Biology and life table of spider mite, Tetranychus macfarlanei baker and pritchard (Acari: Tetranychidae) on cucumber

Abstract

The life history of Tetranychus macfarlanei Baker and Pritchard on cucumber leaflets was studied at 25.00 ± 2.00 0C, 80 ± 5 per cent R.H. Life table parameters of T. macfarlanei was conducted at four different constant temperatures, 20 0C, 25.3 0C (lab. temperature during June-December 2018), 28 0C and 32 0C on leaves of cucumber with 16h: 8h L:D conditions in a BOD incubator. The results indicated that the total duration from egg to adult emergence was less in male (9.67 ± 0.69 days) as compared to female (11.65±0.77 days). The adults of T. macfarlanei reproduced sexually and parthenogenetically. During the total oviposition period, mated female laid 50.23±6.32 eggs while unmated female laid 21.13±4.89 eggs. The total life cycle from egg stage till death of mite showed that the males completed life cycle earlier within 24.90±1.98 days while females required 31.40±0.98 days. There was higher survival rate for T. macfarlanei at lower temperature (20 ⁰C), as well as at moderate temperature (25.3 ⁰C) compared with highest temperature of 32 ⁰C and 28 ⁰C. An average fecundity of mated females was highest (53.20 eggs) at 28 ⁰C. The innate capacity of increase (rm) and finite rate of increase (λ) of T. macfarlanei reached maximal values (0.123 and 1.131) at 32⁰C. The mean generation time (T) and doubling time (DT) were shortest (12.31 and 2.43) at 32 ⁰C followed by 28 ⁰C (14.78 and 2.75) and longest (20.07 and 6.60) at 20 ⁰C. The net and gross reproductive rates were maximum at 28 ⁰C (40.97 and 55.22). The overall results suggested that T. macfarlanei could develop and reproduce within a wide range of temperatures. The range 28-32 ⁰C was the most suitable for the development, survival rate and reproduction of the spider mite.