Azadirachtin: An Effective Systemic Insecticide for Control of Agrilus planipennis

Research to determine the efficacy of azadirachtin (TreeAzin), to control emerald ash borer.

"The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive pest discovered in North America in 2002, is now well established and threatens ash (Fraxinus spp.) trees throughout the continent. Experiments were conducted to 1) examine the efficacy of an alternative natural pesticide, azadirachtin, to control emerald ash borer, and 2) determine foliar uptake and dissipation patterns after systemic injections of azadirachtin into trunks of small (2.2 cm diameter at breast height [dbh]), uninfested green ash trees.We found no evidence of mortality of adult beetles. In contrast, fewer larvae completed their development at dose levels 1.7 mg (AI)/cm dbh and development ceased beyond the second instar at dose levels 13.6 mg (AI)/cm dbh. Substantial concentrations (11.2 g/g dry mass [SD 7.55]) of azadirachtin were present in leaves within 7 d[ays] of treatment. After rapid initial uptake, concentrations in leaves declined logarithmically during the 55 d after injection. A similar pattern was observed in a separate experiment that examined the uptake and translocation of azadirachtin in larger green ash trees (22 cm dbh) treated with 250 mg (AI)/cm dbh with the EcoJect injection system. In another experiment, recently infested plantation green ash trees treated with doses 40 mg (AI)/cm dbh had significant reductions in adult emergence 1 yr postinjection. Given the inhibition of larval development, reduction of adult emergence, and the occurrence of foliar residues at biologically active concentrations, we conclude that azadirachtin is effective in protecting ash trees from emerald ash borer." [Abstract]

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