Indigenous natural enemies of Orius sauteri and Orius strigicollis can suppress the population density of Thrips palmi which is the most severe insect pest on eggplants. When eggplant fields are surrounded by sorghums for windbreak, these windbreak sorghums protect the eggplants from being damaged by the thrips flying from outside the fields. Moreover, the sorghums are useful as insectary plants for indigenous natural enemies against major insect pest Aphis gossypii on eggplant. This IPM program for eggplants cultivated in open fields was named ‘Roji Nasu Shoheki Saibai: Cultivation system of eggplants in open fields surrounded by windbreak sorghum’, and this cultivation method has been in practical use for about 20 years ago. Management of the surrounding vegetation is an important technology to enhance the activity of the natural enemies. Therefore, we studied on cultivation characteristics of many horticultural wildflower species and selected some candidate species for insectary plants. About ten years ago, an IPM program for greenhouse eggplant in Okayama Prefecture was proposed based on the results of our studies, and the successful IPM program of greenhouse eggplant in Kochi Prefecture using indigenous natural enemy Nesidiocoris tenuis with its insectary plants. Recently, this IPM program has been implemented for all greenhouse eggplants in our prefecture. Through these IPM programs, the amount of chemical pesticides used in both open field and greenhouse eggplant cultivations has been greatly reduced.
