Intraguild predation (IGP) is pervasive in many managed and unmanaged ecosystems and may have negative, neutral or positive effects on the biological control of pest insects. Both generalist predators and aphelinid parasitoids attack Bemisia tabac i (Gennadius) Biotype B ( B. argentifolii Perring & Bellows) on cotton in the southwestern USA. Free-choice and no-choice laboratory assays were cond...

The role of induced responses of tomato, Lycopersicon esculentum, in interspecific interactions between two polyphagous herbivores, the silverleaf whitefly, Bemisia argentifolii (WF), and the vegetable leafminer, Liriomyza trifolii (LM), was characterized in laboratory and field experiments. Feeding by LMs and WFs induced local and systemic production of putative defensive proteins, i.e., chiti...

We conducted a controlled experiment to test the plant vigor and the plant stress hypotheses. The two hypotheses associate plant physiological conditions to insect feeding mode and performance. We exposed tomato, Lycopersicon esculentum, to different types of growing conditions: optimal (vigorous plants), resource based stress (water and/or nutrient deficit), and physical stress (punched hole i...

A Ðeld-collected population of the silverleaf whiteÑy, Bemisia argentifolii, was selected with the nicotinyl compound, imidacloprid, over 32 generations to determine if resistance would develop when maintained under continuous selection pressure in a greenhouse. Resistance was slow to increase at Ðrst with low to moderate levels of resistance (RR from 6to 17-fold) in the Ðrst 15 generations of ...

Behaviors of Eretmocerus sp. nr. californicus females attacking Bemisia argentifolii Bellows & Perring infesting cotton, Gossypium hirsutum L., and melon, Cucumis melo L., were quantified. Adult female behaviors were described and quantified for Eret. sp. nr. californicus to establish a behavioral time budget analysis. Females readily searched for host whitefly nymphs on cotton leaves with walk...

Some elicitors of plant defensive systems can induce biochemical changes that enable the plant to reduce disease incidence; however, little is known about the effect of these induced responses on insect herbivores. We approached this problem using exogenous field applications of several abiotic elicitors of defensive systems in tomatoes (Lycopersicon esculentum), and evaluated the ability of th...