Mites (Acari) infesting stored animal feed products in northern Thailand

Storage mites are serious pests of stored animal feeds and animals that consume mite-infested feed could reduce feed intake and eventually cause weight loss. To understand the mite species and infestation rates of them in animal feeds, we conducted a survey of mite infestations in samples of animal feeds from animal feed shops, feed mills, or chicken farms in eight provinces in northern Thailand. High mite infestation rates were observed in chicken feed (42.9%), followed by pig feed (26.7%). No mites were observed in fish and frog feeds. Mites were common in pelleted feeds (n = 96) or raw materials (n = 3), but was never observed in extruded feeds (n = 33). The mite species identified include three storage mites: Suidasia pontifica, Dermatophagoides farinae, and Aleuroglyphus chinensis, as well as the predatory mites Cheyletus malaccensis, Blattisocius keegani, and B. everti. Among them, A. chinensis and B. everti, are newly recorded in Thailand. Suidasia pontifica was dominant in chicken and pig feeds, and could be the major storage mite pest in northern Thailand. Figures and identification keys are provided.