Herbicide tolerance and weed control strategies for Lesquerella production

Abstract

Lesquerella fendleri (Gray) Wats, has the potential of being an economical, water-efficient source of hydroxy fatty acid that is useful in the production of specialty lubricants, plastics, coatings, and cosmetics. Lesquerella's slow initial growth habit makes it noncompetitive with most weed species. This is especially true during the spring when the more aggressive summer weeds begin to appear. Because the cost of hand-weeding is commercially prohibitive, the primary subject of this study was to develop effective weed control strategies for Lesquerella, including herbicide tolerance, efficacy, and application techniques. Three years of herbicide tolerance studies in the field and greenhouse have identified preplant incorporated (PPI), postemergence (POST), and layby (LAY) herbicides to which Lesquerella is tolerant (less than 15% damage, with 100% damage meaning complete kill). Because Lesquerella is a new crop, which also could be a potential weed, it was also necessary to note several herbicides to which it has no tolerance. Herbicides that appear to be excellent candidates for registration include, PPI: trifluralin, benefin, and ethalfluralin; POST: oxyfluorfen, fluazifop, clopyralid, and sethoxydim; LAY: pendimethalin and DCPA. Rates and timing of application are very important for some materials. Materials that are potential, but less likely, herbicide candidates include, PPI: pendimethalin; PRE: napropamide and pronamide; POST: pronamide and dicamba.