EVALUATING THE EPAS COMPARATIVE PRODUCT PERFORMANCE TESTING GUIDELINES FOR HERBICIDES IN SNAP BEAN (PHASEOLUS-VULGARIS)

Following suggested guidelines developed by the Environmental Protecti on Agency (EPA), comparative snap bean herbicide performance field tri als were conducted from 1993 to 1995 in New York. Data were obtained o n crop injury, weed control, and weed biomass, and crop yield, quality , and losses during harvest. Trifluralin, EPTC, and pendimethalin appl ied preplant incorporated (PPI) and applications of metolachlor applie d preemergence (PRE) provided less than adequate control of redroot pi gweed, common lambsquarters, and hairy galinsoga. Cultivation improved weed control with PPI and PRE applications. Metolachlor + fomesafen P RE provided good control of hairy galinsoga, adequate redroot pigweed control, and marginal control of common lambsquarters. Fomesafen appli ed postemergence (POST), combinations of metolachlor applied PRE with fomesafen or bentazon applied POST, and fomesafen + bentazon applied P OST adequately controlled the three weed species without cultivation. Herbicide treatments had little measurable impact on snap bean quality or losses during harvest. Information from product comparison trials maybe useful in developing recommendations for growers but may prove, less than adequate in providing data necessary for a thorough evaluati on of the relative benefits of individual herbicides as intended by EP A guidelines. Difficulties were encountered in following the guideline s, and costs of conducting the product comparison trials for a single crop in one growing region exceeded $90,000 over 3 yr.