Systemic slow-release neem formulations: the future of cabbage aphids, Brevicoryne brassicae control

The efficacy and dose-response, residual effect, and effect on the fecundity of neem formulations on cabbage aphid Brevicoryne brassicae applied systemically through root tissues of Brussels sprouts (Brassica oleracea), were studied in the greenhouse. Two formulations were tested; NeemAzal granules containing 7% azadirachtin (AZA), at 75, 150, 225 and 300 mg per kilogram of the substrate and a water-based formulation, NeemAzal-T (1% AZA) at 1, 1.5, 2 and 2.5 ml/kg of substrate. The efficacy of the neem formulations was dose-dependent, with the highest doses of NeemAzal granules and NeemAzal T, (300 mg and 2.5 ml/kg of substrate) respectively, having up to 0% survival of aphids by 14 days after treatment. The manufacturer’s recommended doses, NeemAzal granules at 150 mg and NeemAzal-T at 1 ml/kg of substrate, were used to evaluate the persistence and bioresidual effect of the azadirachtin on cabbage aphid over time. After treatments, plants were infested with one-day-old aphid larvae on the same day (D0), three days (D4) and eight days (D8) after treatment. There was a sharp decrease in persistence with NeemAzal-T when plants were infested 8 days after treatment, and there was no significant difference in the survival of aphids with control plants. However, there were no differences in the survival rate of cabbage aphid larvae if exposed 0, 4 or 8 days after treatment with NeemAzal granules but the survival rate was significantly lower compared to that in the control. The fecundity of aphids decreased significantly after the application of azadirachtin. In conclusion, results show high efficacy of soil-applied NeemAzal against cabbage aphid, with NeemAzal granules, which is a slow-release formulation, giving the longest period of bioactivity hence offering the longest period of protection

Additive and synergistic interactions amongst Orius laevigatus (Heteroptera: Anthocoridae), entomopathogens and azadirachtin for controlling western flower thrips (Thysanoptera: Thripidae)

This study evaluated the efficacy of the foliage-dwelling predator Orius laevigatus, soil applied entomopathogens and azadirachtin alone and in combinations for controlling western flower thrips (WFT). Evaluated products were Nemastar®Steinernema carpocapsae (E-nema) and O. laevigatus (Re-natur), Metarhizium anisopliae isolate ICIPE-69 and NeemAzal-T (azadirachtin) (Trifolio). Efficacy against WFT was significantly improved by combined treatments achieving 62–97 % reduction in WFT emergence, compared to 45–74 % in single treatments, and interactions resulted in two synergistic and eight additive responses. Metarhizium-based treatments reduced WFT survival by 93–99.6 % when late mortality by mycosis was considered. Halving the number of released predators did not significantly reduce efficacy (86–96 vs. 76–88 % thrips reduction), and when Orius was introduced to target L1 of WFT, 96–98 % reduction was achieved while only 71–89 % for L2. Early release of O. laevigatus and combination with soil application of NeemAzal-T and/or entomopathogens can be a successful and reliable biocontrol strategy for WFT

Pauli Biographical Collection: Letter

H. Pallmann asks W. Pauli about some biographical information