Increasing rates of parasitism of the larval parasitoid Bracon brevicornis(Hym., Braconidae) by using kairomones, pheromones and a supplementary food

The kairomonal effect of hexane extract of the larvae of Ostrinia nubilalis and Sesamia cretica on Bracon brevicornis adults was evaluated through olf actometer tests. The parasitoid males showed no definite response to any ka iromone. Females were attracted to the kairomone of S. cretica more than to that of O. nubilalis. Highly significant effect of the sex pheromone of O. nubilalis on the females of B. brevicornis was recorded. Kairomones (hexan e extracts of larvae) varied in their effect on the released B. brevicornis parasitoids. The kairomone of S. cretica increased the parasitisation from 7.74 to 17.05%, while the kairomones of O. nubilalis and of Spodoptera lit toralis were not significantly effective. Spraying molasses solution (10%) on the corn stalks before releasing B. brevicornis parasitoids increased th e rate of parasitism from 7.74 to 28.21%. The concentration of 5% gave insi gnificant increase in the parasitisation rate.