title: Risk assessment of various insecticides used for management of Asian citrus psyllid, Diaphorina citri in Florida citrus, against honey bee, Apis mellifera.
abstract: The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus trees worldwide. A wide variety of insecticides are used to manage D. citri populations within citrus groves in Florida. However, in areas shared by citrus growers and beekeepers the use of insecticides may increase the risks of Apis mellifera  L. (Hymenoptera: Apidae) loss and contaminated honey. The objective of this research was to determine the environmental toxicity of insecticides, spanning five different modes of action used to control D. citri, to A. mellifera. The insecticides investigated were imidacloprid, fenpropathrin, dimethoate, spinetoram and diflubenzuron. In laboratory experiments, LD50values were determined and ranged from 0.10 to 0.53 ng/μl for imidacloprid, fenpropathrin, dimethoate and spinetoram. LD50values for diflubenzuron were >1000 ng/μl. Also, a hazard quotient was determined and ranged from 1130.43 to 10893.27 for imidacloprid, fenpropathrin, dimethoate, and spinetoram. This quotient was <0.447 for diflubenzuron. In field experiments, residual activity of fenpropathrin and dimethoate applied to citrus caused significant mortality of A. mellifera 3 and 7 days after application. Spinetoram and imidacloprid were moderately toxic to A. mellifera at the recommended rates for D. citri. Diflubenzuron was not toxic to A. mellifera in the field as compared with untreated control plots. Phenoloxidase (PO) activity of A. mellifera was higher than in untreated controls when A. mellifera were exposed to 14 days old residues. The results indicate that diflubenzuron may be safe to apply in citrus when A. mellifera are foraging, while most insecticides used for management of D. citri in citrus are likely hazardous under various exposure scenarios.
authors.affiliation: Entomology and Nematology Department, University of Florida, Citrus Research and Education Center, 700 Experiment Station Rd, Lake Alfred, FL, 33850, USA. xuedongchen@ymail.com.
authors.forename: Xue Dong
authors.initials: XD
authors.lastname: Chen
authors.affiliation: Entomology and Nematology Department, University of Florida, Citrus Research and Education Center, 700 Experiment Station Rd, Lake Alfred, FL, 33850, USA.
authors.forename: Torrence A
authors.initials: TA
authors.lastname: Gill
authors.affiliation: Entomology and Nematology Department, University of Florida, Citrus Research and Education Center, 700 Experiment Station Rd, Lake Alfred, FL, 33850, USA.
authors.forename: Kirsten S
authors.initials: KS
authors.lastname: Pelz-Stelinski
authors.affiliation: Entomology and Nematology Department, University of Florida, Citrus Research and Education Center, 700 Experiment Station Rd, Lake Alfred, FL, 33850, USA.
authors.forename: Lukasz L
authors.initials: LL
authors.lastname: Stelinski
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D002957:Citrus; D004132:Diflubenzuron / Q000633:toxicity; D004117:Dimethoate / Q000633:toxicity; D054750:Ecotoxicology; D006430:Hemiptera / Q000502:physiology*; D007093:Imidazoles / Q000633:toxicity; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000633:toxicity*; D018942:Macrolides / Q000633:toxicity; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity; D018570:Risk Assessment; D018675:Toxicity Tests
chemical_list: D007093:Imidazoles; D007306:Insecticides; D018942:Macrolides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011722:Pyrethrins; C082359:imidacloprid; C044267:fenpropathrin; D004132:Diflubenzuron; D004117:Dimethoate; C548262:spinetoram
keywords: Acute toxicity; Apis mellifera; Chronic toxicity; Diaphorina citri; Insecticide mode of action; Phenoloxidase activity