Perimeter trap crop approach to pest management on vegetable farms

Final Report for LNE03-177

Project Type: Research and Education
Funds awarded in 2003: $139,527.00
Projected End Date: 12/31/2005
Matching Non-Federal Funds: $108,434.00
Region: Northeast
State: Connecticut
Project Leader:
Ruth Hazzarad
University of Massachusetts
Co-Leaders:
Jude Boucher
UNiversity of Connecticut Cooperative Extension
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Project Information

Summary:

Perimeter trap cropping (PTC) involves planting a more attractive host plant so that it completely encircles and protects the main cash crop like fortress walls. The preferred host or trap crop then serves to intercept pest migration and concentrate the population in the border area, where they can be retained or controlled with perimeter sprays. We set out to design and test PTC systems for 2 to 4 commodities in replicated research trials at university and commercial farms and to help popularize the use of these systems. Growers suggested the PTC systems to study and tested these and additional systems in commercial fields. Thirteen replicated experiments were conducted. Information about PTC was spread through a series of conference talks, farm tours, poster displays and publications.

Introduction:

Perimeter trap cropping (PTC) involves planting a more attractive trap crop so that it completely encircles and protects the main cash crop like fortress walls. Efficacy can often be improved by supplementing the system with other perimeter defenses (i.e. perimeter sprays). In 2003, we set out to design and test PTC systems for 2 to 4 commodities in replicated research trials at university and commercial farms and to help popularize the use of these systems. By the end of 2005, 33 growers had successfully used PTC and 15 had tried it on multiple commodities. Most growers found that PTC improved pest control, substantially reduced pesticide use, saved time and money, and found the system(s) simpler to use than their conventional pest management program (see section 5, Outcomes and Impacts). Forty publications on PTC were produced and 54 presentations were conducted throughout the Northeast.

Performance Target:

PERFORMANCE TARGETS
Of the 800 New England vegetable growers that will learn about PTC, at least 26 growers will adopt PTC on one (16 farms) or more crops (10 farms); will reap pesticide reduction, pest control, crop quality, environmental, safety, time, profit or personal satisfaction benefits; and upon completion of the project, their farms will serve as examples of a novel whole-farm systems approach to pest management.

By 2004, at least 27 CT, MA, NH, and VT growers had installed PTC systems on 8 different commodities on over 170 acres of crops. Ten growers used PTC on multiple commodities. Most growers found that PTC improved pest control, substantially reduced pesticide use, saved time and money, and was simpler to use than their conventional pest management program (see section 5, Outcomes and Impacts). In a single year, over 1,600 growers attended conference talks, over 2,100 attended poster sessions, and 45,000 received newsletter, magazine, and manual articles on PTC. In 2005, growers installed an additional 280 acres of PTC on cucumbers, butternut squash and pumpkins. All performance targets have been exceeded.

Cooperators

Click linked name(s) to expand
  • Steve Bengtson
  • Gordon Burson
  • Andrew Cavanagh
  • Nelson Cecarelli
  • Robert Durgy
  • Kristen Wilmer

Research

Materials and methods:

A series of introductory, twilight, farm tour and discussion group meetings, along with conference talks, fact sheets, manuals and articles were used to educate growers about PTC and to recruit implementers. Mentor growers hosted twilight meetings to demonstrate PTC to interested growers. Four to ten growers installed PTC in commercial summer squash, cucumber and butternut fields, which were compared with a similar number of fields/farms managed conventionally. Educators assisted growers throughout the implementation, crop production and evaluation process. Growers suggested improvements and new trap crops that were tested in replicated trials at the UConn and UMass Research Farms.

Most of these activities were successful at engaging growers and actually exceeded our expectations. However, the initial introductory meetings did not draw enough growers to recruit participants for the commercial field comparisons. As a result, some farmers were recruited directly to participate and were asked to install PTC plantings.

RESEARCH EXPERIMENTS (METHODS)
Experiment I – Commercial Fields Comparison – Summer Squash
This experiment was conducted to evaluate if PTC could protect large commercial summer squash plantings from cucumber beetles. In 2003, 6 CT growers installed a trap crop perimeter of Blue Hubbard squash around 7 commercial plantings of green (zucchini) and yellow summer squash, ranging in size from 0.25 to 6 acres. Six (yellow) or 7 (green) conventional summer squash plantings of similar size, on different farms, were used as control plots. Plots were planted between late May and late July. In PTC blocks, growers used foliar insecticide (Sevin, Asana or Pounce) applications on the trap crop row when beetles were first detected, and made repeat applications if and when more live beetles were detected until bloom. Conventional plantings were treated for beetles with similar insecticides (full-field applications) as the growers saw fit.

Data were recorded weekly prior to bloom, from 25 randomly selected plants located along lines (transects) through the length of the planting, in both the trap crop along the edge of the field, and in the main summer squash crop. Summer squash plants were sampled along a line approximately half the distance to the center of the planting. All but one field contained both green and yellow squash. Plants were sampled along 4 transects in most fields; in the trap crop along the lengths of the block (2 outside rows), and half way to the center in both the green and yellow squash portions (total of 100 plants sampled). Only 50 plants were samples in the lone field with a main crop of only green squash. In conventional fields, transects were in both the outside rows of summer squash along the length of the planting and half way to the center in both the green and yellow squash (4 transects).

