The 2011 ASHS Annual Conference

Sweetpotato Whitefly, Bemisia tabaci are a major pest of 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 and 2009, were 1000 and 1500 per trap, respectively.  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agriculture in the western regions of Yuma influenced whitefly populations immediately adjacent to the city (Bealmear, unpublished 2009).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 movement leads to questions about management.  A survey of pesticides used in Arizona agriculture was done in 1995, while similar chemistries are available for ornamental plants these products were not included in the survey.  In February and March of 2010 a statewide survey was administered to home gardeners to determine which whitefly control products they used.  Two hundred and seventy nine people, mostly homeowners, responded to the survey.  Participants from seven counties indicated whiteflies were pests in their gardens, Yuma residents responded with the highest number.   Nine different products were evaluated for efficacy in July and August of 2010 to see which one had the highest efficacy.  Preliminary data showed that while some products reduced whitefly numbers nothing worked consistently throughout the treatment period.