Managing Weeds with Reduced Herbicide Inputs: Developing a Novel System for Onion

Weeds are a major challenge in crop production. Often weeds cause significant yield losses and even a few weeds producing seeds can cause weed problems in subsequent years. For example, sicklepod (Senna obtusifolia) average seed production is 8,000 seeds per plant (English and Oliver, 1981). Chemical weed control methods have been shown to be one of the most cost effective weed control options (Pike et al., 1991). Herbicides dominated the pesticides used in the United States during 2004 and accounted for two-thirds of the approximately $8.5 billion spent on agricultural pesticides (Padgitt et al., 2000). However, with the weed control benefits from herbicide usage also came environmental and health concerns. These concerns have resulted in much research on the safety of each chemical. Most of these environmental and health concerns are dealt with prior to herbicide registration. Manufacturers conduct numerous experiments in order to accurately determine product utility, market value, and regulatory needs. These experiments include toxicity trials to a wide range of organisms to determine the product’s safety to plants, animals, and environmental fate. In addition, an enormous amount of testing is done for product quality and efficacy. Considering the vast investment that a manufacturer has incurred prior to product launch and the relatively short period of time to recoup their investment before the product is off patent, it becomes crucial that a product is registered quickly and at the lowest effective use rate. Recommending rates above this rate would potentially lead to widespread rate reductions, while recommending rates below this rate would potentially lead to widespread performance issues. With either scenario, the manufacturer’s ability to recoup their investment becomes greatly reduced.