Dead and live cucumber beetles were counted on, and immediately under, the plants each week prior to bloom. Two types of defoliation ratings were recorded. Beetle feeding on cotyledon leaves was recorded as present or absent on each plant. Also, the defoliation on all true leaves was ranked from 1 to 5 (increments of 20% defoliation) or absent (0).

The mean live and total beetles, percent plants with cotyledon feeding, and percent defoliation per plant for conventional and PTC fields were analyzed using the Mann-Whitney U-test. The ratio (proportion) of plants with beetles for both the Blue Hubbard and summer squash in the trap crop plots, or the edge row and the inner transect in the control plots, were analyzed using a Chi-square test. Separate analysis were conducted for the green and yellow squash.

Experiment II – Commercial Fields Comparison – Cucumbers
This experiment was conducted to evaluate if PTC could protect large commercial cucumber plantings from cucumber beetles and bacterial wilt. In 2003, 4 CT growers installed a trap crop perimeter of Blue Hubbard squash around 5 commercial plantings of cucumbers, ranging in size from 0.5 to 4 acres (total of 6.5 acres). Five conventional cucumber plantings of similar size (0.5 to 7 acres), on different farms, were used as control plots (total of 10.7 acres). Insecticide applications were made as described for the summer squash trial except that the following materials were used during the course of the experiment: Sevin, Asana, Pounce, Thiodan and Diazinon. The experiment was repeated in 2004 with 6 commercial plantings of each treatment.

Sampling was conducted in a similar manner as in the summer squash trial, except that only 2 transects (total of 50 plants) were used in each plot; along the trap crop (PTC plot) or edge row (control plot) and half way to the center. The Mann-Whitney U-test and Chi-square test were used to analyze the data as described above.

Experiment III – Commercial Fields Comparison – Butternut Squash
This experiment was conducted to evaluate if PTC could protect large commercial butternut squash plantings form cucumber beetles. In 2004, 6 MA growers installed a trap crop of Blue Hubbard around 6 commercial plantings of butternut squash, ranging in size from 1.5 to 5.5 acres. Three PTC growers treated the trap crop with the foliar insecticide Sevin, when the beetles first appeared, and again if they found an average of 1 live beetle per plant. The other 3 PTC growers applied Admire in the furrow at planting for the trap crop row only. One Admire PTC planting failed due to wet weather, which left just 5 PTC fields in the experiment. Six conventional plantings of butternut, on different farms, were used as control plots. Three entire control fields were treated as needed with Sevin, while Admire was applied at planting to the entire field on 3 other farms.

Twenty-five plants in the border and 25 plants in the main crop were selected for sampling in each field. Plots were scouted weekly for beetles and defoliation, as described in the summer squash trial above, until the vines started to run. Data were transformed (log +1) and tested for differences between treatments using a General Linear Model. Means and significant interactions were separated using LSMeans.

Experiments IV – UConn Research Farm PTC Trial – Summer squash 2003-2005
This experiment was conducted to verify and quantify the effects of PTC in a controlled situation. All plots consisted of 66 plants, in 6 rows, with 4 feet between rows and 2 feet between plants (20 by 20 foot square plots). In 2003, four treatments were used: 1) unsprayed control of all ‘Sunray’ summer squash, 2) summer squash surrounded by a single row of Blue Hubbard, 3) all summer squash with the outer row sprayed as needed, 4) summer squash surrounded by a single row of sprayed Blue Hubbard. In 2004 and 2005, the second and third treatments were dropped and a single treatment substituted: all summer squash plants with the whole plot sprayed as needed. Sevin was used as an insecticide. Treatments were replicated 5 times in 2003 and 4 times in 2004 and 2005 in a RCBD. Plots were arranged in two parallel rows and spaced 50 feet apart.

In 2003, excessive precipitation delayed transplanting until the end of June. Three-week- old seedlings were transplanted on 30 June and Sevin was applied in treatments 3 and 4 on 1, 7 and 14 July. In 2004, transplants were put in on 25 May and plots needing sprays or perimeter sprays were treated with Sevin on 2, 9, 16 and 23 June, and with Ambush for squash vine borer on 30 June and 7, 14 and 21 July. In 2005, transplants were set on 30 May, and Sevin was applied on treatments where appropriate on 3, 10 and 17 June. Five random plants from the perimeter and from the center crop were sampled twice prior to bloom for live and dead beetles, cotyledon injury, and the leaves were rated for defoliation (scale 0-5). Plants were samples for beetles and defoliation data in 2003 on 10 and 28 July, in 2004 on 16 and 24 June, and in 2005 on 6 and 20 June. Fruit were harvested and weighed in 2003 on 5, 11, 18 and 27 August; in 2004 on 8, 13, 15, 18 July and 2 August; and in 2005 on 6, 9, 13, 15, 18, 21, 25, 29 July and 9 August. Wilting or dead plants were noted and mapped and assigned a mortality factor (i.e. bacterial wilt) on each sample and harvest date. Vines from 5 random plants in the perimeter and center areas were dissected and examined for squash vine borer larvae in mid-August. Data were analyzed using a Rank Approximation Transformation, followed by Tukey’s Honestly Significant Difference Test to separate mean ranks. A separate analysis was conducted on the center and perimeter areas.

