Background: The insect growth regulator pyriproxyfen has provided effective control of the whitefly Bemisia tabaci Gennadius in many countries. Here, whether or not fitness costs were associated with pyriproxyfen resistance in a laboratory-selected resistant strain (QC02-R) of the B biotype was determined.
Results: Mortality caused by pyriproxyfen and fitness traits over time were measured in unselected and selected hybrid strains, which were created by crossing individuals of the resistant strain with individuals of a susceptible strain. Fitness costs were not associated with resistance in QC02-R, as mortality caused by pyriproxyfen did not increase over time in unselected hybrid strains and fitness traits were similar in unselected and selected hybrid strains. Using a new method to examine the inheritance of resistance, based on data from fitness cost experiments, it was estimated that pyriproxyfen resistance is controlled by two loci in the QC02-R strain.
Conclusion: The lack of fitness costs associated with pyriproxyfen resistance could promote the evolution of resistance in field populations with similar traits to QC02-R.
2008 Society of Chemical Industry