Lygus hesperus Knight, the western tarnished plant bug (WTPB), is a key pest of many crops in the San Joaquin Valley (SJV) of California and causes damage by feeding on floral buds or developing seeds. In cotton, WTPB is a key pest and moves into the cotton field from bordering areas. Within an environment, crops can act as a source or sink for WTPB. A source crop produces insects and releases them during harvest or senescence. We define a crop as a sink when it can “absorb” and retain WTPB without economic consequences.
Within a landscape, an ideal sink would be a crop that is available throughout the growing season, is preferred by the insect but is not damaged by it. In the SJV, alfalfa forage fits this profile. The crop is maintained in a vigorous state of growth and not allowed to achieve a reproductive stage. Every 22-28 days the forage is removed but quickly allowed to regrow. WTPB is not a pest in alfalfa.
Our studies indicated that alfalfa is a preferred host and adults do not readily leave the field if some habitat remains available. We have demonstrated that when small strips of alfalfa are preserved during harvest, they will retain high lygus population densities.
We are using geographic information systems to evaluate township (6 x 6 miles) level landscapes for their propensity to develop WTPB problems in cotton. Our goal is to characterize the role of alfalfa in the landscape in mitigating lygus movement into cotton.
Species 1: Heteroptera Miridae Lygus hesperus (western tarnished plant bug)
Keywords: landscape ecology, areawide management
Back to Symposium: Trap Cropping--Using Insect Behavior, Plant Biology, and Landscape Management to Control Insect Pests
Back to Symposia
Back to The 2003 ESA Annual Meeting and Exhibition