Experiment V – UConn Research Farm PTC Trial – Cucumbers 2003-2005
Similar experiments were conducted for cucumbers as were described for summer squash in each year, except that there was no sampling for squash vine borer and plots were only separated by 20 feet. ‘Dasher II’ was used as the cucumber variety. In 2003, transplants were set on 26 June and perimeters in treatments 3 and 4 were sprayed with Sevin on 27 June, and 1, 7 and 14 July. In 2004, transplants were set on 26 May and lost to a frost on 31 May. They were re-set on 15 June and perimeters needing treatment were sprayed on 16 and 23 June. In 2005, transplants were set on 31 May and Sevin was applied to the appropriate plots on 3, 10, 17 and 27 June. Plants were sampled for beetles and defoliation data in 2003 on 3 and 24 July, in 2004 on 28 June, and in 2005 on 8 and 30 June. Cucumbers were harvested and weighed in 2003 on 4, 11, 19 and 25 August; in 2004 on 4 and 17 August; and in 2005 on 15, 18, 21, 25, 29 July and 1, 5, 9, 11, 13, and 16 August.

Experiment VI – UConn Research Farm PTC Trial – Acorn squash 2004
A similar experiment, with three treatments, was conducted for acorn squash as was described for summer squash in 2004, except that ‘Sweet Mama’ buttercup squash was used for the trap crop in the perimeter in place of Blue Hubbard on treatment 3. ‘Table Ace’ was used as the acorn squash variety and treatments were replicated 3 rather than 4 times. Transplants were set on 10 June and Sevin was applied to appropriate treatments on 16 and 23 June. Plants were sampled for beetles and defoliation on 25 June and fruit were harvested and weighed on 19 August.

Experiment VII – UMass Research Farm PTC Trial – Butternut 2003 & 2004
In 2003, a similar experiment with the same four treatments was conducted for butternut squash as was described for summer squash in 2003. Plots were direct-seeded with ‘Waltham Butternut’ on 10 June. Perimeters in the two treatments requiring sprays received applications of Sevin insecticide on 25 June and 2 July. Five random plants in the center and 5 in the perimeter of each plot were scouted weekly between 26 June and 10 July. Squash were harvested, sorted and weighed on 15 and 17 September.

In 2004, plot size was enlarged and treatment number was increased. The six new treatments included: 1) no border, no pesticide (control), 2) no border, Sevin on perimeter, 3) no border, Admire on perimeter, 4) Hubbard border, no pesticide, 5) Hubbard border, Sevin on perimeter, 6) Hubbard border, Admire on perimeter. Growers requested that additional Admire treatments be tested. Plots were direct-seeded on 26 and 27 May. All plots consisted of 144 plants, in 9 rows, with 5 feet between rows, 1.6 feet between plants (40 by 24 foot rectangles) and 50 feet between plots. Admire furrow drench applications to treatments 3 and 6 were applied at planting. Perimeter rows of treatments 2 and 5 were sprayed with Sevin on 11, 16 and 25 June and 1 July. Plants were sampled weekly between 7 and 29 June or until the vines began to run. Sampling was similar to what was described in the summer squash trial, except that 15 plants from the perimeter and center were sampled instead of 5. After beetles were sampled for the last time, border rows in all plots were destroyed to prevent reduced yields due to trap crop competition. Plots were thinned to 80 hills per plot on 7/20. Starting on 7/29, plots were monitored weekly for wilt. Fruit were harvested, sorted (marketable and culls), counted and weighed on 14 and 15 September. ANOVA analysis was conducted on ranked data and significant interactions were tested with SAS procedure pdiff. Tukey’s was used to test for differences between treatment means.

Experiment VIII – UMass Research Farm Trial – Brassica 2003 & 2004
This experiment was conducted to test the suitability of a PTC system to control 2 major pests in cabbage (‘Blue Lagoon’): diamondback moths and flea beetles. Two perimeter rows of trap crop were used instead of one: ‘Flash’ collards were used to attract the diamondback moth and ‘Summerfest’ komatsuna was used to attract the flea beetles. Four treatments were replicated 4 times in a RCBD. Plot size and treatments were similar to those described in the 2003 PTC summer squash trial except that, in the two treatments with the unsprayed or sprayed trap crops in the border, the plots were 22 x 22 foot squares, because of an outer row of komatsuna planted on 1 foot spacing. Cabbage, collard and komatsuna seedlings were transplanted on 4 June. Five plants in the perimeter row(s) and the center were sampled weekly for flea beetles, presence or absence of beetle feeding, and the number and size of diamondback moth, imported cabbageworm, and cabbage looper larvae. Fourteen cabbage heads were harvested from each plot on 19 August and rated for flea beetle and caterpillar damage.

In 2004, four-week-old seedlings were transplanted on 8 and 9 July. In two treatments without trap crops, the cabbage plants were spaced 1.5 feet apart in 9 rows 2.5 feet apart (plots 20 x 15 feet). Plots with the two perimeter rows of collards and komatsuna were 22 x 17 feet, with the komatsuma in the outer row at 1 foot spacing within the row. Fifteen plants in the center and perimeter of the all-cabbage plots, and in each of the two trap crops in the remaining plots, were sampled weekly for flea beetle presence and damage. In addition, beginning on 18 July, 3 yellow sticky cards were placed in the center area of each plot for 48 hours, every other week. Flea beetles on the traps were recorded to provide additional information on the beetles in the main crop. Sampling for caterpillar presence and damage occurred weekly after 22 July. In treatments where the perimeters were sprayed, applications of Sevin and SpinTor were alternated on a weekly basis. On 19 August, 14 heads of cabbage in each plot were harvested, weighed and assessed for flea beetle (presence/absence) and caterpillar damage (0-3 rating).

