Biology and abundance of Cowpea weevil Callosobruchus maculatus

Biology and abundance of Cowpea weevil (Callosobruchus maculatus) on different leguminous seeds By: Garima Dr. Dakshina Seal University of Florida Department of Entomology and Nematology Institute of Food and Agricultural Sciences Tropical Research and Education Center

INTRODUCTION • Important pest of legume seeds • Origin: Africa • Coleoptetra: Bruchidae • Polymorphic: sedentary & Flightless • Cause ~90% of damage Female Calosobruchus maculatus feeding on Mung bean (Vigna radiata). • Used in rearing of Catolaccus hunteri Damage of Calosobruchus maculatus,

LIFE CYCLE • Eggs are oval or spindle shaped LARVAE EGGS • Larva is whitish • Sign of egg hatch: eggshell turns opaque LIFE CYCLE • Pupation stage: thinning of seed shell • Adult : Male – smaller plate and no strips Female- Larger plate, black on the side and white strip in the centre PUPA • Life cycle: 3 -4 weeks FEMALE

Materials and Methods Study 1: Fecundity • Five treatments including: • • Treatment (Scientific name) Common name Phaseolus vulgaris Black beans Vigna radiata Mung beans Vigna unguiculata Black-eyed peas Cicer arietinum Garbenzo, chickpea Phaseolus vulgaris Kidney beans Each treatment replicated three times. Black eyed peas is the control Each treatment has a pair of cowpea weevil. Eggs counted every alternate day until the male female died Black beans Mung beans Black-eyed peas Garbenzo Kidney beans

Study 2 : Sex Ratio Mung • Eggs are collected every alternate day from each petridish • Eggs laid on the same day put together in each treatment • Continue till female died in every replication of each treatment Eggs collected day 1 Eggs collected day 2 Eggs collected day 3 Mung Eggs collected day 4 Eggs collected day 5 Mung Eggs collected day 6

RESULTS Treatment Black-eye Garbenzo Kidney Mung Mean(eggs) 15. 28± 2. 85 a 12. 5± 2. 10 ab 5. 33± 1. 82 b 10. 16± 2. 47 ab 17. 39± 3. 68 a F=3. 22 df=4, 83 P=0. 0165

Treatment Black Male 0 c Female 0 c Black-eye 0. 87± 0. 17 a 1. 13± 0. 25 a Garbenzo 0. 42± 0. 12 b 0. 55± 0. 16 b Kidney 0 c 0 c Mung 1. 2± 0. 26 a F=17. 87 df=4, 410 P=0. 0001 1. 1± 0. 26 a F=17. 90 df=4, 410 P=0. 0001

Treatment Eggs Adults Black 259 0 Black-eye 226 160 Garbenzo 96 79 Kidney 177 0 Mung 313 200

Conclusion • Fecundity is more on mung followed by black beans • Male to female ratio is higher in mung than Black-eyed peas and Garbenzo • Emergence to fecundity percentage is highest in garbanzo followed by black-eyed pea and mung beans. • Mung beans are reliable for getting of Cowpea weevil adults for rearing of Catolaccus hunteri • Infested Garbenzo seeds with Cowpea weevil are effective for the infestation by Catolaccus hunteri

Future Research • The reason for non- completion of life cycle in Black beans and Kidney beans • Development of the resistant-varieties