Biology of castor spiny caterpillar, Ergolis merione Cram. (Nymphalidae : Lepidoptera) on castor at five different temperatures

Abstract

Castor spiny caterpillar, Ergolis merione Cram. (Nymphalidae: Lepidoptera) has been reported as a major pest of castor. Outbreak of this insect occurs during September to December. The deleterious effect of the insect has attracted the attention of entomologists. To formulate the pest management strategies prior information like biology, host range nature and extent of damage, etc. are pre-reQuisite. Keeping in view the above facts, investigations were carried out on biology of this insect at five different temperatures, viz., 20°. 25°, 30°C and ambient temperatures in laboratory (i.e. 23±1.4°C) and field condition (i.e. 17±2.53°C) at Pantnagar during 1997-98. The experimental findings showed that the mean incubation period, larval period, and pupal period were significantly higher (4.74, 22.68. 11.5 days respectively) under field condition and significantly lower (3.08. 13.45, 4.06 days respectively) at 30°C. The mean adult longevity was highest at 30°C (male-4.34 days and female -4.9 days) as compared to other four conditions.