Life cycle, Ecological Characteristics, and Control of Trachys yanoi (Coleoptera: Buprestidae), an Important Pest of Zelkova serrata.
This study was conducted to elucidate the life cycle and the ecological characteristics ofTrachys yanoiY. Kurosawa, an important pest ofZelkova serrata(Thunb.) Makino. Life cycle, mortality rates in developmental stages, annual population dynamics, and early leaf abscission were investigated. Adults emerged from under the bark ofZelkovatrees in April and fed onZelkovaleaves. Females laid 49 eggs on average, mainly in May and early June. Eggs hatched after 17 days, and the larvae fed inside the leaves. They developed through three instars. In July, leaves with the final stage of larvae were abscised. Four days after abscission, the larvae pupated. New adults eclosed from pupae seven days after pupation, and the adults emerged from abscised leaves after an additional two days. In total, 1650 adults emerged per 1 m² of forest floor, resulting in a major population increase. The newly emerged adults fed on the remainingZelkovaleaves, compounding the damage. In October, adults overwintered under the tree bark. Mortality rates in the egg, larval, and pupal stages were 41%, 58%, and 31%, respectively. The mortality rate among overwintering individuals was 43%. Because onlyZelkovaleaves that were abscised in July contained the larvae, and because only a small number of beetles emerged from non-abscised, mined leaves, the removal of abscised leaves at nine-day intervals over period of early leaf abscission is a simple and effective way to control the beetle.
Yamanashi Forest Research Institute, 2290-1 Saisho-ji, Fujikawa-cho, Minamikoma-gun, Yamanashi 400-0502, Japan. oosawa-ujk@pref.yamanashi.lg.jp.
Masashi
M
Ohsawa
Zelkova serrata; early leaf abscission; insect pest; jewel beetle; leaf miner