Small scale field trials using the egg parasitoid <I>Trichogrammatoidea bactrae</I> (Nagaraja) to control the diamondback moth Plutella xylostella (L.) on Chinese kale

Small scale field trials using the egg parasitoid Trichogrammatoidea bactrae (Nagaraja) to control the diamondback moth Plutella xylostella (L.) on Chinese kalet

Jiraporn Petcharat, Assoc. Prof., D. of Pest Management, F. of Natural Resources, PSU.

Grant : The National Biological Control Research Center, NBCRC
Published : Thai J Agric Sci 1999, 32(3) : 385-390
Key words : Plutella xylostella, Trichogrammatoidea bactrae, biological control, diamondback moth, egg parasitoid

To evaluate the efficiency of the egg parasitoid Trichogrammatoidea bactrae (Nagaraji) (Hymenoptera : Trichogrammatidae) in controlling the diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera : Yponomeutidae), numbers of DBM larvae in no-parasitoid-released (untreated/control) and parasitoid-released plots (treated) were compared. The parasitoid-released plots were obtained by releasing egg parasitoids in a plot after the DBM-host plant (Chinese kale) was 30 day old. A piece of paper containing about 470 rice moth eggs which had been parasitized by T. bactrae was clipped under a kale leaf at a rate of 3 pieces/subplot/day for 7 day. Two days after the egg para-sitoids were released, 10 adult female DBMs/subplot were released in both 'no-parasitoid-released plots' and 'parasitoid-released plots' (200 female DBM/plot, in total). Four days after the adult female DBMs were released, kale leaves were randomly observed at a rate of 8 leaves/subplot for DBM larvae. It was found that there were 0.406ą0.295 DMB larvae/leaf in on-parasitoid-released plots compared with 0.019ą0.046 DBM larvae/leaf in parasitoid-released plots.

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