SchizotetranychusbaltazariRimando is a common pest of citrus in many parts of India and its feeding causes the appearance of yellowish white striplings on the leaves which later wither and defoliate. The occurrence of this pest on citrus plants grown in the orchard of Narendrapur campus was seen during the pre-monsoon and post-monsoon periods during 2008-2011. Since information on its life cycle is unavailable and as this pest is going to be a menace in citrus orchards, attempts were made to study life cycle of this pest mite at three varying temperatures, viz. 25, 27 and 29ºC on citrus under laboratory condition and the results thereof are presented in this paper.
This paper discusses the duration of different stages besides incubation, preoviposition, oviposition and post oviposition periods, fecundity, longevity, percentage of hatching, percentage of larva attaining adulthood etc. at three temperature regimes, 25, 27 and 29ºC. Incubation period was shorter at higher temperature and so also was the larval, protonymphal and deutonymphal periods. So far as egg-adult period is concerned, the duration was 13.70±0.21 days, 10.20±0.72 days and 7.30±0.76 days at 25, 27 and 29ºC, respectively. The preoviposition period was shorter (1.80±0.21 days) at 29ºC as compared to other two temperatures where it was 2.00±0.00 days and 2.00±0.45 days at 25 and 27ºC, respectively. The maximum oviposition period was 24.00±0.02 days at 29ºC and the minimum was 15.80±0.19 days at 25ºC. The postovipositionperiod(2.12±0.24days) was also higher at 29ºC as compared to other two temperatures. Fecundity both in case of mated and unmated females was much higher at 29ºC as compared to that at 25ºC but in case of 27ºC the difference was almost nil in case of mated female though in case of unmated female, the difference was quite noticeable. The longevity was more or less closer in males at all the temperatures but in case of female though there were differences but the values were quite close. So far as percentage of larva attaining adulthood and percentage of hatching, 29ºC proved to be better as compared to the other two temperatures. This indicated that 29ºC was more preferred by this mite as compared to 25ºC and 27ºC.

Keywords: Life cycle; Varying temperatures; Schizotetranychusbaltazari; Citrus; Sapota; West Bengal, India.