Experiment IX & X – UMass Variety Trials – Cucurbit Trap Crops 2004
In MA, two separate variety trials were conducted to assess the best possible cucurbit trap crop: one focused primarily on pumpkin varieties and the other on winter squash varieties. In trial IX, the following varieties were assessed: ‘Prizewinner’ giant pumpkin, ‘Valenciano’ white pumpkin, ‘Rocket’, ‘Cinderella’, ‘Big Max’, and ‘Magic Lantern’ pumpkins, ‘Speckled Swan’ gourds, and Blue Hubbard squash. Varieties planted in trial X included: ‘Red Kuri’, Blue Hubbard, ‘Ambercup’, Waltham butternut, ‘Table Ace’ acorn, ‘Bush Delicata’ and ‘Calabaza’ squash, as well as a standard gourd mix. A total of 21 plants per plot were seeded on 2 and 3 June, 1.6 feet apart in 3 rows spaced 5 feet apart (plots 10 x 7 feet). There were 10 feet between plots. Plots were replicated 4 times in a RCBD. Many plots were destroyed by crows and cutworms. In surviving plots, 5 plants were sampled weekly prior to bloom for live and dead beetles, cotyledon damage, and defoliation (leaves rated 0-5). Plots were monitored weekly for incidence of bacterial wilt beginning on 27 July. On 26 July, the number of squash bug adults, egg masses, and nymphs were recorded from 10 middle-aged leaves per plot.

Experiment XI – UConn Variety Trials – Eggplant Trap Crop 2003 & 2004
In 2003, 8 varieties of Oriental and Italian eggplant were screened to see which were the most attractive to eggplant flea beetles (FB) and Colorado potato beetles (CPB). The varieties assessed included: ‘Vittoria’, ‘Millionaire’, ‘Ichiban’, ‘Little Fingers’, ‘Neon’, ‘Orient Charm’, ‘Orient Express’ and ‘Megal’. Twenty-one plants of each variety were planted in 3-row plots on 11 June. Plants were spaced 2 feet between plants within rows and 4 feet between rows. There were 10 feet between plots. Each treatment plot was replicated 5 times in a randomized complete block design. On 22 June, 5 plants per plot were sampled for FB, leaves with FB feeding, and FB holes per leaf (2 leaves per plant); CPB adults, larvae and egg batches, leaves with CPB feeding, defoliation per damaged leaf, and defoliation per plant.

In 2004, 3 varieties of eggplant (Vittoria, Millionaire and Ichiban) were re-tested along with ‘Classic,’ a traditional variety, as the control. Plots were planted as described above on 21 May. On 3 June, 5 plants per plot were sampled for FB and FB feeding. On 22 July, all surviving plants (9-17 plants/plot) were sampled for CPB and CPB feeding as described above. In each year, data were analyzed using a Rank Approximation Transformation, followed by Tukey’s honestly significant difference test to separate mean ranks.

Experiment XII – UConn Variety Trials – Cucurbit Trap Crops 2004
In 2004, two buttercup squash (Cucubita maxima) were compared to Blue Hubbard to see if we could find a more attractive trap crop. The experimental design, as well as, plant and plot spacing were similar to the eggplant variety trial above. Plants were direct seeded on 14 June. On 21 June, 5 plants per plot were sampled for cucumber beetles, leaves with feeding damage, defoliation per leaf, and the number of wilted/dead plants.

Experiment XIII – UMass Variety Trial – Brassica Trap Crops 2004
In 2004, 8 Brassica varieties were trialed to see which would be the most attractive to flea beetles and 3 caterpillars: diamondback moth larvae, cabbage loopers and imported cabbageworms. The varieties tested included: ‘Blue Lagoon’ cabbage, ‘Flash’ collards, greasy greens, pak choi, sweet alyssum, ‘Green Wave’ mustard, gai lan, and ‘Summerfest’ komatsuna. All varieties were transplanted on 6 June as 5-week old transplants. Each plot contained 3 rows of 7 plants each, spaced 1.5 feet between plants within the row and 2.5 feet between rows. Plots were 5 feet apart and each treatment was replicated 5 times. Five plants from the center of each plot were scouted weekly for insects. In addition, on 22 and 29 July, flea beetle leaf damage was ranked into three categories: 0 holes, 1-5 holes, greater than 5 holes.

Research results and discussion:
OUTCOMES AND IMPACTS

We have provided SARE the names and contact information of 33 New England growers who successfully installed PTC systems on at least 450 acres of vegetables in the last 3 years. Fifteen growers claimed to be using the system on two or more commodities. An additional 3 growers have reported failure with the system, either because they had no cucumber beetle population to control or because they had too many beetles and the system was overrun (improper instillation or maintenance may have been a factor in one case). Of these 36 growers, 23 filled out evaluation forms for one or more commodities, representing 210 acres of vegetable crops protected by PTC. Of the growers who answered the survey:
*96% claimed they reduced their pesticide use by using PTC
*96% claimed they improved their pest control using PTC
*61% claimed they reduced their crop damage and improved their yields using PTC
*83% claimed that PTC reduced adverse environmental impacts on land and water
*91% claimed that PTC reduced personal/personnel exposure to hazards
*70% claimed that PTC saved them time, 30% said it took the same amount of time
*87% claimed that PTC cost them less than conventional methods (by up to $3,810/acre)
*96% described their satisfaction level with PTC as “satisfied” to “thrilled”
*91% claimed they would continue to use PTC in the future (plus one said maybe)
Other benefits that MOST PTC growers rated highly on their farm included: improved/easier/faster monitoring, reduced risks from secondary pest outbreaks, improved public perception, reduced re-entry and day-to-harvest intervals, reduced potential for chemical crop residues at harvest, and reduced liability exposure. Growers also mentioned the following benefits of PTC: improved scouting and timing, less mechanical damage from sprayer, ease of pesticide application, deer control with the trap crop, and peace of mind due to improved confidence that they were controlling the pests.

