Aspects of the Biology and Morphometrics of the Life Stages of Epilachna chrysomelina Fabricius (Coleoptera: Coccinellidae)

Abstract

Aspects of the biology and morphometrics of Epilachna chrysomelina was investigated on cucumber at National Horticultural Research Institute, Ibadan under ambient conditions: temperature 25o ± 2o C and relative humidity 75 – 90%. The mean developmental period from egg to adult emergence was 29.00 ± 4.35 days. The beetle development was in four distinct stages; an egg, four larval instars, pupa and an adult stage. The mean eggs length and breadth were 1.33 ± 0.01 mm and 0.78 ± 0.01 mm. The first, second, third and fourth larvae measured (2.34 ± 0.50 mm and 1.26 ± 0.03 mm) (2.55 ± 0.90 mm and 1.48 ± 0.04 mm), (6.97 ± 0.70 mm and 2.97 ± 0.03 mm) and (8.15 ± 0.40 mm and 3.77 ± 0.07 mm) in length and breadth respectively. Mean pupal length and breadth were 6.33 ± 1.10 mm and 4.25 ± 0.25 mm with mean pupation period 5.20 ± 2.40days. The females were larger than the males. Pre-oviposition period was 7.20 ± 1.20 days with oviposition of 24.5 ± 4.5 days during which the female laid 222.20 ± 6.1 eggs. Epilachna chrysomelina is a key pest of cucumber resulting into huge loss in yield. The study provides useful information in identification of different biotypes of the beetle and its management.