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The development, feeding behavior, fecundity, and longevity of Delphastus pusillus (LeConte) on the whitefly Bemisia tabaci (Gennadius) was studied in the laboratory at 28 ± 3°C. Developmental time from oviposition to eclosion was 21.0 d. Longevity of adults was 60.5 d for females and 44.8 d for males. Larval and adult beetles fed on all stages of whitefly. The number of prey consumed by adult beetles decreased with increasing age and size of prey; i.e., 167.1 eggs or 11.6 early fourth instars per day. Handling time increased with stage of whitefly, from 31.3 s for eggs to 377.7 s for early fourth instars. Beetle larvae began feeding upon hatching and consumed a mean of 977.5 eggs before pupating. Mated females laid eggs only when reared on diets containing whitefly eggs. When reared exclusively on a diet of eggs, beetles laid 3.0 eggs per day. Mean lifetime egg production was 183.2. Predation on B. tabaci eggs and beetle oviposition was also observed in a greenhouse; mean prey consumption was 51% greater and mean daily oviposition by females was 103% higher than in the laboratory. Between 100 and 150 whitefly eggs per day were required to initiate and sustain oviposition in the laboratory and the greenhouse. The need for large numbers of whitefly eggs in the diet suggests D. pusillus will maintain itself without augmentation only in large populations of B. tabaci.

After the 2004 discovery of the Bemisia tabaci (Gennadius) (Hemiptera Aleyrodidae) Q biotype in the United States, there was a vital need to determine the geographical and host distribution as well as its interaction with the resident B biotype because of its innate ability to rapidly develop high-level insecticide resistance that persists in the absence of exposure. As part of a coordinated country-wide effort, an extensive survey of B. tabaci biotypes was conducted in North America, with the cooperation of growers, industry, local, state, and federal agencies, to monitor the introduction and distribution of the Q biotype. The biotype status of submitted B. tabaci samples was determined either by polymerase chain reaction amplification and sequencing of a mitochondrial cytochrome oxidase I small subunit gene fragment and characterization of two biotype discriminating nuclear microsatellite markers or esterase zymogram analysis. Two hundred and eighty collections were sampled from the United States, Bermuda, Canada, and Mexico during January 2005 through December 2011. Host plants were split between ornamental plant and culinary herb (67%) and vegetable and field crop (33%) commodities. The New World biotype was detected on field-grown tomatoes (Solanum lycopersicum L.) in Mexico (two) and in commercial greenhouses in Texas (three) and represented 100% of these five collections. To our knowledge, the latter identification represents the first report of the New World biotype in the United States since its rapid displacement in the late 1980s after the introduction of biotype B. Seventy-one percent of all collections contained at least one biotype B individual, and 53% of all collections contained only biotype B whiteflies. Biotype Q was detected in 23 states in the United States, Canada (British Columbia and Ontario territories), Bermuda, and Mexico. Forty-five percent of all collections were found to contain biotype Q in samples from ornamentals, herbs and a single collection from tomato transplants located in protected commercial horticultural greenhouses, but there were no Q detections in outdoor agriculture (vegetable or field crops). Ten of the 15 collections (67%) from Canada and a single collection from Bermuda contained biotype Q, representing the first reports of biotype Q for both countries. Three distinct mitochondrial haplotypes of B. tabaci biotype Q whiteflies were detected in North America Our data are consistent with the inference of independent invasions from at least three different locations. Of the 4,641 individuals analyzed from 517 collections that include data from our previous work, only 16 individuals contained genetic or zymogram evidence of possible hybridization of the Q and B biotypes, and there was no evidence that rare hybrid B-Q marker co-occurrences persisted in any populations.

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