Potential Adaptation Of A Q Biotype Whitefly Population From Poinsettia To Field Crops

The invasive Q biotype whitefly was first detected in the US on poinsettia in 2004 and is still not a pest outside of greenhouse environments in the US. To assess the potential for the establishment of the Q biotype on field crops, population cage experiments were conducted to compare the performance of a poinsettia-derived Q population named P06 on poinsettia and six field crops (alfalfa, tomato, melon, cotton, cowpea and cabbage). P06 adults reared on poinsettia as nymphs laid eggs on all six field crops. Significantly more eggs were laid on alfalfa, tomato, melon and cotton than on cabbage, cowpea and poinsettia. These eggs hatched and the nymphs developed to adults on the six field crops. Relative to poinsettia, whitefly survival was similar on cowpea, alfalfa, tomato and cabbage, but significantly higher on cotton and melon. Moreover, P06 had significantly shorter development times from egg to adult on cotton, melon, cowpea, tomato and alfalfa than they did on poinsettia. However, the F1 adults raised on the six field crops had significantly shorter lifespans and laid 11- to 18-fold fewer eggs than did the F1 adults raised on poinsettia. Taken together, while P06 may have some potential to establish on field crops, the shorter lifespans and extremely low fecundities of the F1 adults raised on the six field crops suggests that P06 is incapable of rapidly adapting to them. Poor adaptation to field crops may explain, at least partially, why the Q biotype has not established in the US field system.