Expanded distribution of the bamboo spider mite, Schizotetranychus longus (Acari : Tetranychidae), and predation by Neoseiulus fallacis (Acari : Phytoseiidae)

Schizotetranychus longus Saito is a common pest of bamboo in Japan. We repo rt its new occurrence in the Willamette Valley, Oregon, on bamboo. We asses sed the ability of adult females of Neoseiulus fallacis (Garman), a native predaceous mite, to invade S. longus nests after construction times of 5 or 10 days. Frequency of predators in nests decreased from 5 to 10 days, alth ough the predator laid most of its eggs in nests irrespective of constructi on time. In choice tests, spider mile webbing was more attractive to A! fal lacis than eggs, but similar to feces. Predators searched more in proximity to feces than eggs, but resting sites were equally common near both. Survi val, activity and reproduction of N. fallacis when given ex:cess of mixed l ife stages of S. longus, Tetranychus urticae Koch, pollen of Tulipa gesneri ana L. or Pseudotsuga menzesii (Mirbel), or no food were measured by holdin g single adult female N; fallacis for 7 days. Survival, activity, ovipositi on and immature production of predators were alike for both spider mites, b ut lower (or higher activity) with pollens or when starved. To see if IV; f allacis would suppress S. longus under normal growing conditions, predators were added to infested Sasaella hidaensis (Makino and Uchida) var. 'Murai' plants, and mites were monitored thereafter for 5 weeks. N: fallacis signi ficantly reduced levels of S. longus and the rates that it infested bamboo leaves; it nearly eliminated S. longus from plants at the end of the test.