Comparison of attractiveness, suitability for oviposition, and amount of food resources between two varieties of okra as insectary plants of Orius spp. (Hemiptera: Anthocoridae)

Okra Abelmoschus esculentus L. Moench (Malvales: Malvaceae) is expected to act as an insectary plant to conserve and enhance Orius spp. (Heteroptera: Anthocoridae) when planted in open-field cultivations of eggplant. Since it is known that the occurrence of thrips (Thysanoptera: Thripidae) on okra plant is insufficient as their prey, it possibly provides another food resource for these predators. The present study compared some characteristics that positively effect the growth of Orius populations between two varieties of okra: Marumichan and Earlyfive. In the olfactory response test, both Orius sauteri and O. minutus were attracted to volatiles of Earlyfive. In the oviposition test, there was no significant difference in the numbers of eggs laid on the two varieties. In the 2-year field surveys, the seasonal occurrence of thrips was similar on the two varieties, but significantly more Orius spp. occurred on Marumichan than Earlyfive. Also, significantly more pearl bodies, which contain valuable nutrition for insects, was secreted from Marumichan than Earlyfive. From these results, we concluded that the effectiveness of okra as an insectary plant is supported primarily by pearl bodies.