Integration of <i>Orius nagaii</i> (Yasunaga) (Hemiptera: Anthocoridae) and eco-friendly insecticide to improve <i>Dendrothrips minowai</i> (Priesner) (Thysanoptera: Thripidae) control

Combined use of eco-friendly insecticides with natural enemies is increasingly being used in pest management. In this study, the combination of eco-friendly insecticides and Orius nagaii (Yasunaga) (Hemiptera: Anthocoridae), an important predator of the thrips, in controlling Dendrothrips minowai (Priesner) (Thysanoptera: Thripidae), a major tea pest, was evaluated in both laboratories and tea plantations. Five commercial insecticides were first screened the toxicity to D. minowai, and their safety to O. nagaii. The results showed mineral oil and Metarhizium anisopliae CQMa421 were toxic against D. minowai, while diafenthiuron, mineral oil and M. anisopliae CQMa421 were relatively safe for O. nagaii. Sublethal bioassay on eggs, nymphs, and adults of O. nagaii showed that mineral oil exposure minimized hatching rate among the 5 insecticides. The adverse effects of diafenthiuron and M. anisopliae CQMa421 on the development and reproduction of O. nagaii were inferior to those of spinetoram and indoxacarb. Both spinetoram and indoxacarb displayed significant acute and sublethal effects on O. nagaii. Field trials unveiled that the combined use of O. nagaii and diafenthiuron was an effective and lasting pest control strategy against D. minowai. The results contribute to an improved D. minowai management coordinated eco-friendly insecticide with natural enemy insects.