title: Field evaluation of resistance to pyriproxyfen in Bemisia tabaci (B biotype).
abstract: We determined effects of aerial sprays of the insect growth regulator pyriproxyfen on sweetpotato whitefly, Bemisia tabaci (Gennadius) (B biotype), in Arizona cotton (Gossypium spp.) fields. We measured survival for males and females from a susceptible strain and a laboratory-selected resistant strain, as well as for hybrid female progeny from crosses between the strains. Insects were exposed directly to pyriproxyfen sprays in the field or indirectly in the laboratory by rearing them on sprayed leaves collected from the field. In all tests, survival was higher for the resistant strain than the susceptible strain, but did not differ between sexes in each strain. Survival to the adult stage did not differ between eggs and nymphs directly exposed to sprays. For susceptible and hybrid individuals, survival was lower on leaves collected the day of spraying than on leaves collected 2 wk after spraying. In contrast, survival of resistant individuals did not differ based on the timing of exposure. Dominance of resistance to pyriproxyfen depended on the type of exposure. Resistance was partially or completely dominant in direct exposure bioassays and on leaves collected 2 wk after spraying (h > 0.6). Resistance was partially recessive on leaves collected the day of spraying (mean h = 0.34). Rapid evolution of resistance to pyriproxyfen could occur if individuals in field populations with traits similar to those of the laboratory-selected strain examined here were treated intensively with this insecticide.
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ 85721, USA. dcrowder@ag.arizona.edu
authors.forename: David W
authors.initials: DW
authors.lastname: Crowder
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Dennehy
authors.forename: Christa
authors.initials: C
authors.lastname: Ellers-Kirk
authors.forename: L Christine M
authors.initials: LC
authors.lastname: Yafuso
authors.forename: Peter C
authors.initials: PC
authors.lastname: Ellsworth
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Tabashnik
authors.forename: Yves
authors.initials: Y
authors.lastname: Carriere
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D006430:Hemiptera / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D006824:Hybridization, Genetic; D007305:Insecticide Resistance / Q000235:genetics; D007306:Insecticides / Q000008:administration & dosage / Q000494:pharmacology*; D007605:Juvenile Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008297:Male; D009758:Nymph / Q000187:drug effects / Q000254:growth & development; D010063:Ovum / Q000187:drug effects / Q000254:growth & development; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology*; D012737:Sex Factors
chemical_list: D007306:Insecticides; D007605:Juvenile Hormones; D011725:Pyridines; C055613:pyriproxyfen