Maintained Establishment of Flight-controlled Harmonia axyridis on Open-field Eggplant Surrounded by Sorghum and Its Migration between the Two Plant Species

Abstract

Harmonia axyridis (Pallas) is known as a predator of aphids with high predation ability. On the other hand, it is difficult to use this lady beetle in open fields without flight control because its adults have a high potential of flight ability, they escape from the fields just after release. In this study, we released flight-controlled adults of H. axyridis that had the elytra glued by hot melt adhesive in an open field of eggplant surrounded with sorghum plants and investigated its establishment rate and migration between the two plant species. The establishment rate of flight-controlled H. axyridis on eggplant and sorghum was significantly higher than that of flyable lady beetle. Similarly, the control effect of flight-controlled lady beetle on Aphis gossypii attacking eggplant was significantly higher than that of flyable individuals. Migration of flight-controlled lady beetles between eggplant and sorghum was more enhanced especially in the experimental section II with cucumber cultivation net, compared to the section I without the net.