Scientific Name: Caryedon serratus (Olivier)
Common Names: Groundnut bruchid
Synonyms
Pachymerus serratus
Bruchus serratus
Taxonomic Position
Class: Insecta
Order: Coleoptera
Family: Bruchidae
Genus: Caryedon
Species: Caryedon serratus
Host Range
Groundnut, Tamarind, Acasia nilotica, palm kernels, cocoa beans and cotton seed cake.
Pest Destructive Stage
Primary pest
Eggs –laid or stuck individually onto seed or pod
Larvae – immobile, concealed within seed
Adults – do not feed on commodity, fly readily
Damage Symptoms
C. serratus infestation of groundnuts is revealed by larval emergence holes and the presence of cocoons outside the pods. Feeding damage to the seeds can be seen when infested pods are split open.
Identification Features
Egg
The eggs are translucent, white, oval and 1 mm long and 0.5 mm wide.
Larva
C. serratus larvae are scaribeiform and sparsely hairy. They usually leave the pods of their host before pupation.
Adult
- Body length 3.5-7.4 mm. Entire body is covered dorsally by golden scale-like setae.
- The adult beetle is reddish brown to reddish yellow in color with small black markings on the elytra.
- Antenna is serrate, 11 segmented and longer in male than female.
- Metathoracic femur is well developed with two rows of spines.
- The pygidium is exposed in case of female, while concealed in male.
- It has large prominent eyes and readily distinguished from the other storage pests by its broad hind femur, which bears a conspicuous comb of spines.
- Metafemora strongly thickened, with ventral, comb-like row of one large, sub median tooth followed by 8-12 small teeth.
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Dorsal View
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Head front view
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Hind leg - comb-like row of one large, sub median tooth followed by 8-12 small teeth
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Eggs, larvae and damage caused by peanut Bruchid
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Life Cycle
- The eggs are laid singly on the pods as well as on the seeds of its hosts or it may stick to the depressions on the shell of the nut or on the smooth testa of the kernels.
- The incubation period ranges from 6-15 days.
- The larvae are while but turn pink in later stages. The total larval period is 11-49 days depends on the temperature and host.
- The pupation takes place in the papery cocoons and period varies from 13 -23 days.
- The total development varies from 32-142 days. The pre –oviposition period is generally short and varies from 16-19 days.
Detection methods
Samples can be examined with naked eye or under magnifying glass or stereoscopic binocular microscope and by using soft X-ray and seed transparency method hidden infestation can be detected.