Toxicity of dimethoate and fenoxycarb to honey bee brood (Apis mellifera), using a new in vitro standardized feeding method.
A new in vitro method was devised to assess the effects of pesticides on honey bee brood. The method allowed the quantification of doses ingested by larvae and the assessment of larval and pupal mortality. Larval mortality in control samples was lower than 10%. Two active substances were tested: dimethoate and fenoxycarb. The LD(50) of dimethoate was 1.9 microg larva(-1) 48 h after oral exposure of larvae at day 4. Additional dose-related effects on pupal mortality were noted. After a chronic intoxication, the NOAEC (No Observed Adverse Effect Concentration) for larval mortality at day 7 was 2.5 mg kg(-1), whereas a NOAEC of 5 mg kg(-1) was found at day 22 for delayed effects on the reduction of adult emergence. Fenoxycarb applied at day 4 showed no effect on larvae, whereas emergence of adults was affected at doses higher than 6 ng larva(-1).
Aupinel
Pierrick
P
Unité Expérimentale d'Entomologie INRA Le Magneraud, BP 52-17700, Surgères, France. pierrick.aupinel@magneraud.inra.fr
Fortini
Dominique
D
Michaud
Bruno
B
Marolleau
Franck
F
Tasei
Jean-Noël
JN
Odoux
Jean-François
JF
D000818:Animals; D001516:Bees / Q000187:drug effects* / Q000254:growth & development; D004117:Dimethoate / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D009026:Mortality; D048448:Phenylcarbamates / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods*; D023382:Toxicity Tests, Acute / Q000379:methods; D036401:Toxicity Tests, Chronic / Q000379:methods
D007306:Insecticides; D048448:Phenylcarbamates; C052034:fenoxycarb; D004117:Dimethoate