch in the coastal regions.
  • Female are slightly bigger than males, wing expense is on an average 5mm.
Life cycle
  • Total life cycle is completed in 2-3 weeks.
  • As many as seven generations.
  • The flies mate 2-6 days after emergence
  • Start oviposition 2-4 days after mating.
  • Incubation, larval and pupal periods last for 2-4, 9-12 and 18-19 days, respectively, during Nov-Dec.
  • Average longevity of male is 11 days; however, females can live up to 22 days.
Salient features
  • Eggs are laid singly in holes made on the upper surface of young leaves, especially near the petiole end.
  • On hatching, the maggot forms a short linear leaf mine
  • Further tunnels to the stem through leaf stalk
  • Pupation takes place inside the stem.
Management:
  • Remove and destroy all the affected branches during the initial stage of attack
  • In case of wide spread incidence, spray the crop with diamethoate @ 0.03% or oxy- demeton methyl @ 0.025%
  • Soil application of phorate 10G @ 10kg/ha is affective up to 40 days of sowing.
5. Pea aphid, Acyrthosiphum pisum (Aphididae: Hemptera)
  • Distribution: Cosmopolitan
  • Host range: Peas
Damage:
  • Nymphs and adults such the cell sap
  • Affected leaves get cupped or become irregularly distorted
  • Shoots become stunted and malformed
  • Also excrete honey dew which encourage sooty mould
  • Photosynthesis is affected
  • Plants become weak and the pod formation is adversely affected.
Identification
  • Adult aphids are large pear shaped, green, yellow or pink in colour with long conspicuous cornicles.
  • Both alates as well as apterous forms are present
Life cycle
  • Both alates as well as apterous forms are present
  • Only females and males are rare.
  • Males have been reported from Europe and USA but not from India.
  • Reproduction is parthenogenic and viviparous
  • About a week to complete one generation
  • Several overlapping generations in a year.
Management
  • This pest can be controlled by spraying the crop with dimethoate @ 0.03 per cent or oxy-demeton methyl @ 0.025 per cent.
  • Parasitoids also take care of this pest in nature
6. Pea leaf roller, Hedylepta (Nacoleia) indicata (Pyraustidae: Lepidoptera)
  • Hosts: Peas
Damage
  • Young caterpillars feed on green tissues of leaves
  • Later stages of caterpillars web the leaves together and feed within the folds
  • Skeletonizing the leaves completely.
Identification
  • Eggs are flat and scale like
  • Moths are fulvous yellow with abdomen showing white rings
  • Wings are suffused with fuscous except costa of fore wing and have discocellular spot
  • Fore wings have obliquely curved antemedial black line
  • Hind wings have post medial line bent outwards between vein 5 and 2.
  • Wing expanse is about 20 mm.
Life cycle
  • Incubation period is 4-6 days,
  • Larval period is13-15 days
  • Pupal period is 5-6 days,
  • Adult longevity is 5-6 days.
Salient features
  • Eggs are laid on the leaves in clusters of about 15 eggs each
  • On hatching the young caterpillars feed on green tissues of leaves
  • Latter they web leaves together and feed within the folds
Management
  • In nature, Cardiochila fulvus and Xanthopimpla punctata have been recorded parasitizing the caterpillars.
  • Need based spray of deltamethrin @ 0.0028%
Last modified: Saturday, 3 March 2012, 6:45 AM