Gotoh, T., 1987.
Intraleaf distribution of Panonychus ulmi (Koch) (Acarina: Tetranychidae) on dwarf bamboo. Applied Entomology and Zoology, 22: 248-258.
Abstract
Seasonal, diel changes in the intraleaf distribution of populations of Panonychus ulmi were studied throughout its life cycle on dwarf bamboo (Sasa senanensis) in Japan in 1983-84. The tetranychid overwintered in the egg stage on leaves, and most of the eggs hatched in early (1983) or late (1984) May. Four or 5 generations occurred before late October or early November. Non-diapause eggs, active immature stages and adult females were found predominantly on the uppersurface of the leaf, except during periods of low temperature or cloudy conditions. About half of the active stages that did populate the undersurface of the leaf were found predominantly near the leaf edge, though they were unable to feed on this surface. It was thought likely that these stages moved frequently from the under to the uppersurface to feed and that the undersurface served as a refuge from severe environmental factors. Diapause eggs, quiescent stages and adult males were mainly found on the leaf undersurface. The position of the active stages changed daily on the leaf surfaces: in the daytime they appeared on the uppersurface of the leaves, whereas at night they were found on the undersurface. It appeared that these movements are controlled by a complex interaction among light intensity, air temperature and relative humidity
