For 2020 and newer grants, please go to https://grants.ipmcenters.org/
Home       Current RFAs       PD User Guide       Projects       Login

Funded Project

Funding Program: Regional IPM Competitive Grants - Northeastern

Project Title: Double Ringed Trap Crop System: Completely Pesticide-Free IPM Program for Peppers

Project Directors (PDs): T. Jude Boucher [1] Richard Ashley [2]

Lead State: CT Lead Organization: University of Connecticut

Extension Funding: $23,443

Research Funding: $64,973

Start Date: Jun-15-2000 End Date: Jun-14-2003

Pests Involved: European corn borer, pepper maggots, aphids

Site/Commodity: peppers

Area of Emphasis: trap crops

Summary: Description of the problem: Our food-based IPM systems are stuck in a phase where we are reliant on pesticides as the ultimate solution. The academic institutions and chemical industry have improved cooperative efforts in recent years to help produce more environmentally sound pesticides (especially microbial products), but we seem to be mired in the idea that the magic bullet can be purchased in a bottle, while farm profitability continues to decline. The problems identified by our stakeholders (National IPM Initiative Phase I Project - IPM for Diversified Fresh Market Vegetable Producers in NY, NJ and PA) concerning pepper production epitomize the extent of the problem. Aphids, a completely induced secondary pest problem on peppers (Foster and Flood 1995), are listed as the most frequent insect pests (52% of respondents identified aphids as a key pest). Many other secondary pests were identified as serious problems in pepper production, including leafminers, mites, thrips, and whiteflies. The greatest primary pest on peppers, European corn borer, was rated a distant second, while other primary pests (pepper maggot, corn earworm, fall armyworm, etc.) problems were barely acknowledged (possibly because they are masked by heavy pesticide use and the persistence of preventative cover sprays). As IPM decision-makers we have to ask ourselves, have we accomplished our goals if we only succeed in swapping one set of pests for another? The secondary pests mentioned above reproduce quicker, tend to develop resistance faster and are less likely to be controlled with pesticides. A review of client-identified problems on peppers in the recently created NAPIAP web site confirms that secondary pest status increases, with pesticides use and pest pressure, as we move from north to south. Opportunity for IPM: New trap crop strategies have proven themselves highly effective on tough pests in other cropping systems in recent years, when implemented by completely encircling the main crop. Preliminary tests on the pepper maggot indicate that proper placement of a highly attractive host may succeed in controlling pests which must enter the crop arena from the periphery (such as the PM and ECB). Trap cropping for multiple pepper pests, combined with cultural/mechanical controls and resistant varieties, offers the potential to create the first zero-pesticide IPM system that maintains or increases crop quality compared with conventional production methods. Even if we fail to control all pests as proposed, we should still substantially reduce pesticide use with a cheaper, simpler, user-friendly system that eliminates many off-farm inputs and expenses. Also, this technology should be easily transferable to other crops/pests and regions. Project objectives: To simultaneously control all direct and secondary pepper pests through a combination of alternative strategies, including multiple trap crops, resistant plants, and cultural/mechanical controls. To demonstrate and implement this second-level IPM system on commercial farms as we conduct the research. To produce a paradigm shift from a bottled solution to an altered crop system approach. (See section D for more details on objectives). Description of methods (effort): Research on the combined trap crop system will be conducted on a commercial farm with a history of the insect problems mentioned. In one field the trap crops (only) will be sprayed (the conservative approach) while in another field, a completely pesticide-free system will be tested. A second farm (2,000 acres of total crops, 800 acres vegetables, up to 39 acres peppers), run by one of the most successful and respected producers in the state, will attempt to implement the combined system for his entire pepper crop immediately, as part of our Extension effort to accelerate adoption of the new approach. Description of the problem, background and justification: Current practices: Current pesticide use on peppers is quite high. Some conventional pepper producers in the northeast use more than 14.6 pounds of active ingredient per acre to combat pests on this crop (excluding fumigants - up to 200 lbs. AI/acre). Total pesticide use in the Northeast region on over 9,000 acres of peppers is estimated to exceed 184,000 pounds of active ingredient. Many of the most commonly used pesticides (e.g. methomyl, endosulfan, diazinon, metalaxyl, metam-sodium, methyl bromide, acephate, dimethoate, imadicloprid, maneb, and permethrin) have high or moderate leaching potentials, may be present in trace amounts at harvest (long residual periods), are highly toxic, expensive and hard on natural enemies. Key pepper pests in the Northeast include weeds, bacterial leaf spot, phytophthora blight, European corn borer (ECB), green peach aphid, pepper maggot, and occasionally in the mid-Atlantic states, corn earworm, fall, and beet armyworm. In a best-case scenario, most of these pests can be managed with a combination of cultural and biological controls. Cultivation and plastic mulch are used for weeds; hot-water seed treatment, resistant varieties, crop rotation, proper site selection and water management help prevent the two major diseases; monitoring, thresholds and selective insecticides (spinosad, tebufenozide, and Bacillus thuringiensis) are effective for the corn borer and other caterpillars; and natural enemies control aphids (Foster and Flood 1995) and most secondary pests on peppers in the absence of broad-spectrum pesticides. Inadequacies of