Theodore M. Webster

My research interests involve studying weed-crop interactions and searching for improved weed management strategies (particularly in vegetable crops in the search for methyl bromide alternatives).

My current research is split between two primary areas of study. The first involves studying nutsedge ecology and management in vegetable crops (i.e. bell pepper, cucumber, eggplant, yellow squash, and zucchini) in an effort to find alternatives to methyl bromide. This research is focused on purple and yellow nutsedges, the primary weeds of vegetables in plasticulture systems in the southeast coastal plain. Research projects include: studying the effect of elevated temperatures on purple nutsedge and yellow nutsedge tuber viability; evaluting the influence of plastic mulch on nutsedge patch expansion over a growing season; and determining vegetable crop tolerance to halosulfuron, a herbicide and effective methyl bromide alternative for nutsedge management in some vegetable crops. Various rates of halosulfuron, application timings (e.g. before and after crop transplant/seeding), and application methods (e.g. applied to: the soil surface, through drip irrigation systems, crop and weed foliage) have been evaluated.

The second primary area of study involves studying weed-crop interactions in agronomic crops (primarily corn, cotton, and peanut). The effect of various cultural practices (e.g. crop row spacing, crop sowing density, crop growth habit/cultivar) and tillage systems (e.g. strip tillage vs. no-tillage vs. conventional tillage) are being evaluated to determine how these factors affect weed-crop interactions.

A related research project includes the validation of a weed management decision support system (developed at North Carolina State University) for Georgia cotton. This system, HADSS for Georgia cotton, provides users with the means to evaluate weed control options using weed biology, herbicide efficacy on weeds, and economics. The model has been reseased and is available over the internet.

Previous research topics have included weed-crop interference, spatial and temporal emergence and expansion patterns of weed patches, and the evaluation of the accuracy and precision of a global positioning system (GPS) used to monitor changes in weed populations over time. I have worked in several different agronomic crops (corn, soybean, wheat, cotton, peanut) with a concentrated effort on many different weed species (Florida beggerweed [Desmodium tortuosum], giant ragweed [Ambrosia trifida], purple nutsedge [Cyperus rotundus], sicklepod [Senna obtusifolia], and hemp dogbane [Apocynum cannabinum]). Results from the aforementioned weed-crop interference studies have been used in the creation of computer weed management decision aids in soybean in Ohio (giant ragweed) and corn and cotton in North Carolina and Georgia (purple nutsedge).