5. Legume pod borer or spotted pod borer, Maruca testulalis (Pyraustidae: Lepidoptera)
- Distribution: All tropical and subtropical regions of the world.
- Host range: Beans, peas, castor, ground nut, tobacco etc.
Damage:
- Caterpillars feed on reproductive parts of the flower
- Later they web the inflorescence with leaves, pods and then feed within
- Infested flowers do not develop into pods
- Affected pods become malformed
- Occasionally the older caterpillars also bore into peduncles and stems.
Identification
- Eggs are elongated oval in shape, less then 1mm in length, light yellow in colour
- Full grown caterpillars are 20mm long, light brown in colour with irregular brownish black dorsal, lateral and ventral spots
- Adults are medium sized slender moths.
- Hind wings are semi hyaline white with a brown distal patch.
- Wing expanse is 20-30 mm fore wings are brown with white spots.
Life cycle
- Eggs are laid singly on or near flower buds of the host plants
- Incubation period is 2-3 days
- Larval period is 8-4 days
- Prepupal period is 2 days
- Pupal period is 6-9 days
- Pupation takes place in debris or on soil surface.
6. Other pod borers
- Gram pod borer, Helicoverpa armigera (Noctuidae: Lepidoptera)
- Pea pod borer, Etiella zinckenella (Phycitidae: Lepidoptera)
- Pea pod borer, Sphenarches caffer (Pterophoridae: Lepidoptera)
- Blue butterfly, Eucharysops cnejus (Lycaenidae: Lepidoptera)
- Pea blue butterfly, Lampides boeticus (Lycaenidae: Lepidoptera)
Management of pod borers:
- Control measures recommended for H. armigera are effective against these borers also.
- Larval parasitoids Macrobracon hebetor, M. greeni, M. brevicornis are effective
7. Bihar hairy caterpillar, Spilarctia obliqua (Arctiidae: Lepidoptera)
- Distribution: Distributed in the orient. In India, it is serious in Bihar, MP, UP and Punjab.
- Host range: Polyphagous
Damage:
- Damage is caused by the caterpillars
- Eat away leaves and soft portions of stems and branches
- In severe, infestation the entire plant can be defoliated
Identification
- Eggs are light green and spherical
- Larvae are 40-45 mm when full grown and are covered profusely with grey hairs.
- Moths measure about 50 mm across the wings
- The head, thorax and under side of the body are dull yellow
- Antennae and eyes are black.
Life cycle
- The eggs hatch in 8-13 days
- Larval development is completed in 4-8 weeks
- Passing through seven stages
- Pupal stage last for 1-2 weeks
- Moths live for about a week
- Total life cycle is completed in 6-12 weeks
- 3-4 generations in a year.
Salient features
- The pest breeds during March-April and again from July to November
- Passes the hot summers and winter in pupal stage in plant debris.
- Adults emerge from the over wintering larvae in March
- Lay eggs in clusters on the underside of leaves
- Early instars are gregarious but later on they disperse
- Pupate in plant debris or in the soil
Management
- Collection and destruction of early gregarious caterpillars
- Pupae may be collected and destroyed at the time of summer ploughing
- Spray malathion @ 0.05% or dichlorvos @ 0.04%
8. Red hairy caterpillar, Amsacta moorei (Arctiidae: Lepidoptera)
- Distribution: Widely distributed in the orient including India.
- Host range: Polyphagous
Damage
- Caterpillars are damaging
- Young caterpillars prefer the growing points
- Older ones feed voraciously on all types of vegetation
- Moving army destroy field after field.
- Under sever infestations there can be complete failure of the kharif crops.
Identification
- Caterpillars are 25 mm, reddish amber with numerous long hairs
- Moths are stoutly built and have white wings with black spots
- The outer margins of the fore wings the anterior margin for the thorax and the entire abdomen is scarlet red
- There are black bands and dots on the abdomen.
Life cycle
- A single female can lay up to 1500 eggs
- Eggs hatch in 2-3 days
- Caterpillars grow through six stages
- Larval period is 15-23 days
- Pupate in soil
- Moths emerge next year.
Salient features
- This pest is active from mid June to the end of August
- Passes rest of the year in pupal stage in the soil
- Moths emerge usually with the first shower of the monsoons
- Eggs are laid in clusters on the under surface of the leaves
- The young caterpillars feed gregariously
- Pupate in soil
Management
- Use light traps.
- Collect and destroy young gregarious larvae
- Pupae may be collected and destroyed at the time of summer ploughing
- The pest can be controlled by spraying the crop with either of the following insecticides.
- Quinalphos @ 0.025% or malathion @ 0.05% or dichlorvos @ 0.04%
9. Other caterpillars
- Gram pod borer, H. armigera
- Tobacco caterpillar, Spodoptera litura and S. exigua
- Acherontia styx
- Pericallia ricini
MINOR PESTS OF BEANS
- Leaf miners:
- Cosmopleryx mimetis (Cosmopterigidae: Lepidoptera)
- C. Phaeogastra (Cosmopterigidae: Lepidoptera)
- Cyphostichia coerulea (Gracilaridae : Lepidoptera)
- Pod boring bugs:
- Riptortus fuscus (Coreidae: Hemiptera)
- R. linearis (Coreidae: Hemiptera)
- R. pedestri (Coreidae: Hemiptera)
- Thrips:
- Caliothrips indicus (Thripidae, Thysanoptera)
- Sericothrips ramaswomiahi (Thripidae, Thysanoptera)
- Frankliniella schultzei (Thripidae, Thysanoptera)
- Taeniothrips spp. (Thripidae, Thysanoptera)
- Stem boring beetle, Sagra nigrita (Chrysomelidae: Coleoptera)
- Leaf feeding beetle, Platypria histix (Hispidae: Coleoptera)
- Indian bean weevil, Colobodes dolichotis (Curculionidae: Coleoptera)
- Grey leaf weevil, Episomus lacerta (Curculionidae: Coleoptera)
- Stem gall weevil, Alcidodes spp. (Curculionidae: Coleoptera)
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