current technologies and practices: In recent years, IPM programs have been criticized for an over-reliance on pesticides. Farm profitability continues to decline because crop prices remain low while production costs continue to rise. Some of the new selective or microbial pesticide "solutions" sell for over $500 per gallon (i.e. spinosad) or cost more than $70 per application (i.e. imadicloprid). Conventional/IPM growers report induced secondary pests as common problems on peppers, while complaining they haven't enough time to adequately scout for and monitor pests. Growers continue to incur additional costs for sprays aimed at secondary pests. Extension specialists and agents increasingly have assignments across all vegetable crops, or all green-industry and horticultural crops, leaving little time to develop the depth of knowledge necessary to implement complicated and detail-oriented IPM programs. We need a simpler but more complete solution to the pest complex problem. In addition, all too often growers are reluctant to switch to new selective pesticides which they consider to be more costly, too specific and less effective than older broad-spectrum pesticides. A continued reliance on preventative broad-spectrum cover sprays creates many of the secondary pest problems that are so common in the mid-Atlantic states and further south. However, when calendar-based, broad-spectrum insecticide applications are actually removed from the production system, the pepper maggot (PM) becomes a significant problem on over half the pepper farms in New England (and exists in all states along the East coast). This pest has infested up to 90% of the crop in unprotected pepper fields. Because its potential damage is often masked by calendar-based spray programs, the PM has often been considered a minor pest, and no alternative control measures have been developed. PM damage is likely to increase as IPM programs recommend the use of selective growth regulators or microbial insecticides for corn borer control. Multiple applications of broad-spectrum and systemic materials are currently the only controls available for the maggot. Northeast region identified stakeholder needs: The National IPM Initiative Phase I Project, 'IPM for Diversified Fresh Market Vegetable Producers in NY, NJ and PA', survey identified peppers as the fourth most commonly produced vegetable crop in the three states (raised by 43%) and first in NJ (raised by 54%). Survey respondents identified the following important issues in discussions: declining prices, regulations, spraying costs, the many different sprays [pesticides] required for crops, and fear of public condemnation due to spraying. However, these growers identified aphids, an induced secondary pest on peppers (Foster and Flood 1995), as the most frequent insect pests (52% of respondents identified aphids as a key pest while ECB, the main primary pest, was rated a distant second at 39%). Many other secondary pests were identified as problems, while other primary pests were barely acknowledged. When growers in New England were asked "what pest problems should IPM concentrate on in peppers", 64%, 61%, 55% and less than 33% indicated insects, diseases, weeds, and all other categories, respectively (MA Pepper Survey 1996). When asked "what insects were responsible for crop damage" 83%, 28%, 11% and 11% responded ECB, PM, aphids and other, respectively. The Northeast IPM Needs Database identified better management options and environmentally-friendly alternatives for ECB and PM as stakeholder priorities for peppers. Proposed improvements in IPM system: A relatively new trap crop strategy, together with other second-level (alternative control based) IPM techniques, offers the potential to minimize or eliminate the use of pesticides on peppers and preserve natural enemies that control aphids, while simultaneously maintaining or increasing crop quality and yield. However, to increase IPM implementation, adoption, and farm profitability, we must simplify the system. Literature review: Trap crop techniques have been improved in recent years, resulting in a dramatic improvement in efficacy against insects that must enter the crop arena from the outside. The idea is simple: intercept and/or kill the insect by completely encircling the crop with something that is more attractive to the pest (Aluja and Liedo 1986). This concept has been successfully tested by many different researchers in recent years using baited traps (Prokopy et al. l990, Duan and Prokopy 1995), and trap crops (Aluja et al 1997b, Derridj et al. 1988, Hunt and Whitfield 1996, Mitchell et al. in press, Srinivasan and Krishna Moorthy 1991, Boucher unpublished data). In addition, economic analysis on trap cropping always shows that it result in higher net profits for growers (Hokkanen, 1991). Studies have shown that the diamondback moth (DBM) is more attracted to collards than other crucifers (Harcourt 1957, Mitchell et al. 1997). Mitchell et al. (in press) encircled nine 5 to 12 ha cabbage fields with two rows of collards as a trap crop barrier and found that DBM larvae (alone) never exceeded the action threshold in the cabbage, although they did in the trap crop (89% of the time) and in nearby control fields (60%). Trap crops reduced insecticide sprays 56% (there were sprays for other insects) for a net savings of $117-156 per ha in pesticide costs alone. Mitchell (Boucher and Mitchell, in press) also found that when local growers unintentionally left breaks in the trap crop barrier surrounding the cabbage, the gaps acted "like gates had been left open and the diamondback moth moved further into the field [beyond the trap crop] from these areas causing extensive damage to the cabbage." Srinivasan and Krishna Moorthy (1991) successfully protected cabbage from DBM in India by encircling fields with Indian mustard. Hunt and Whitfield (1996) planted tomato plots with or without a single row of potatoes in exterior rows for Colorado potato beetle control. The trap crop effectively concentrated the beetle population in the potato row and increased crop yield on the unsprayed tomato plots 61 - 87% compared to control