Host searching ability of genetically improved high temperature tolerant strain of Trichogramma chilonis ishii in sugarcane

Dispersal/host searching range of genetically improved (through selection) high temperature tolerant (htt) strain and local Ludhiana strain of Trichogramma chilonis was up to 10 and 8 m from the release point, respectively although parasitization of factitious host Corcyra cephalonica eggs was found to decrease with increase in distance from the parasitoid release point. The maximum parasitization was recorded at 1 m and least at 10 m from the release point. The parasitization efficiency of both the strains showed a negative and positive correlation with temperature and relative humidity, respectively. The searching range showed a slight decline in May as compared to April, which increased in June and July due to increase in temperature and then, showed an increasing trend in August, September and October with decrease in temperature. Searching range of htt strain had an edge over Ludhiana strain, irrespective of the change in temperature from April to October with mean parasitization in each month being significantly higher in former as compared to latter.