title: Toxicity of Insecticides Targeting Rice Planthoppers to Adult and Immature Stages of Trichogramma chilonis (Hymenoptera: Trichogrammatidae).
abstract: Planthopper-targeting insecticides, pymetrozine, thiamethoxam, buprofezin, and nitenpyram, were tested under laboratory conditions for toxicity to adults and immatures of Trichogramma chilonis Ishii, using standard tests described by International Organization for Biological Control (IOBC). In the dry film residue test, all insecticides resulted in >90% mortality in T. chilonis adults and were ranked as moderately harmful. Persistent toxicity tests revealed that nitenpyram was short-lived and the other three insecticides were of slightly persistent toxicity to the wasp adults. Effects of the insecticides on egg, larval, and prepupal stages of T. chilonis were investigated with striped stem borer as host. At the three stages of T. chilonis (within the host egg), all the insecticides reduced parasitism rate, but nitenpyram and pymetrozine applied at egg stage, buprofezin and nitenpyram at larval stage, and buprofezin and thiamethoxam at prepupal stage of T. chilonis reduced parasitism by <30% in comparison with the control, and were thus ranked as harmless. Although insecticide treatment of the three immature stages of T. chilonis all reduced wasp emergence from host eggs, only thiamethoxam applied at larval stage and buprofezin at prepupal stage resulted in >30% reduction in emergence rate as compared with the control and were categorized as harmful. Immature duration of T. chilonis was only significantly extended by nitenpyram applied to egg stage than the control. Sex ratio of emerged wasps was not affected by the treatment to immature stages. The data are of significance for IPM programs incorporating inundative release of T. chilonis for control of lepidopteran rice pests where there is heavy co-occurrence of planthoppers.
authors.affiliation: State Key Laboratory for Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Ko
authors.initials: K
authors.lastname: Ko
authors.affiliation: State Key Laboratory for Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Yudi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China. mlhou@ippcaas.cn.
authors.forename: Maolin
authors.initials: M
authors.lastname: Hou
authors.affiliation: CABI Switzerland, Rue des Grillons 1, CH-2800, Delémont, Switzerland.
authors.forename: Dirk
authors.initials: D
authors.lastname: Babendreier
authors.affiliation: MOA-CABI Joint Laboratory for Bio-safety, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Dryland Farming Institute, Hebei Academy of Agricultural and Forestry Sciences, Hengshui 053000, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Song
mesh_terms: D000818:Animals; D005260:Female; D007306:Insecticides; D007814:Larva; D008297:Male; D010063:Ovum; D010572:Pest Control, Biological; D023382:Toxicity Tests, Acute; D014863:Wasps
chemical_list: D007306:Insecticides
keywords: biological control; compatibility; egg parasitoid; neonicotinoid; pyridine