The response of pyriproxyfen-resistant and susceptible Bemisia tabaci Genn (Homoptera: Aleyrodidae) to pyriproxyfen and fenoxycarb alone and in combination with piperonyl butoxide
✍ Scribed by Devine, Gregor J; Ishaaya, Isaac; Horowitz, A Rami; Denholm, Ian
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 135 KB
- Volume
- 55
- Category
- Article
- ISSN
- 1526-498X
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✦ Synopsis
Pyriproxyfen was eþ ective against susceptible Bemisia tabaci eggs at a of 0.003 mg LC 50 litre-1 and against nymphs at 0.02 mg litre-1. In comparison, eggs of a laboratory selected, pyriproxyfen-resistant B tabaci strain, originating in an Israeli greenhouse, exhibited 6500-fold resistance and nymphs exhibited 1100-fold resistance. Eggs and nymphs of a strain from an Israeli sunýower üeld exhibited 450 and 210-fold resistance in comparison to the susceptible standard. Fenoxycarb was generally less eþ ective than pyriproxyfen against B tabaci eggs and nymphs but was unaþ ected by pyriproxyfen resistance. Piperonyl butoxide (PB) was antagonistic to pyriproxyfen, and this increased with increasing pyriproxyfen resistance. PB had no eþ ect on the toxicity of fenoxycarb. Collectively, these data imply that the modes of action of pyriproxyfen and fenoxycarb are distinct, despite the structural similarities of these molecules. Possible reasons for the antagonism of PB against pyriproxyfen are discussed.