Analysis and evaluation of four fungicides toxicity and sensitivity against two Trichogramma spp.

Four fungicides,triadimefon,trifloxystrobin,prochloraz and phenazino-1-carboxylic acid were tested to determine their toxicity to parasitoid Trichogramma ostrininae and Trichogramma dendrolimi by using dry film bioassay.The results showed that the toxicity of all the fungicides tested to the parasitoid were different.The toxicity of triadimefon to T.ostrininae and T. dendrolimi was the highest one (with LC50 of 0.822 0 and 10.55 mg/L respectively),followed by prochloraz (12.94 and 218.1 mg/L).The LC50 values of trifloxystrobin and phenazino-1-carboxylic acid were 48.70 and 24.25 mg/L to T.ostrininae,180.3 and 240.3 mg/L to T. dendrolimi, respectively,exhibiting low toxicity when compared with others tested.The results suggested T.ostrininae was more sensitive to the fungicides than T. dendrolimi,and the risk of four fungicides exposed to the two Trichogramma was different.It indicated that T. ostrininae was more representative to assess the risk of pesticide to Trichogramma spp.