In 2004, 9 Connecticut and 1 New Hampshire cucurbit grower saved 96% of their insecticide use by switching to PTC. They saved an average of 1.8 pounds of active ingredient per acre on over 152 acres. Nine of these growers provided crop quality/quantity estimates and cucurbit prices (total of 96.5 acres), except for pumpkins, and saved 18% of their crops (summer and winter squash and cucumbers) using PTC. Gross revenue increased by a total of $105,930, or an average of $1,098 per acre or $11,770 per grower.

In 2003, 5 Connecticut growers reduced their use of insecticide active ingredient for pepper maggot control by 0.7 pounds per acre (90%) by switching to PTC on just over 19 acres of peppers and eggplant. They saved 11% of their crop using PTC, worth a total of $21,368, or an average of $1,110 per acre, or $4,274 per grower.

Over 4,000 Northeastern growers have attended conference talks and twilight meetings about PTC in the last 3 years. Another 8,800 people attended poster sessions where PTC displays were presented and over 46,000 received publications with PTC information or recommendations. The P.I.’s have been contacted by farmers and researchers as far away as Oregon, Canada and Australia concerning PTC. Extension educators, private consultants, researchers and other educators in CT, MA, ME, VT, OH, FL, NJ, NY, Ontario, Quebec and Nova Scotia have all written about or published material on perimeter trap cropping. Numerous gardeners have also mentioned that they are using PTC at home (not always correctly, but they seem to be happy with the results).

EXPERIMENTAL RESULTS AND DISCUSSION

Experiment I – Commercial Fields Comparison – Summer Squash

When beetle infestations and defoliation were compared on plants in the main crop area (centers) of conventional commercial yellow summer squash fields (control) and PTC fields, there were no significant differences between the number of live beetles per plant, total beetles per plant, percent defoliation per plant or percent of the plants with cotyledon feeding. Although the total beetles per plant were not statistically different for the two treatments, beetle populations in the control plots often exceeded the action threshold for sprays (1 beetle/plant) and never approached the threshold on the summer squash in the center of the PTC fields. Results were similar for the green squash (zucchini) except that there was significantly less defoliation in the PTC fields than in the control fields.

In the PTC fields, there were 2 to 2.6 times as many infested plants in the trap crop row as in either the green or yellow squash. In control plots without a trap crop, the percent infested plants in the edge row and mid way to the center of the field (center) were about equal.

Results indicated that beetles were evenly distributed across the control fields but were much more concentrated along the trap crop row in the PTC fields. Beetle populations were statistically similar for the main crop in both treatments, but never reached action thresholds in the PTC plot. There were an average of 1.2 full-field sprays to control cucumber beetles in the conventional fields and 1.9 applications (to only the trap crop) in the PTC fields. By using PTC, insecticide use was reduced by 83%, compared with hypothetical fields of similar size with 1.2 full-field sprays.

In summary, PTC reduced defoliation while simultaneously reducing insecticide use, by concentrating the beetles on the trap crop plants. The main crop in the PTC fields were protected just as well or better than squash sprayed multiple times in the control (conventional) fields.

Experiment II – Commercial Fields Comparison – Cucumbers
Statistically in 2003, the number of live and total cucumber beetles per plant in the center of the conventional commercial cucumber fields (controls) and PTC fields were similar. However, with the exception of one farm, the beetles never reached the action threshold in the PTC fields and often exceeded the spray threshold in the conventional fields. There were significantly more plants with injured cotyledon leaves and higher levels of defoliation in the control fields compared to the PTC fields.

In 2004, the number of beetles per plant was low in both the PTC and control plots. However, there were almost 5 times as many plants with cotyledon feeding in the control plots as in the PTC plots.

In 2003 and 2004, there were 4.8 to 5.3 times as many trap crop as main crop plants infested with beetles in the PTC fields. In 2003, there were slightly more plants infested in the centers of the control plots than in the edge row, but in 2004, the infestations were similar across the conventional fields.

In summary, cucumber results were similar to the summer squash results. Beetles were fairly evenly distributed across the control fields but were much more concentrated along the trap crop row in the PTC fields. Beetle populations were similar for the main crop in both treatments each year. Insecticide use was reduced by 69% in PTC fields in 2003. There was an average of 2.2 full-field sprays to control cucumber beetles in the conventional fields and only 1.8 applications to the trap crop in the PTC fields. Also, 2 half-acre PTC cucumber fields on one farm required 1 or 2 full-field sprays. At first, we viewed 1 or 2 full-field sprays on a PTC field as a failure. Until the grower informed us that he was delighted with the results because he normally applies 4 sprays and losses all his cucumbers.

Again, PTC reduced defoliation, while simultaneously reducing insecticide use, by concentrating the beetles on the trap crop plants. In most cases, PTC reduced damage without spraying the (main) crop.

