Effectiveness of a gummies-like diet in retaining flight-controlled adults of the Asian lady beetle, Harmonia axyridis (Coleoptera: Coccinellidae), under laboratory and field conditions

Predacious insects have rarely been implemented for biological pest control in open-field cultivation in Japan, partly because they may be readily dispersed from crops. The Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is an indigenous natural enemy of aphids in Japan. In recent years, technology for establishing lady beetles on plants using an artificial diet has been advanced for greenhouse cultivation. In open-field cultivation, however, there are problems such as deterioration of food quality due to environmental conditions, and this technology has yet to be put to practical use. Flight-controlled adults of the lady beetle are commercially available as ‘Tentrol’ and are utilized for aphid control in Chiba Prefecture. In this study, the effects of a gummies-like diet developed for flight-controlled adults of the lady beetle were examined in laboratory and outdoor experiments. The laboratory findings showed that the gimmies-like diet is more persistent than two commercial diets as food for the beetle. In the outdoor experiment, the diet had a significant effect on retaining the beetles in stocks of eggplants. These results indicate that use of the diet together with flight-controlled lady beetles may be an effective aphid control method in open-field cultivation.