THE INTRINSIC RATE OF INCREASE AND TEMPERATURE CO- EFFICIENTS OF THE COMSTOCK MEALYBUG, PSEUDOCOCCUS COMSTOCKI (KUWANA) (HEMIPTERA: COCCOIDEA: PSEUDOCOCCIDAE)

Abstract

THE INTRINSIC RATE OF INCREASE AND TEMPERATURE CO-EFFICIENTS OF THE COMSTOCK MEALYBUG,

PSEUDOCOCCUS COMSTOCKI (KUWANA) (HEMIPTERA: COCCOIDEA: PSEUDOCOCCIDAE).

Life history studies on the development of Pseudococcus comstocki (Kuwana) were made under laboratory conditions at four constant temperatures, namely 18, 22, 26 and 30°C. Temperature proved to have a significant effect on development, survival, reproduction and longevity, and on the sex ratio of P. comstocki. Reproduction, survival and longevity were greatest at 22-26°C and lowest at 30°C, which was detrimental to the nymphs. It was also found that the sex ratio became female biased at 30°C. On the basis of these data, the intrinsic rate of natural increase (rm) was computed to be 0.05, 0.07, 0.10 and 0.08 at the above temperatures and the gross reproduction rate (GRR) was also temperature dependent and was calculated to be 153, 249, 210 and 57. The lower temperature threshold for development (TL) was estimated to be 11.0°C and the time from birth to adulthood (K) 523 degree days.

Key words: potato sprouts, fecundity, weight gain, crowding, sex ratio, mortality.