Bemisia tabaci on Vegetables in the Southern United States: Incidence, Impact, and Management.

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is among the most economically important insect pests of various vegetable crops in the Southern United States. This insect is considered a complex of at least 40 morphologically indistinguishable cryptic species. Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) was initially introduced in the United States around 1985 and has since rapidly spread across the Southern United States to Texas, Arizona, and California, where extreme field outbreaks have occurred on vegetable and other crops. This pest creates extensive plant damage through direct feeding on vegetables, secreting honeydew, causing plant physiological disorders, and vectoring plant viruses. The direct and indirect plant damage in vegetable crops has resulted in enormous economic losses in the Southern United States, especially in Florida, Georgia, and Texas. Effective management of B. tabaci on vegetables relies mainly on the utilization of chemical insecticides, particularly neonicotinoids. However, B. tabaci has developed considerable resistance to most insecticides. Therefore, alternative integrated pest management (IPM) strategies are required, such as cultural control by manipulation of production practices, resistant vegetable varieties, and biological control using a suite of natural enemies for the management of the pest.

Comparative Assessment of Four Steinernematidae and Three Heterorhabditidae Species for Infectivity of Larval Diabrotica Virgifera Virgifera.

Larval Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) were exposed to seven different entomopathogenic nematode species to test their potential infectivity in a laboratory setting. Known D. virgifera-infecting nematode species Heterorhabditis bacteriophora Poinar, Heterorhabditis megidis Poinar, Jackson & Klein, Steinernema feltiae Filipjev, and Steinernema carpocapsae Weiser were tested in a concerted experiment alongside Steinernema diaprepesi Nguyen & Duncan, Steinernema riobrave Cabanillas, Poinar & Raulston, and a Missouri wild-type H. bacteriophora which have not been previously tested on D. virgifera. The species S. rarum Doucet was tested separately for D. virgifera infectivity. Third-instar D. virgifera were exposed to either 60 or 120 nematodes per larva for 6 d. Following exposure, mortality was recorded and larvae were examined to determine the presence of active nematode infections. Results indicated a significantly higher proportion of larvae with active infections from the Heterorhabditidae species and S. diaprepesi than the other Steinernematidae species for both exposure rates; mortality data indicated a similar trend. Steinernema rarum showed almost no infectivity in laboratory experiments.