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)
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%
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