Abstract
The effectiveness of biological control against Liriomyza trifolii (Burgess) by release of the parasitoids, Hemiptarsenus varicornis (Girault), on cherry tomatoes in greenhouses was evaluated. H. varicornis were released 5 times after planting at release rates of 0.33 and 0.16 females per plant in greenhouses from May to June. The density of leafminer larvae at the peak of the occurrence in 0.33 and 0.16 females per plant greenhouses and the control greenhouse were 2.8, 15.9 and 23.6 per leaf, respectively. The density of mines in 0.33 and 0.16 females per plant greenhouses and the control greenhouses were 6.2, 32.2 and 38.0 per leaf, respectively. The percentage of parasitism in 0.33 and 0.16 females per plant greenhouses were 43.7 and 4.8% at 3 weeks after the first release, and were 80.3 and 73.1% at 4 weeks after the first release, respectively. Although H. varicornis was the primary dominant species in the former period, indigenous parasitoids considered hyperparasites to H. varicornis were dominant species in the late period. These results suggest that biological control by H. varicornis against L. trifolii was practically effective on tomatoes in greenhouses.
