2009 Annual Report
In addition to monitoring resistance to existing commercial compounds, newer experimental chemistry is also being tested to establish baseline responses of whitefly populations. Spirotetramat and pyrifluquinazon are two new insecticides for which baseline bioassays have been conducted over the past two years and continuing to 2009. Commercial registration for spirotetramat in certain crops began in 2008 as demand is increasing for this highly effective insecticide, a lipid synthesis inhibitor that impairs growth and development. In contrast, the mode of action for pyrifluquinazon is not known, yet this compound has a powerful impact on adult whiteflies in lab bioassays and is able to disrupt transmission of plant viruses. We have demonstrated translaminar properties by pyrifluquinazon that translates to long residual activity against whitefly adults. We will soon be testing field-collected samples of adult whiteflies for laboratory bioassay testing that will begin to build the baseline profile for this compound.
Other activities conducted in 2009 include extensive testing of vine mealybug populations infesting grape vineyards throughout much of California. The pest status of this insect continues to grow as more vineyards become infested and the magnitude of infestations increases. This is placing greater pressure on insecticides for managing infestations. Results from 2009 early summer indicate good efficacy by many compounds in controlled bioassays, yet control in the field is not always adequate. This points to the difference between a bioassay result and a field result using the same concentration of a given insecticide. The nature and degree of exposure between the two are likely much different and often incomparable. However, by maintaining constant bioassay conditions, susceptibility changes through time will be revealed in the controlled bioassay and serve as a mechanism for monitoring insecticide resistance.
ADODR monitors progress by site visit and email.