Predaceous arthopods of the sweetpotato whitefly, Bemisia tabaci (Gennadius), on tomatoes in Florida.

摘要

Field and laboratory studies were undertaken to ascertain the extent of arthropod predation of Bemisia tabaci (Gennadius) (recently reported as a new species, B. argentifolii Bellows & Perring) on tomatoes in Florida. The suitability of the whitefly as prey and olfactory responses to attractant/food supplements for selected predators was investigated.; At least 19 species of arthropods were observed in the laboratory or the field to feed on one or more lifestages of B. tabaci. Field populations of the whitefly and predaceous arthropods were monitored for two years on tomatoes using a whole plant method of sampling. Among the species previously observed to prey on whiteflies, an anthocorid, Orius insidiosus (Say), and a chrysopid, Ceraeochrysa cubana (Hagen), were found to be the most abundant. Alternative prey for the commercially available lacewing, Chrysoperla rufilabris Burmeister, and the native lacewing, C. cubana, were tested. Both predator species were able to complete normal development on whiteflies alone. C. cubana larvae indicated a preference for B. tabaci over the potato aphid, Macrosiphum euphorbiae (Thomas), in two different models for testing preference. C. rufilabris indicated preference for the aphid in the third instar in only one of the two preference models.; The adult stage of these two lacewing species also were tested in the laboratory for attraction to various compounds and products with an olfactometer. Of the compounds tested, an 'artificial honeydew' and L-tryptophane were found to be highly attractive to C. rufilabris, but were less attractive to C. cubana. The 'artificial honeydew' was also tested in the field for increasing the presence and oviposition of chrysopids on tomatoes and squash in the field. In general, C. cubana tended to oviposit more on tomatoes sprayed with the 'artificial honeydew' although significant effects were difficult to detect.; Although various predator species appear to be responding to the abundance of whiteflies in the field, the populations of this pest are not currently being regulated by predators. Continued studies are needed to investigate ways to manipulate predator populations such that they synchronize better with whitefly populations. The possibility of introducing exotic predators or augmenting endemic ones should be investigated.