Influence of Pesticide Dose Preparation on Toxicity of Honeybee Species, Apis mellifera L. by Contact Method

The aim of this study was to compare the effect dose prepared from two different stocks in an acute contact toxicity test honeybees, Apis mellifera L under laboratory condition. Dimethoate 30% EC contains active ingredient 90.18 % w/w which used as substance. conducted per OECD Guideline 214 (1998). stock solution 69.92 ppm (Stock I) and 4.3ppm II) were deionized water. evaluated against honeybees at doses viz., 0.045, 0.068, 0.101, 0.152 0.228 µg a.i./bee both solutions. Bees treated with dissolved water dosed by topical application on dorsal side thorax each bee. control (Deionized water) maintained for comparison. Assessments mortality abnormal behavioural effects carried out 4, 24 48 hours after dosing. highest tested nominal recorded 70% lowest 0.045 0% Whereas dimethoate 23.33% 48-hour Contact LD50 0.160 (95% Confidence limits: 0.135 - 0.201) dimethoate/bee 0.319 All groups 0.0% during assessment made up Observations sublethal (abnormal behavioural) included moribund, knockdown apathy dosing No sub lethal observed 4 met all validity criteria described 214.