DL-beta-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resistance against a variety of plant pathogens. However, examples of BABA-induced resistance against insect herbivores have not been reported. We applied BABA as a soil drench to legumes and monitored its effects on the pea aphid Acyrthosiphon pisum (Harris). On tic bean (Vicia faba var. minor), BABA i...

abstract competition is a phenomenon that influences the size, structure and stability of insect communities, particularly on solitary endoparasitoids species. although, competition normally incurs costs, it might be adaptive for the surviving individual. to determine which factors affect the patch use strategy of foragers under competition, the effect of previous experience with hosts already-...

Field assessments were conducted to examine the interplay between host plant and predation in complex agricultural mosaic on pea aphid clover and alfalfa races. In one experiment, we examined the relative fitness on clover race (CR) and alfalfa race (AR) pea aphids on broad bean, red clover and alfalfa alone. But because clover is typically grown in a more complex agricultural mosaic with alfal...

Beginning in 2000, snap bean (Phaseolus vulgaris L.) crops exhibiting virus-like symptoms on the foliage (leaf distortion, yellow and green mottling, and mosaic) were increasing in frequency on a regional scale across the northern United States and Canada (10,20). These crops also produced fewer pods or pods that were either twisted or necrotic (hence unmarketable). Across the Midwest and north...

The evolution of reproductive isolation without geographic isolation (sympatric speciation) has recently gained strong theoretical and empirical supports. It is now widely admitted that many host-specific phytophagous insect species have arisen through shifting and adapting to new plants. The pea aphid Acyrthosiphon pisum has received considerable attention in this context and is now considered...

Although bell bean is a true vetch, it differs greatly from other vetches with its strong upright growth. It also has a relatively shallow, thick taproot, which may be useful for opening up heavy soils. Bell bean is often used in mixes with vetches, peas, or cereals. Because of its height and because it does not tolerate close mowing, it is often omitted from mixes in frost-prone areas. Bell be...

Adviser: Brigitte Tenhumberg Food acquisition is a complicated task. The profitability of potential food items depends on numerous factors, including the spatial distribution, probability of detection and capture, and suitability of the food. Animals faced with such challenges can use relatively simple mechanisms to maximize foraging efficiency. However, mechanisms that maximize foraging effici...