Studies on population ecology of thrips palmi 1. population growth and distribution pattern on cucumber in greenhouse
Kawai, A.
Japanese Journal of Applied Entomology and Zoology 27(4): 261-264
1983
ISSN/ISBN: 0021-4914 Document Number: 400173
Population growth and distribution pattern of T. palmi Karny on cucumbers in the greenhouse were investigated from Sept.-Nov. 1981. When 662 adults of T. palmi were released late in Sept., the tendency of increase in the number of adults per plant fitted well with the equation of exponential growth (Nt = N0 .cntdot. ert) until the leaves of cucumber plants were damaged by low temperature. The intrinsic rate of increase (r) was estimated to be 0.05/day. Adults of T. palmi were chiefly found on middle leaves (5-10 leaves beneath the apical leaf) before topping and apical leaves after topping. Larvae were chiefly observed in the lower leaves (10-15 leaves beneath the apical leaf) on which mostly adults had been observed 7 days before. Adults were distributed among plants at random. The distribution of larvae was moderately contagious. When leaf size was adopted as the size of the sampling unit, the distribution of both adults and larvae was highly contagious.