Abstract
Neoseiulus californicus has been increasing in number and geographical distribution since the 1990s in Japan, and is considered to be a new prospective predator species against Panonychus citri on citrus. We investigated the occurrence of N. californicus in citrus orchards with different agrochemical spraying programs in Kyushu district, south-western Japan. The occurrence of N. californicus greatly differed among orchards. In conventional control orchards and agrochemical-reduced orchards, N. californicus females were observed in 50–60% of orchards. On the other hand, N. californicus females were rare in agrochemical-free orchards. N. californicus females were observed in all prefectures in the Kyushu district, but the occurrence of N. californicus was different among the prefectures. In Saga Prefecture, N. californicus females were observed in all conventional control and agrochemical-reduced orchards. In Nagasaki Prefecture, Kumamoto Prefecture, and Miyazaki Prefecture, N. californicus females were observed in 60% or more of the conventional control and agrochemical-reduced orchards. In Fukuoka Prefecture, N. californicus females were abundant in the southern area, whereas no N. californicus females were observed in the northern area. In Oita Prefecture, N. californicus females were observed in only 30.8% of the conventional control and agrochemical-reduced orchards. N. californicus females were rare in Kagoshima Prefecture.