Experiment III – Commercial Fields Comparison – Butternut Squash
The number of beetles were higher in the Blue Hubbard borders than in the PTC main crop, regardless of what chemical (Admire or Sevin) was used to treat the trap crop. Most of the beetles in the PTC borders were dead. As in the previous two experiments, beetle distribution was similar in the border and main crop sample areas of the conventional fields. The beetle density was similar in the main crop for both treatments, despite the fact that the main crop was sprayed in the conventional fields and left unsprayed in the PTC fields. Similar results were obtained in 2003 using only foliar insecticide applications.

We also noticed that during the critical initial colonization of the field, the relative distribution of the beetles was different in the PTC fields from the conventional fields. In the conventional fields the beetles spread out through the field almost immediately. Beetle numbers were the same in field edges as in the center. In the PTC fields, most of the beetles stayed in the borders on the Hubbard. This means that during the time when the plants are most sensitive, at the young seedling stage, there were actually less beetles on the butternut protected by a PTC system than their were on the conventional butternut. After the conventional fields were sprayed, the beetle numbers on the PTC and conventional butternut evened out, but that initial protection can be critical to reduce direct damage to the seedlings and transmission of the bacterial wilt organism.

Experiments IV – UConn Research Farm PTC Trial – Summer squash 2003-2005
The most important comparisons in this type of experiment are between the main crop sample areas (center of plots) in different treatments. Main crop comparisons will be emphasized because they show how well the perimeter treatments work to protect the cash crop, which is really what the experiment was designed to investigate. Comparisons between the trap crop and main crop are interesting, but are like comparing “apples to oranges.” However, just to satisfy the reader’s curiosity, there were always far more beetles and damage on the trap crop than on main crops (centers) in the PTC experiments.

In 2003, beetle populations were low due to delays in planting caused by rainy weather. There were no significant differences on sample date 1 (10 July). For sample date 2 (28 July) in 2003, there were significantly more leaves with feeding injury on center plants in the control plots than on either of the treatments with a sprayed or unsprayed trap crop in the border.

For both 2004 sample dates, the main crop in the center of PTC plots had significantly fewer beetles and damage than plants in the center of control plots. The PTC plots had similar levels of leaves with feeding injury and total plant defoliation as the sprayed summer squash plots. PTC did not control squash vine borer, which contradicts a 2002 pilot study.

In 2005, there were no differences between the number of beetles per plant in the centers of PTC and control plots on either date. However, leaf feeding and defoliation per plant were reduced in the PTC plots compared with the control.

In summary, PTC consistently lowered beetle damage compared with control plots, sometimes to levels that were comparable to sprayed summer squash plots.

Experiment V – UConn Research Farm PTC Trial – Cucumbers 2003-2005
Beetle damage was lower in the center of PTC plots (sprayed BH perimeters) than in control plots during the first sample period in both 2003 and 2005. The cucumber results were not quite as consistent as the summer squash PTC research farm experiment results, where the main crop damage in PTC plots was consistently lower than control plots.

In 2005, early season plant mortality differences from direct beetle feeding and bacterial wilt produced an increase in yield for the season for PTC plots compared with the control. Sprayed plots had the highest yields. In 2003, plots with sprayed Blue Hubbard perimeters yielded substantially, but not statistically, more cucumbers than other treatments. Plots were only separated by 20 feet due to space constraints, which may have increased variation within the experiment, and decreased the possibility of finding statistically significant differences. Nevertheless, these yield differences could be very important economically for a grower using PTC.

Experiment VI – UConn Research Farm PTC Trial – Acorn squash 2004
PTC plots had slightly less defoliation damage than control plots. There were not enough beetles or sample dates (data) in this experiment to draw any useful conclusions.

Experiment VII – UMass Research Farm PTC Trial – Butternut 2003 & 2004
In 2003, there were significantly more beetles in the Blue Hubbard borders compared with the main crop of butternut in the same plots. However, there was no difference for beetles on the main crop between plots with and without borders. There were no significant differences in percent plant defoliation between the centers of plots regardless of whether or not there was a Hubbard border or a border spray. Plots may have been too close together.

In 2003, butternut plots surrounded by Blue Hubbard yielded less than plots without the trap crop, due to competition from the larger perimeter vines. In larger fields on commercial farms this is not a concern because the amount of space occupied by the trap crop relative to the main crop is negligible. Vines were removed at bloom in 2004 to alleviate this issue in the small plot work.

In 2004, there were again more beetles in the Blue Hubbard than in either the perimeter or main crop butternut. Again, there were no differences in beetle numbers on main crops for plots with and without trap crop perimeters. Defoliation on insecticide treated plants in the border was lower than on unsprayed plants in the border. The main crop of butternut in the plots where perimeters were treated with Sevin had lower defoliation levels than the combined unsprayed perimeter butternut and Blue Hubbard plants. This was due to higher defoliation levels in the unsprayed Blue Hubbard border plants. There were no differences in fruit weight or number in 2004 when the trap crop plants were removed at bloom.

Experiment VIII – UMass Research Farm Trial – Brassica 2003 & 2004
There were more cabbage looper and diamondback moth larvae in the collard borders than in the cabbage borders, or in the main crop of cabbage with or without a trap crop around it. There were also more imported cabbageworm eggs in the borders, regardless of whether the borders were sprayed or not, and whether they consisted of collards or cabbage. This experiment showed that there is potential to use collards around cabbage (or possibly other cole crops) to control caterpillars, but failed to demonstrate any lower population on the main crop of PTC plots compared with control plots.

