Effects of providing pollen to Euseius sojaensis or Amblyseius eharai (Acari: Phytoseiidae) on populations of the pink citrus rust mite, Aculops pelekassi (Acari: Eriophyidae)

The pink citrus rust mite, Aculops pelekassi (Keifer) (Acari: Eriophyidae), is a serious pest and is widely distributed in most citrus-growing areas of the world. Euseius sojaensis (Ehara) and Amblyseius eharai Amitai and Swirski (Acari: Phytoseiidae) are indigenous generalist predatory mites in Japanese citrus orchards. Although these two species prey upon some eriophyid mites, A. pelekassi is not considered to be a suitable food for their development and reproduction. In this study, we examined the suppressive effect of these two predators on A. pelekassi density when provided with pine pollen as an alternative food. In a growth chamber experiment, pollen provisioning led to population increase of E. sojaensis and A. eharai, but only E. sojaensis significantly decreased A. pelekassi populations. In a field experiment, E. sojaensis release suppressed A. pelekassi populations on both leaves and fruit. Fruit injury by A. pelekassi in October was suppressed by E. sojaensis release or pollen provision. These results suggest that E. sojaensis can serve as an effective biological control agent against A. pelekassi when provided with pine pollen. Therefore, maintaining populations of E. sojaensis by means such as pollen provisioning could lead to successful biological control of the eriophyid mite in Japanese citrus orchards.