| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
To develop a biological control based 1PM against Liriomyza leafminers which have developed high resistance to many agrochemicals, an introduction system with natural enemies attacking indigenous leafminer was examined. A total of 15 species was recorded as larval or larval-pupal parasitoid from garden pea leafminer during winter and spring. On the garden pea planted in November, garden pea leafminer increased during the spring when temperature was low, while indigenous natural enemies increased with a raised temperature in May. The parasitism rate of garadepea leafminer by parasitoid wasps increased up to 80% or more in late April. These results suggested that garden pea and its parasitoid system is an ideal mass-production system in nature. The parasitoid fauna varied with time and the position of infested leaves. Among the 15 species recorded from the garden pea leafminer, Chrysocharis pubicornis was dominant species in March, while Diglyphus isaea, Chrysocharis pentheus, and Dacnusa sibirica were dominant in late April and early May. On average, 100 to 300 parasitoid wasps were obtained from 20 garden pea leaves. From these results, we recommended the manual for an introduction of natural enemies from garden pea into vegetable greenhouses and thus the growers intoroduced the system into their own greenhouses. Successful control of leafminer was achieved in 50% of the grower, while 25% failed to control the leafminer. The failure was attributed to an inappropriate method for collecting gardenpea leaves or an misuse of agrochemicals prior to introduction of natural enemies.
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