An Extension Perspective of the Minor Use Crops Pesticide Problem in Vegetable Production

In October 1988, Congress amended the Federal Insecticide, Fungicide and Rodenticide Act (called FIFRA 88) and mandated that all pesticide uses registered prior to 1984 be re-registered by late 1997 to meet current human health and environmental standards. This legislation has serious implications for the so-called "minor use crops," which include vegetables, fruits, nuts, and ornamentals. With respect to pesticides, minor use crops are those that consist of very limited acreage, or produce relatively little revenue for the manufacturer ("registrants") of pesticides used on those crops.

Cost is a major consideration in whether or not to pursue registration of a pesticide. Minor use crops, such as vegetables, are of major significance in agricultural production for many growers, as well as for consumers throughout the United States. In some cases, an entire agricultural production area consists of minor use crops, and these areas would be most negatively impacted by the 1988 FIFRA amendment. New Jersey, for example, contains areas which produce only vegetable crops (Table 1), of which all are considered minor use crops with respect to pesticides. Overall, minor use crops are valued at $327 million in New Jersey, and account for 88% of the value of all crops grown in the state (U.S. Census of Agriculture, 1987).

Re-registration of pesticides will require additional research and testing by the manufacturers, costing millions of dollars. Minor use crops account for about one-half of the nation's $70 billion worth of agricultural sales, but the pesticides used on these crops are only a small percentage of total pesticide sales. Pesticide manufacturers seek the major crop registrations (cotton, soybeans, corn) in which the returns justify the investment in time and money. They do not find it economically feasible to spend the time or money necessary to re-register existing minor use crop pesticides, let alone to develop and register new pesticides for these crops. Economic reasons, as well as environmental concerns, have resulted in the cancellation of over two dozen federal pesticide registrations (labels) since 1980 that were important to pest management in minor use crops (Table 2).

To obtain a more complete picture of how Extension agents view the current and future situation with minor use crop pesticides, 18 agricultural agents with Extension responsibilities related to vegetable crops were surveyed. These agents were located throughout the eastern U.S. coastal states and included nine Extension specialists, seven county agricultural agents, and two research/Extension personnel. A total of 16 agents (89%) responded to this survey.

The survey included questions about factors that could affect minor use crop pesticide labels, including re-registration, IR-4, and Integrated Pest Management (IPM), and how these relate to their Extension programs to assist growers in pest management for vegetable production.

When asked whether or not label losses due to re-registration would significantly impact vegetable production in their region, most agreed that FIFRA 88 would likely make pest control more difficult. Seventy-two percent said yes, 11% maybe, 6% said yes in certain years, and 11% said no impact will occur. However, it is important to point out that, because additional pesticide labels will probably be canceled due to re-registration, these responses will likely change in the near future. Pesticides such as methamidiphos, mevinphos, naled, oxydemeton-methyl, and others may be canceled in the next few years due to the high cost of re-registration.

The insect pests of most concern when considering the lost or soon-to-be lost pesticide labels are listed in Table 3. These insect pests are difficult to control and include many sap-sucking insects such as aphids, thrips, whiteflies, and mites. Previously, these insect pests were controlled using certain broad-spectrum insecticides, and as these materials have been and will be lost, the availability of different chemical classes of insecticides decreases, which will make it even more difficult to control these pests.

Most respondents also stated that soil insect pest control will be significantly impacted. Pests such as wireworms and grubs have traditionally been difficult to control even with the use of insecticides. Without insecticides, economic control will be impossible since there currently are no alternatives.

All but two respondents felt that the loss of broad-spectrum pesticides will lead to increased pesticide resistance. The over-use of pyrethroids was mentioned most often as an example of increased pesticide resistance due to losses of pesticide registrations. Pyrethroids are already ineffective against several important pests, including the Colorado potato beetle and diamondback moth larva, throughout the eastern U.S. (Forgash, 1981). Most agricultural agents reported that pyrethroids favor aphid outbreaks by killing the natural enemies without affecting the pyrethroid-resistant pests.

Several respondents believe resistance to Bacillus thuringiensis (Bt) will increase if growers are forced to abandon the broad spectrum insecticides and overuse pyrethroids and Bt's. Resistance to Bt has already been documented for the Colorado potato beetle, diamondback moth, and gypsy moth (Rossiter, Yendol, & Dubois, 1990; and Tabashnik, Cusahing, Finson, and Johnson, 1990). Additionally, one respondent stated that a reduction in available pest control chemicals will result in higher post-harvest losses.

