摘要：

This paper elucidates the effect of different host plants on the area of discovery of the parasitoid Trioxys (Binodoxys) indicus, which decreases linearly with the increase of parasitoid density. This decrease is minimum in aphids reared on Cajanus cajan followed by those reared on Dolichos lablab and Solanum melongena, but the killing power (k value) increases significantly in all the tested host plants, being maximum in aphids reared on C. cajan followed by those reared on D. lablab and S. melongena. However, when the host density increases, the area of discovery and k value (high in C. cajan aphids followed by D. lablab and S. melongena aphids) increases up to 50 hosts and thereafter decreases. The leaf texture of the host plants and the interference between the parasitoids at higher densities is suggested as a cause for this type of behavioural response which is explained by the population model of M. P. Hassell and G. C. Varley. For the suppression of Aphis craccivora population, it is suggested that the parasitoid and the host ratio may be 1:50 and for the mass rearing of the parasitoid, when C. cajan is not available in the field, D. lablab may be used as an alternative host plant.

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