Experiment IX & X – UMass Variety Trials – Cucurbit Trap Crops 2004
In Experiment IX, there were significantly more beetles and higher levels of defoliation on C. maxima plants (Cinderrella, Big Max, Blue Hubbard, Valenciano and Prizewinner) than other Cucurbita species in the variety trial. Due to excessive plant destruction from crows and cutworms there was insufficient data to determine differences between individual varieties.

In Experiment X, the C. maxima cultivars (Ambercup, Blue Hubbard, Red Kuri) all had higher beetle counts than any of the C. moschata or C. pepo varieties. These variety trials confirm that most C. maxima varieties have the potential to serve as effective trap crops for most cucurbit crops.

Experiment XI – UConn Variety Trials – Eggplant Trap Crop 2003 & 2004
The Italian and Oriental varieties Millionaire, Vittoria and Ichiban experienced significantly more Colorado potato beetle leaf feeding and defoliation than the other 5 varieties in the trial. The CPB population was low and there were no differences between actual CPB numbers. There were no differences between the varieties for flea beetles or FB damage.

In 2004, Ichiban had higher infestations of CPB than Classic and shows potential as a trap crop for this pest to protect traditional eggplant. Traditional eggplant (Classic) and Vittoria had similar levels of flea beetles and beetle damage, and more than Millionare and Ichiban. The Oriental and Italian varieties tested show little potential of success as a trap crop for FB to protect traditional eggplant. However, preliminary PTC tests showed that Vittoria had a lot of potential as a trap crop for FB around tomatoes.

Experiment XII – UConn Variety Trials – Cucurbit Trap Crops 2004
Blue Hubbard and Sweet Mamma had higher levels of defoliation per damaged leaf which may mean that they may hold the beetles for a longer period of time and thus be a slightly better trap crop than Autumn Cup buttercup squash. Blue Hubbard also experienced slightly higher levels of plant mortality than the buttercup varieties, which didn’t experience any death from direct beetle feeding or bacterial wilt. All three varieties are varieties of C. maxima species and would probably serve as effective trap crops for cucumber beetles around most other cucurbits.

Experiment XIII – UMass Variety Trial – Brassica Trap Crop 2004
Collards and cabbage (Brassica oleracea) were the most attractive varieties tested for imported cabbageworm. The oleracea as a group were more attractive than other species tested for diamond back moth. The B. rapa varieties pak choi and komatsuna were the most attractive for flea beetles.

Participation Summary

Education

Educational approach:

Our outreach/educational efforts included presentations at conferences, farm tours, twilight meetings, and poster sessions, combined with a series of fact sheets, newsletter/magazine articles, proceedings, manuals and journal articles. This outreach effort was meant to promote PTC to the growers, educators and researchers for the entire life of the grant and beyond. The strategy seemed to have succeeded as it resulted in several educators throughout the Northeast publishing PTC recommendations in various formats of their own. All together, 40 publications on PTC were produced and 54 presentations were conducted during the three years of the grant.

Additional Project Outcomes

Project outcomes:

Impacts of Results/Outcomes

ORIGINAL PROPOSED MILESTONES:
1) At least 40 growers will attend an introductory PTC meeting; learn about pest biology, epidemiology and migration patterns; and half will volunteer to test, explore and implement PTC systems. At least 12 will actually install/evaluate PTC systems in 2003.

Two introductory PTC meetings were conducted by the Extension Educators, on 2 and 8 April, 2003, in Vernon, CT and Chicopee, MA. These meetings were held later than intended and were sparsely attended (4 growers). Despite the late start in 2003, a total of 24 CT and MA growers attempted to install PTC systems on one or more crops: summer squash, butternut squash, cucumbers, peppers, pumpkins, cabbage and eggplant. Seven growers implemented PTC on multiple crops. Evaluations were conducted on at least 14 farms.

2) Replicated experiments in commercial fields and on research farms will be used to screen potential trap crop varieties, and test and verify 2-4 grower-designed/suggested PTC systems.

In 2003 and 2004, replicated PTC experiments were conducted on 4 crops (summer squash and cucumbers in CT, butternut squash and cabbage in MA) at the UConn and UMass Research Farms. In 2003 and 2004, 4 replicated variety trials were conducted in CT and MA to help determine the best trap crops to use in different systems. In 2003 or 2004 three PTC systems (summer squash-CT, cucumbers-CT, butternut-MA) were replicated on 4 to 6 commercial farms each. A similar number of farms, using the conventional multiple full-field spray approach, were also evaluated in the control groups.

3) Over 600 New England vegetable farmers will learn about PTC research/outreach results at conferences, other Extension/grower talks, and by newsletter/web site articles/fact sheets.

In 2003, at least 1,743 New England growers and 1,993 Northeast growers learned about PTC research and outreach results at conferences, other Extension/grower talks, and by newsletter/web site articles/fact sheets. Many more were exposed to the concept in poster display sessions.

In 2004, at least 1,679 New England growers learned about PTC at conference talks. Another 2,150 people attended poster sessions where PTC was explained, and over 45,000 people received newsletter/magazine/manual articles on PTC. Numerous educators and scientists learned about PTC by reading two articles in the Journal of Extension. Many more folks read about PTC on UConn, UMass, UVM and other web sites.

