Diadegma semiclausum Hellen

Diadegma semiclausum has restricted range of distribution. It has been recorded as a dominant parasitoid of Plutella xylostella in Kodaikanal and Nilgiri hills. It is also distributed in Himalayas, the upper range of temperature tolerance is 28°C. The parasitoid has an edge over all other parasitoids in its distribution range which also includes Cotesia plutellae.

The production procedure of Diadegma semiclausum is more or less similar to that of Cotesia plutellae. It however, does not do well when only mustard seedlings are used for multiplying Plutella xylostella. One hundred cocoons of D. semiclausum are kept in a petri plate. The parasitoids emerge in 7-10 days. After 24 hrs of adult emergence 200 2nd instar larvae reared on leaves of cabbage are exposed to the parasitoid females for a period of 24 hrs and then the exposed (parasitized) larvae on cabbage plant are kept back in separate cage for further development of the parasitoid. The parasitoid forms its cocoon inside the pupae of P. xylostella in 10 days time. The parasitoid completes its life cycle in 18 to 20 days. The females live for 14-20 days and produce about 170 eggs. The hosts are exposed to the females for two weeks.