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Abstract Selective insecticide application is one important strategy for more precisely targeting harmful insects while avoiding or mitigating collateral damage to beneficial insects like honey bees. Recently, macrocyclic lactone-class insecticides have been introduced into the market place as selective bio-insecticides for controlling many arthropod pests, but how to target this selectivity only to harmful insects has yet to be achieved. In this study, the authors investigated the acute toxicity of fourmacrocyclic lactone insecticides (commercialized as abamectin, emamectin benzoate, spinetoram, and spinosad) both topically and through feeding studies with adult forager honey bees. Results indicated emamectin benzoate as topically 133.3, 750.0, and 38.3-fold and orally 3.3, 7.6, and 31.7-fold more toxic, respectively than abamectin, spinetoram and spinosad. Using Hazard Quotients for estimates of field toxicity, abamectin was measured as the safest insecticide both topically and orally for honey bees. Moreover, a significant reduction of sugar solution consumption by treatment group honey bees for orally applied emamectin benzoate and spinetoram suggests that these insecticides may have repellent properties.

The aim of the present study was to evaluate the efficacy of some chemical compounds to management rust disease on common bean under greenhouse and field conditions. In vitro, the effect of four chemical compounds, i.e. phosphoric acid at concentrations 0.3 and 0.6%, benzoic acid, Bion® (BTH), and pyrocatechol at concentrations 4 and 8 mM from each, as well as fungicide, Tilt 25%, 0.25 and 0.5 cm3/l water on urediniospores germination of Uromyces appendiculatus was tested on water agar medium. All these compounds decreased the germination of urediniospores percentage. Under greenhouse and field experiments, application of these compounds led to decrease in disease incidence compared to the control treatments. Benzoic acid at 2015 growing seasons was the most effective in reduction of disease incidence more than the other compounds, whereas the disease incidence decreased from 59.92 to 21.43% and from 68.43 to 18.41% under greenhouse and field conditions, respectively.