In 2005, 635 growers learned about PTC at conference talks while more than 5,900 people attended poster sessions and received publications where PTC recommendations were included.
4) Over 200 farmers will learn about PTC directly from mentor growers/Educators at twilight meetings and farm tours. An additional 14 growers will install PTC systems in 2004.

In 2003, 175 growers learned about PTC at 2 twilight meetings (10 July, Northford, CT, and 15 July, Sharon, MA) and at farm tours at the UConn (17 July) and UMass (13 August) Research Farms.

In 2004, 170 growers learned about PTC at 2 twilight meetings (1 July, Somers, CT and 14 July, Hadley, MA) and at a farm tour at Hampshire College (13 Aug, S. Amherst, MA). Additional growers tried PTC in 2004 and 2005 after hearing about it at twilight meetings or conference presentations, bringing the total number of documented PTC growers to 33 (approximately 450 acres). At least 15 growers are now using PTC on multiple commodities.

5) At least 20 implementers will attend post-season farmer-to-farmer discussion group(s) to help provide feed back to educators, and to form a post-project support group.

On 3 December 2003, 20 CT and MA growers and Educators met at the Sturbridge Host Hotel in Sturbridge, MA to discuss their 2003 experiences using the various PTC systems. Ideas were voiced which helped in writing new drafts of fact sheets with PTC recommendations. All attendees received contact information for all participants. A second farmer-to-farmer discussion group on PTC was conducted at the New England Vegetable and Fruit Conference & Trade Show at the Radisson Hotel in Manchester, NH on 14 December 2005. Approximately 35 growers and educators attended in 2005. Many were growers and researchers hoping to use PTC for the first time.

Economic Analysis

POTENTIAL CONTRIBUTIONS

Perimeter trap cropping is a redesigned crop production system that brings pest populations down to acceptable levels with a minimum of chemical intervention or ecological disruption. The technology used in PTC is simple, inexpensive and accessible to all farmers. It results in dramatic pesticide savings, reduced risks, improved crop quality, higher profits, and pest control that is comparable to that obtained with the best commercial insecticides. PTC involves simple changes that produce substantial advantages. Hopefully, it will serve as an example of how other effective pest management systems can be developed through simple adjustments in the production system. Most New England growers that have tried this system said they would continue to use PTC in the future, and hopefully, help spread the concept to neighboring farms. A partial budget economic analysis showed that growers in the 2003 CT study that used PTC on summer squash saved an average of nearly $900 wholesale and $2,600 retail per acre. We believe PTC will help growers maintain profitability, improve their quality of life, and achieve sustainability.

Farmer Adoption

FARMER TESTIMONIALS

Thirty-three New England growers successfully installed PTC systems on at least 450 acres of vegetables in the last 3 years. Fifteen growers claimed to be using the system on two or more commodities.

The following comments were all recorded on the PTC evaluation forms:

“It blew my mind to see the beetles flock to the perimeter rows!” Randy Blackmer, N. Grosvenor Dale, CT

“I was surprised at how simple a remedy it was and how efficient!” John Wolchesky, Pomfret, CT

“I think this is a very economical way to control pests.” John Boisvert, Hadley, MA

“Deer selected Hubbards over pumpkins.” “Hubbards sold well at my stand.” Bob McNamee, Tolland, CT

“I highly recommend it [PTC], especially for big commercial growers, you’re crazy not to do it!” Jimmy Futtner, S. Windsor, CT

“I was in and out of that field spraying in 5 minutes…its very simple.” “The more I use it, the more comfortable I am using PTC.” Steve Bengtson, Berlin, CT

“PTC works well and does its job, the key is you still have to do that scouting. I’m very happy with it.” “It helps to plant [the trap crop] on the edge of the black plastic mulch – it eliminates needing space for the trap crop.” Gordon Burson, Somers,CT

“It was easy and saved me on spraying and money.” “It was very helpful!” Dave Dougan, Manchester, CT

“My cucumbers were sprayed and sprayed and sprayed in the last two years and they were bitten from end to end…none sold…I can not get a crop of cucumbers [on my farm] without PTC!” “Its simple!” Nelson Cecarelli, Northford, CT

“Its good to have the experience with you showing us how to do it [PTC].” Doug Young, Woodstock, CT

“I enjoy having you come because I like the lessons you give.” Tim Janssen, Enfield, CT

“This year [pest control with PTC using Admire] was effortless!” Wally Czajkowski, Hadley, MA

“I’m happy using PTC.” Chip Beckett, Glastonbury, CT

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

FUTURE RECOMMENDATIONS

Additional PTC research is needed in the areas of organic applications, additional crop/pest combinations, cues involved in host finding and colonization, and the effect of trap crops on main crop pollination and yield.

Treatment plots in small plot studies must be spaced further apart in future experiments. The grant P.I.’s felt that cucumber beetle populations were drawn out of control plots to nearby trap crop plants in the small plot studies. This has the effect of artificially lowering the beetle level in the control plots, which is suppose to represent the natural background population. If very few beetles remain in control plots it eliminates the possibility that other treatments may suppress populations below the “natural level.”

Trap crop research poses unusual challenges. Space treatment plots too close and they may interfere with each other. Space them too far apart, and one risks testing treatments against completely different populations (pest levels). Also, because a successful experiment would involve control plots with many individuals per plant, while plants in the center of PTC plots would ideally be free of pests, data is unlikely to be normally distributed, even after transformation. Experimental designs should accommodate non-parametric statistical tests.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.