The loss of broad-spectrum insecticides will likely lead to an increase in insect-transmitted plant diseases. Seventy-five percent of those surveyed said plant diseases would increase, 19% felt they might increase, and 6% said no increase would occur. Most of the diseases of concern were those that are transmitted by aphids, leafhoppers, or thrips, which were the insect pests described as most likely to occur as serious pests in the near future due to cancellation of effective insecticides.

Only 69% of those responding were active participants in the IR-4 program, although all but one felt that the IR-4 program was helpful in retaining or obtaining minor crop labels. The primary reason for non-participation was the lack of professional recognition obtained from the University. Most respondents felt that their participation in the IR-4 program will decline in the future due to overly strict record keeping and the excessive amount of paper work required for each project. Other reasons included "not enough time" or "not enough funding." Reduced federal and state funding has resulted in fewer Extension agents, area specialists, and support staff (Thompson, 1991). Traditionally, these are the most active IR-4 program participants within the University system. Because of the reduction in available funds and personnel, Extension agents must provide more educational meetings and newsletter information to make growers aware of the re-registration process, and enlist their direct involvement in grower groups working with pesticide registrants under EPA's guidance. Growers must use all available information and participate as much as possible, and they will not be able to rely solely on Extension (Aylsworth, 1983).

All of the respondents agreed that integrated pest management is important and is the key to the production of vegetables in the future. Although biological and cultural controls will likely become commonplace, more than 60% of the respondents stated, in almost exactly the same words, that "pesticides will likely always be needed for pest management in minor use crops." Pesticides should be used judiciously in a pest management program utilizing all effective methods of pest control.

In summary, pesticide registration cancellations have, and will continue to have, a negative impact on U.S. vegetable production. In states like New Jersey, where minor use crops account for more than 88% of agricultural production, this would be disastrous. Vegetable growers can expect increased insect, disease, and weed pest problems because effective alternative measures are simply not available. Effective and economic alternatives to pesticides must be available for growers to implement before the minor crop pesticide registrations are canceled.

Extension personnel should help growers contact their state, regional or national IR-4 program to become involved in pesticide registration and re-registration. Training sessions should be arranged to assist growers in these efforts. Growers could be made aware of, and encouraged to join, other grower organizations or groups that have similar pest control needs to develop strategies, share information, and express their needs at all levels of administration. These grower groups could also be encouraged to fund certain studies which support a specific pesticide use or product. Educational meetings and grower newsletters will help disseminate information on the successes of these activities.

What research can do, and what society demands, do not necessarily match. Current research lags behind the needs of production agriculture, and there are no alternatives available to targeted pesticides. The option of using different classes of insecticides is still one of the most important tools we have for resistance management. Growers need to maximize the use of all available pest management tools, including the pesticides we now have, to better manage the pest populations.

Education is the most important factor in the safe and environmentally responsible use of agricultural pesticides. The education of growers and farm workers concerning proper pesticide use must be continuous. The public also needs accurate information on important issues facing modern vegetable production, such as food safety, the pesticide registration process, risk/benefit assessment, integrated pest management, and environmental impacts. Knowledge of these issues will help the public better understand the risks and benefits of pesticide use necessary to maintain our high quality, high quantity vegetable production.

A version of this report is available as New Jersey Agricultural Experiment Station publication No. D-08130-08-93. This research was supported by State funds and by the United States Hatch Act.

Aylsworth, J. D. (1993). A new look for extension. American Vegetable Grower, 41, 14-17.

Forgash, A. J. (1981). Insecticide resistance of the Colorado potato beetle. Advances in Potato Pest Management. Stroudsburg, PA: Hutchinson Ross.

Rossiter, M., Yendol, W. G., Dubois, N. R. (1990). Resistance to Bacillus thuringiensis in gypsy moth: Genetic and environmental causes. Journal of Economic Entomology, 83, 2211-2218.

Tabashnik, B. E., Cusahing, N. L., Finson, N., Johnson, M. W. (1990). Field development of resistance to Bacillus thuringiensis in diamondback moth. Journal of Economic Entomology, 83, 1671-1676.

Thompson, T. (1991). IR-4 needs grower and financial input to succeed. The Grower, 24, 32-33.

U.S. Census of Agriculture (1987). (AS87-AZ-51). Washington, DC: U.S. Department of Agriculture.