Incidence and characterisation of resistance to neonicotinoid insecticides and pymetrozine in the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae).
BACKGROUND
Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread.


RESULTS
Mortality rates of UK and European strains of T. vaporariorum to a range of neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates.


CONCLUSIONS
This study indicates strong parallels in the phenotypic characteristics of neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms.
Karatolos
Nikos
N
Rothamsted Research, Harpenden, Hertfordshire, UK. nikolaos.karatolos@bbsrc.ac.uk
Denholm
Ian
I
Williamson
Martin
M
Nauen
Ralf
R
Gorman
Kevin
K
D000818:Animals; D006430:Hemiptera / Q000187:drug effects*; D007093:Imidazoles / Q000494:pharmacology*; D007300:Insect Control; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000494:pharmacology*; D009758:Nymph / Q000187:drug effects; D010935:Plant Diseases / Q000469:parasitology; D014227:Triazines / Q000494:pharmacology*
D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D014227:Triazines; C082359:imidacloprid; C480311:pymetrozine