DEMECOLOGY OF THE FALSE SPIDER-MITE, BREVIPALPUS-PHOENICIS (GEIJSKES)(ACARI, TENUIPALPIDAE)

A life and fecundity table has been constructed for Brevipalpus phoeni cis, a serious pest of plantation crops, and various demographic param eters have been calculated. Although this mite has been found to posse ss a low growth rate (r(m) = 0.127), it possesses high rates of surviv al even in its senescence. Under constant experimental conditions the net reproduction rate is 33.2 eggs/mite, the generation time is 27.6 d ays and the population doubles once in 5.5 days. The stable age profil e of the population is distributed as 74.9%, 19.24% and 6.07% of eggs, immatures and adults, respectively. Another aspect considered in this paper is the evolution of the population in function of an effective initial population of 10 individuals. This mite takes a longer time to reach constant growth rate and stable age distribution (156 days), ho wever, the population growth is astronomical. The damage caused by the m passes beyond the economic injury level within 34 days by an effecti ve initial population of 10 mites in a tea bush having 100 leaves. Thi s suggests an earlier intervention to check the population. The demogr aphic analysis reveals that the following five aspects of its life his tory, namely high survival and fertility rates, reproductive intensity in the prime youth, lack of diapause, parthenogenetic mode of reprodu ction and euryphagy on perennial crops, are of major importance. Reaso ns for the importance of these characteristics are also discussed.