Effect of host and temperature on reproducing of Diadegma semiclausum Hellen
Author of the article:CHEN Fu-Shou**, WANG Yan, ZHANG Hong-Mei ,YANG Yan-Xian , CHEN Zong-Qi***
Author's Workplace：Institute of Agricultural Environment and Resource, Yunnan Academy of Agricultural Science, Kunming 650205, China
Key Words：Diadegma semiclausu, parasitic rate, temperature, developmental duration, emergence rate, sex ratio
Abstract： [Obiectives] The effect of host and temperature on the reproduction of Diadegma semiclausum Hellen was studied, and the optimal larvae number, larval instars of Plutella xylostell (L.) and temperature for the reproduction of this species determined. [Methods] The effect of larvae number and instars of P. xylostella on the parasitization of D. semiclausu and the effect of temperature on the development time, emergence ratio and sex ratio of D. semiclausum were studied at six constant temperatures (15, 20, 22, 25, 27, 30℃) in the laboratory. [Results] Results show that the parasitization of D. semiclausum decreased with the increase of larvae numbers of P. xylostell from 30-90, but this decrease was not statistically significant. Parasitization significantly decreased when the number of larvae exceeded 90. D. semiclausum could parasitize the 2nd, 3rd and, 4th instars of DBM larvae, however, parasitization parasitization of the 2ndand 3rd instars was significantly higher than the 4th. Developmental time, emergence ratio and sex ratio of D. semiclausum were observed. Results show that the developmental time of an entire generation decreased significantly with increasing temperature from 15-27℃ and that pupae failed to develop when the temperature reached 30℃. The emergence ratio and sex ratio increased with increasing temperature from 15-22℃, and decreased with increasing temperature from 22-27℃.