The efficacies of bentazon and fomesafen in controlling annual weeds in dry and edible pod beans in New York State were investigated in greenhouse and field experiments. Dose responses to bentazon and fomesafen were studied for four weed species (ragweed, velvetleaf, eastern black nightshade, and hairy nightshade) under greenhouse conditions. Herbicides were applied at cotyledon to two-, two- to four-, and four- to six–true leaf stages, both with and without a crop oil concentrate (bentazon) or a nonionic surfactant (fomesafen). Field studies were conducted for 2 yr for all weed species except eastern black nightshade, for which no adequate field populations were found. Field studies confirmed greenhouse results, indicating that weed control could be improved by the use of an adjuvant, but there were exceptions. In general, adjuvant usage improved the efficacy of fomesafen more than it did with bentazon. The minimum rates of herbicide required for effective and consistent control was dependent on the particular combination of weed species, herbicide and its rate of application, growth stage at which the application was made, and adjuvant usage.

The Interregional Research Project Number 4 (IR-4) Specialty Food Crops Program is a publicly-funded program initiated in 1963 to develop and submit regulatory data to support registration of pest control products for specialty crops. In the early to mid 1990s, nearly 45% of the IR-4 residue projects supported new herbicide registrations for fruits and vegetables with the other 55% devoted to fungicides, insecticides, and nematacides. In 2005, the number of residue projects conducted by IR-4 to support herbicide fruit and vegetable registrations was less than 30%. The three main factors that have contributed to this decline are: fewer herbicides available for registration; product liability concerns; and an increased focus on new, safer, and Reduced Risk Pesticides for insect and disease control. It has been a number of years since a new herbicide has been developed for a major crop that could be extended to specialty food crops. Many of the current IR-4 herbicide projects are with products that have been on the market for 20 or more years. Product liability is a concern because of the high value of many specialty crops relative to the potential market opportunity. In many cases, the registrant requires product performance data before IR-4 can proceed with a residue project. With limited funds for developing these data, many new projects never proceed to the regulatory stage. Although registrants can seek indemnification for some of these uses, it is a complicated often state-specific process. IR-4 has been successful in a number of areas, including the registration of a large numbers of uses through reduced data extrapolations for products such as glyphosate and carfentrazone-ethyl. Additionally, IR-4 submitted the first successful petition establishing an exemption of tolerance for a conventional herbicide (imazamox). Future IR-4 initiatives include collaboration with industry, growers, and academia to develop new herbicide technologies such as plant breeding or transgenic crops and generation of appropriate data to extend those products to specialty food crops. IR-4 will also assist in registering products that can be used on crops that have been selected (or developed through biotechnological approaches) to be tolerant to existing herbicides. Registrants should strongly consider developing herbicides for specialty food crops, with IR-4's assistance, as a means to expand markets and also as a means to extend data protection of their products, as allowed under the Food Quality Protection Act.

Greenhouse and field studies were conducted in 1991 and 1992 to determine the potential for interaction among pyridate (0.5, 1.0 kg ai/ha), sethoxydim (0.22 kg ai/ha), and crop oil concentrate (COC) (1.25% v/v) applied alone or in two- and three-way combinations to transplanted cabbage. Additionally, the effect of applying sethoxydim and COC 1 and 2 d before and after application of pyridate was investigated. In greenhouse-grown cabbage, injury increased twofold and dry weight was reduced 15% when pyridate dose was doubled. Sethoxydim increased pyridate injury significantly, reducing dry weight 31%. When COC was applied with pyridate, injury increased and dry weight decreased linearly. Despite substantial crop injury 7 d after treatment with pyridate alone, pyridate + sethoxydim, and pyridate + COC, yields of field-grown cabbage were reduced significantly in 1 yr only when the three materials were combined. Pyridate injury decreased as time between sethoxydim + COC applications, before and after pyridate was applied, increased.

Following suggested guidelines developed by the Environmental Protection Agency (EPA), comparative snap bean herbicide performance field trials were conducted from 1993 to 1995 in New York. Data were obtained on crop injury, weed control, and weed biomass, and crop yield, quality, and losses during harvest. Trifluralin, EPTC, and pendimethalin applied preplant incorporated (PPI) and applications of metolachlor applied preemergence (PRE) provided less than adequate control of redroot pigweed, common lambsquarters, and hairy galinsoga. Cultivation improved weed control with PPI and PRE applications. Metolachlor + fomesafen PRE provided good control of hairy galinsoga, adequate redroot pigweed control, and marginal control of common lambsquarters. Fomesafen applied postemergence (POST), combinations of metolachlor applied PRE with fomesafen or bentazon applied POST, and fomesafen + bentazon applied POST 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 may be useful in developing recommendations for growers but may prove less than adequate in providing data necessary for a thorough evaluation of the relative benefits of individual herbicides as intended by EPA guidelines. Difficulties were encountered in following the guidelines, and costs of conducting the product comparison trials for a single crop in one growing region exceeded $90,000 over 3 yr.

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