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 µg/g dry mass [SD = 7.55]) of azadirachtin were present in leaves within 7 d 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.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 103 • No. 3