Comparative laboratory and field study of biorational insecticides for Culicoides biting midge management in larval developmental sites

• Published in: Acta tropica 2019-10, Vol.198, p.105097-105097, Article 105097
• Main Authors: Foxi, Cipriano, Delrio, Gavino, Luciano, Pietro, Mannu, Roberto, Ruiu, Luca
• Format: Article
• Language: English
• Subjects: Animals; BTV; Ceratopogonidae - drug effects; Ecosystem; IGR; Immature midges; Insect Control - methods; Insect Vectors - drug effects; Insect Vectors - growth & development; Insecticides - administration & dosage; Insecticides - chemistry; Insecticides - pharmacology; Larva - drug effects; Larva - growth & development; Microbials; Sheep farm; Soil - chemistry; Water - chemistry
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2019.105097

A selection of biorational insecticides including IGRs, microbials and botanicals, was assayed against Culicoides larvae in the laboratory and in their natural breeding sites. [Display omitted] •A selection of biorational insecticides was assayed on Culicoides larvae.•Active ingredient lethal concentration against biting midges was determined.•IGRs, microbials and botanicals efficacy was assessed in midge breeding sites.•Brevibacillus laterosporus was the most active microbial in the field environment.•Pyriproxyfen and cyromazine showed good efficacy and long-lasting residual effects. An appropriate management strategy of bluetongue vectors should include larvicidal treatments in their larval development sites utilizing active substances with low environmental impact. A selection of biorational insecticides with potential against dipteran larvae was assayed in the laboratory against field collected Culicoides larvae including C. cataneii, C. circumscriptus, and C. imicola, determining their median lethal concentrations in water and mud/water substrate. The efficacy of formulations containing the insect growth regulators pyriproxyfen and cyromazine, the botanical insecticide azadirachtin, and the entomopathogenic bacteria Bacillus thuringiensis israelensis and Brevibacillus laterosporus, was also assessed in field conditions in a comparative study conducted in sheep farm larval development sites, including treatments with the organophosphate temephos. Significant larvicidal properties were associated with the various insecticides evaluated in the laboratory assays and in field trials, although with different levels of effectiveness. While temephos was confirmed to be an effective broad spectrum larvicidal substance, B. laterosporus appeared to be the most effective among entomopathogens, while insect growth regulators combined a good efficacy to a long-lasting residual effect in the field. Everything considered, the use of these biorational insecticides alone or in combination with larval habitat manipulation techniques appears to be a promising method to complement integrated biting midge management programs.