Abstract
We devised a method for estimating the initial time of appearance of the first-generation nymphs of the brown-winged green bug, Plautia crossota stali, in Japanese cypress forests. Almost all hatchlings from egg batches inoculated on Japanese cypress in early June died in the second stadium, whereas the mortality rate of the second instar nymphs decreased and the adult eclosion rate increased after late June. The survival rates of the second stadium nymphs experimentally reared on cypress cones collected from the forests increased after late June or mid July depending on the year. These findings indicate that the time cypress cones become effective as food differes from year to year. As a result, the initial appearance of P. crossota stali nymphs in the forests coincides with the time when the cypress cones become effective as a food source.