plots without the trap crop. Aluja et al. (1997a) showed how papaya fruit flies take refuge in the canopy of native vegetation along orchard margins and found oviposition and fruit damage to be highly aggregated on plants in closest proximity to shelter sites. When a single row of a highly attractive papaya variety was planted around the perimeter of an experimental papaya orchard, trees in the main crop had 86% fewer damaged fruit (97% clean fruit) than those in the trap crop margin (Aluja et al. 1997b). Prokopy et al. (1990) and Duan and Prokopy (1995) successfully protected apples from apple maggot attack by hanging highly attractive visual/baited traps in the outer row of trees around the periphery of the orchard. Many Extension workers have observed how, on occasion, an unsprayed pepper field in close proximity to a sweet corn planting does not become infested with ECB despite extensive damage to the corn (Walker and Hazzard personal communication, Boucher unpublished data). Derridj et al (1988) encircled commercial corn fields with highly attractive (susceptible varieties) trap plant strips of maize, and compared them with solid stands of less susceptible corn (= commercial variety). They succeeded in concentrating ECB oviposition on the trap crop barrier plants: twice as many egg masses were found in the strip than in the main crop. They concluded that to limit egg mass density it is necessary to grow the trap crop all the way around the maize field. They also made suggestions for improving the degree of efficacy by increasing the width of the trap crop border where necessary, using different growth stages or more attractive varieties of maize, and by growing other (a mix of) susceptible crop species. Udayagiri and Mason (1995) explored plant constituents as ECB oviposition stimulants and found that borers preferred corn over pepper when offered a choice between foliar extracts. Preliminary experimental results: Boucher et al. (submitted) showed that native tree canopies serve as shelter sites for PM flies when they are not in the crop. The pest was reliably monitored with baited sticky traps in nearby maples trees, but the same traps did not work in pepper fields. In 1998 and 1999, unsprayed bell pepper fields (0.7-1.3 acres) were used to document the spatial distribution of maggot oviposition relative to native vegetation (nearest treeline). Infestation declined with increasing distance from the treeline and was dramatically lower more than 30 meters from the trees (Boucher et al. unpublished data). This insect also has a strong preference for hot cherry pepper fruit over bells (Hazzard et al. 1997). In 1999, two 0.7 acre pepper fields were planted on a single commercial farm: one with four rows of hot cherry peppers on three sides of the main crop (bells) and a wider barrier of 20 trap plants closest to the woodline, the second a solid stand of bell peppers. The hot cherry pepper trap crop was left untreated for the first two weeks of oviposition and then sprayed with acephate two and four weeks later, while bell pepper plants in each field were left unsprayed. Fruit from plants were sampled in a grid pattern across both fields and examined for stings and maggot infestation as larvae matured. When just the bells in the trap crop field were compared to the same inner positions (only) in the all-bell field (at positions away from the edge at 30, 457 60, 75 meters from the trees), there was an 81 % reduction in maggot infestation in the bell peppers surrounded by hot cherries. When just the bells in the trap crop field were compared with all the sample sites in the all-bell field, there was a 96% reduction in PM infestation using the barrier. In both fields, stings and maggot infestation in bell fruits declined as distance from the treeline increased. In cherry peppers, stings and maggot infestation declined in the first 30 meters from the treeline, but then stayed relatively constant to the far end of the field. The fact that flies were willing to follow the 4 rows of cherry peppers out along the edge of the field for 90 meters, while causing little to no damage to adjacent bells at the same distances, demonstrates just how attractive the trap crop was to the fly. Trap cropping as an alternative control for pepper maggot holds tremendous potential based on these preliminary results. The authors believe the same may be true for ECB and other pests that enter the crop arena from the outside. Objectives: Research objectives 1) Control European corn borer oviposition/damage in bell peppers by completely encircling fields with rows of a sweet corn variety (or rows of sweet corn/potato) that is both highly-preferred by this pest and in the correct stage of development to maximize attractiveness. Intercept adult ECB moth flight between action sites outside of the crop and the peppers by adjusting the sprayed/unsprayed trap crop border width, development stage or species as needed. 2) Control pepper maggot oviposition/damage in bell peppers by completely encircling fields with rows of highly-preferred hot cherry pepper plants. Intercept adult pepper maggot flies during their daily migration from tree canopies (native vegetation) into pepper fields by adjusting the sprayed/unsprayed trap crop border width (or variety) as needed (especially along treelines). 3) Show that trap cropping is simpler and less expensive than using chemicals through a cost/benefit analysis. Extension objectives 4) Combine all trap crop, resistant variety, cultural and mechanical controls in large commercial fields of IPM program participants to document effects and encourage the proliferation of the system to other farms and states (with the help of journal articles, Extension literature, demonstrations and talks). 5) Eliminate aphids as a major grower concern on peppers, by leaving at least the main crop of bell peppers unsprayed and preserving natural enemies which will control this pest and other secondary pests, with few exceptions.

Close Window

Northeastern IPM Center 340 Tower Road Cornell University Ithaca, NY 14853 NortheastIPM.org		Developed by the Center for IPM © Copyright CIPM 2004-2026