Euseius sojaensis (Ehara) is an effective indigenous natural enemy of some eriophyid mites and spider mites in Japan. However, pesticides that are toxic to it are frequently applied in commercial Japanese pear orchards until early summer, when the predator densities are at their peak. Here, we examined the suppressive effect of inoculative release of E. sojaensis on Eriophyes chibaensis Kadono and Tetranychus kanzawai Kishida under conservation control using selective pesticides from late April to late June. The densities of E. sojaensis peaked in early June. In E. sojaensis-release plots, phytoseiid populations were larger, E. chibaensis and T. kanzawai populations were smaller, and rates of leaf mosaic and russeting caused by E. chibaensis were significantly lower than in control plots. These results suggest that E. sojaensis can control E. chibaensis and T. kanzawai populations simultaneously. As it may be difficult to suppress E. chibaensis densities below the control threshold of 50 mites per leaf only by conservation using selective pesticides, enhancement and augmentation of E. sojaensis for sustainable control of mites should be considered as an option in commercial Japanese pear orchards.

Euseius sojaensis (Ehara) 是日本某些绦虫和红蜘蛛的有效本土天敌。然而，对其有毒的杀虫剂经常用于商业日本梨园，直到初夏，那时捕食者的密度达到顶峰。在这里，我们检查了释放接种式的抑制作用E. sojaensis上瘿螨chibaensis角野和神泽叶螨保护控制下使用选择性杀虫剂岸田从四月下旬至6月下旬。E. sojaensis的密度在 6月初达到顶峰。在E. sojaensis释放地块中，植物血清种群较大，E. chibaensis和T. kanzawaiE. chibaensis引起的叶片花叶和锈蚀率显着低于对照样地。这些结果表明大豆 E. sojaensis可以同时控制E. chibaensis和T. kanzawai种群。由于仅通过使用选择性杀虫剂进行保护可能难以将chibaensis 的密度抑制在每片叶子 50 只螨的控制阈值以下，因此在商业日本梨园中，应考虑增强和增加大豆 E. sojaensis以可持续控制螨虫.