The 2010 ASHS Annual Conference

Sweetpotato Whitefly, Bemisia tabaci is a major pest of both ornamental and agricultural crops in Arizona. They cause injury such as leaf curl, sooty mold as well as transmit viruses that cause plant death. A recent whitefly dispersal study, conducted in Yuma County, reemphasized that whiteflies are considered major pests between June and October. Average whitefly trap counts for this time in 2008 was 1000 per trap and for 2009 1500 per trap. A comparison of populations between the City of Yuma and surrounding agricultural areas found that agriculture in the western regions of Yuma influenced whitefly populations immediately adjacent to the city (Bealmear, unpublished 2009). This interaction in urban whitefly dispersal leads to questions about their management. A survey of pesticides used in Arizona agriculture was done when the efficacy of pyrethroid insecticides began to diminish in 1995. Similar chemistries are available for ornamental plants but were not included in this survey leaving questions as to which products are being used to control whiteflies on ornamental plants. In February and March of 2010 a statewide survey was administered to home gardeners to determine which whitefly control products are in use. Two hundred and seventy nine people, mostly homeowners, responded to the survey. Sixty seven percent indicated that they do have whitefly problems. Eighty two percent of these indicated the worst problems were on garden and landscape plants. The majority, sixty eight percent responded they do nothing to control whiteflies. Only six percent used pesticides and of those that used pesticides ten percent used products such as malathion, ortho, specticide and sevin. Fourteen percent used biorational products like garden safe, pyrethrins and Bacillus thuringiensis. These results show that whiteflies are a major pest the majority of homeowners do not manage them.