title: Assessment of toxicity risk of insecticides used in rice ecosystem on Trichogramma japonicum, an egg parasitoid of rice lepidopterans.
abstract: Both chemical and biological methods are essential for control of insects, for example, lepidopterans, on rice. Thus, it is important to know the effect of chemicals on the biological control agents. In this study, we assessed the toxicity of commonly used insecticides on a biological control agent, Trichogramma japonicum Ahmead (an egg parasitoid of rice lepidopterans) by using a dry film residue method. Results showed that thirty insecticides from seven chemical classes exhibited various degree of toxicity to this parasitoid. Among the seven classes of chemicals tested, organophosphates (chlorpyrifos, fenitrothion, phoxim, profenofos, and triazophos) and carbamates (carbaryl, carbsulfan, isoprocarb, metolcarb, and promecarb) exhibited the highest intrinsic toxicity to T. japponicum, with an LC50 of 0.035 (0.029-0.044) to 0.49 (0.34-0.87) mg active ingredient (a.i.) L(-1), followed by antibiotics (abamectin, emamectin benzoate, and ivermectin), phenylpyrazoles (butane-fipronil, ethiprole, and fipronil), pyrethroids (cyhalthrin, cypermethrin, fenpropathrin, and lambda-cyhaothrin), and neonicotinoids (acetamiprid, imidacloprid, imidaclothiz, nitenpyram, thiacloprid, and thiamethoxam). Moreover, the insect growth regulator insecticides (chlorfluazuron, fufenozide, hexaflumuron and tebufenozide) exhibited the lowest toxicity to the wasps with an LC50 of 3,383 (2406-5499) to 30206 (23107-41008) mg ai. L(-1). Risk quotient analysis showed that phenylpyrazoles, pyrethroids, insect growth regulators, neonicotinoids (with the exception of thiamethoxam), and antibiotics (with the exception of abamectin) are classified as safe agents to the parasitoid, while organophosphates and carbamates are classified as slightly, moderately, or highly toxic agents to the parasitoid. The data presented in this paper provided useful information on the selection of compatible insecticides with T. japonicum.
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Xueping
authors.initials: X
authors.lastname: Zhao
authors.forename: Changxing
authors.initials: C
authors.lastname: Wu
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Cang
authors.forename: Liping
authors.initials: L
authors.lastname: Chen
authors.forename: Ruixian
authors.initials: R
authors.lastname: Yu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000818:Animals; D061046:Biological Control Agents; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000145:classification / Q000633:toxicity*; D007928:Lethal Dose 50; D009036:Moths / Q000469:parasitology; D012275:Oryza; D018570:Risk Assessment; D018675:Toxicity Tests / Q000379:methods*; D014863:Wasps / Q000187:drug effects*
chemical_list: D061046:Biological Control Agents; D007306:Insecticides