Abstract
The authors investigated the life history and seasonal prevalence of theGeoblissus hirtulusBurmeister, as well as damage to turfgrass grounds in golf courses built on the sand hill, during the period from November, 1977 through December, 1978. The results are summarized as follows:
1. The damage to turfgrass by this insect occurs on the slopes facing to the south in the sand or sandy soil area. First, due to the underground part of turfgrass sapped by this insect, the stems and leaves on the ground wither, and subsequently the subterranean stems are exposed in the form of fiber by an outflow of soil. Such damage continues from the latter part of August to next May, with progressive spread of the damaged area.
2. Adults were distinguished into male and female according to shape of the genital segment in their abdomen. In this experiment, the average number of eggs laid is 4.1. This would be because the adults that oviposit in Petri dishes are short-lived. The length of the oviposition period is 4.5 days.
3. Eggs average 0.92 mm in longer diameter and 0.45 mm in shorter one, and no absorptive growth is observed. The lengths of egg stage at 20°C, 25°C, and room temperature are 30.5, 17.6 and 18.4 days, respectively, with the good percentage of egg hatch.
4. During the period of larval hatch continuing from June to September, the larvae grow gradually and molt five times. New adults emerge in and after August. Almost all adults winter except some cases of wintering at the larval stage. It is generally supposed that the adults after wintering begin to oviposite in the middle part of next May.
