Demonstrations of Sustainable Vegetable Pest - Crop Management: Fresh Market Sweet Corn

Demonstrations of Sustainable Vegetable Pest - Crop Management: Fresh Market Sweet Corn

Summary

The overall goal of this project is the education of farmers, Cooperative Extension specialists, extension agents, agribusiness leaders, and consumers about the need to adopt sustainable integrated pest management and integrated crop management (IPM/ICM) techniques. It will focus on fresh market sweet corn for the proposal period, but it is part of an overall vegetable educational effort that is ongoing. Four sweet corn pest and crop management systems (organic, IPM present, IPM future, and conventional) were defined and implemented on grower farms and a university research farm. Results showed differences among the four systems in terms of economics, pest control efficacy, and environmental impact. The conventional and IPM systems were most profitable, while the organic system showed least environmental impact. Information on the comparisons was disseminated to growers and others. In cooperation with Wegmans Supermarkets, consumers were informed of IPM practices on sweet corn, which were documented by growers. Twenty-five growers documented IPM practices and had usually reduced pesticide use.

Objectives
On growers’ farms demonstrate to farmers, extension specialists, extension agents, and agribusiness people the economic and environmental benefits of adoption of various IPM/ICM techniques as part of a more sustainable approach to vegetable production.

At New York State Agricultural Experiment Station (NYSAES) at Geneva, conduct one demonstration site to compare all defined pest management systems for fresh market sweet corn.

Collect and evaluate pest, pesticide use, economic, environmental impact, yield, and quality data to compare the systems at the farm sites and the university site.

Publicize the results of the comparisons through field days, presentations at grower meetings, and conventional and electronic publications.

Work with a major supermarket and its growers to implement sustainable practices for fresh market sweet corn; identify the corn to consumers as produced using IPM/ICM practices.

Methods
For the first two objectives, four systems were defined for pest and crop management by a group of extension and faculty at Cornell with knowledge of current and future sweet corn production practices.

In 1997 demonstrations were conducted with nine growers in the Syracuse area; in 1998 demonstrations were conducted with seven growers in the Buffalo area; and in 1999 demonstrations were conducted with eight growers in the Southern Tier/Corning area. The goals of these demonstrations were to familiarize the growers with IPM and organic production practices, and to enable the participating growers and the growers who viewed the demonstrations at field days to participate in Wegmans’ IPM-labeled sweet corn project (the final objective).

The site at NYSAES contained all four systems contiguous to each other and allowed for a rotational component to be introduced. Each system consisted of an early and a late planting of a half acre each year. Economics of each of the systems were evaluated by defining a typical farm profile growing fresh market sweet corn. Pest control efficacy, plant nutrition data, environmental impact, and beneficial insect data were collected. The systems were compared on the basis of economics, environmental impact, and efficacy of pest control. Results of the project were shown at numerous field days each year and were presented through talks and written publications. Working with Wegmans to identify IPM-grown sweet corn in their stores resulted in growers adopting many IPM techniques.

A more-detailed discussion of methods by objective follows.

Objective 1: On grower’ farms demonstrate to farmers, extension specialists, extension agents, and agribusiness people the economic and environmental benefits of adoption of various IPM/ICM techniques as part of a more sustainable approach to vegetable production.

For objectives 1 and 2, four systems (conventional, IPM present, IPM future, and organic) were defined for pest and crop management by a group of extension and faculty at Cornell with knowledge of current and future sweet corn production practices.

In 1997 demonstrations were conducted with nine growers in the Syracuse area, in 1998 demonstrations were conducted with seven growers in the Buffalo area, and in 1999 demonstrations were conducted with eight growers in the Southern Tier/Corning area. Demonstrations with growers in the Rochester area were conducted prior to the initiation of this project. The goals of these demonstrations were to familiarize the growers with IPM and organic production practices, and to enable the participating growers and the growers who viewed the demonstrations at field days to participate in Wegmans’ IPM-labeled sweet corn project (objective 5).

Grower sites varied in size from 1 to 5 acres. Each farm had either one or two of the systems present in a field with the intent to represent all four systems on some farm each year. In reality, the organic system could only be located on three grower sites, and the pest management practices we demonstrated on those farms were not different from the IPM future system sites. In grower fields, the IPM future insect management strategy was modified to include the use of Trichogramma ostriniae and Bacillus thuringiensis (Bt) for European corn borer management. Actual economic data were not obtained from growers since this is confidential information.

Several differences in system definitions between objective 1 and objective 2 occurred for a number of logistical reasons. In most cases the differences occurred as a result of grower decisions on management practices over which the investigators had no control. In general, grower cooperators experienced weather and planting conditions that caused them to change plans resulting in their being unable to implement the weed and rotational aspects of the different systems. Therefore, systems in grower fields were limited to the definitions for insect and disease management options. This was a major reason for conducting the more controllable demonstration in objective 2.

Objective 2: At NYSAES at Geneva, conduct one demonstration site to compare all defined pest management systems for fresh market sweet corn.

In general the conventional, IPM present, IPM future, and organic systems were defined based on the following criteria:

Conventional: practices that were thought by extension and faculty to be commonly used by fresh market sweet corn growers.

IPM present: practices that follow IPM elements (Petzoldt et al., 2000).

IPM Future: IPM present practices plus practices that may still be under research or expensive to implement.

Organic: following NOFA-NY guidelines (NOFA-NY 19__).

The site at NYSAES contained all four systems contiguous to each other and allowed for a rotational component to be introduced. Each system consisted of an early and a late planting of a half acre each year. At the NYSAES site, the IPM future system could not include the use of Trichogramma ostriniae because of the potential for interplot interference.

Objective 3: Collect and evaluate pest, pesticide use, economic, environmental impact, yield, and quality data to compare the systems at the farm sites and the university site.

Economics of each of the systems were evaluated by defining a typical farm profile growing fresh market sweet corn. Surveys were sent out to approximately 24 sweet corn growers during the 1997 growing season, with nine growers responding. To determine ownership costs, repair costs, and estimated life expectancy for each implement, the frequency of use on all production acres was calculated and general assumptions were made about practices (G. White, personal communication). A 30% premium price was used for organic system calculations.

For each system:

Pest control efficacy was evaluated using weekly scouting data for each identified pest in the system definitions and end-of-season evaluation of corn ears for pest damage.

Plant nutrition data were collected by means of annual soil tests performed by the Cornell Nutrient Analysis Laboratory and weekly pre sidedress nitrogen tests.

Environmental impact was evaluated by means of the environmental impact quotient (Kovach et al., 1992), amount of formulated product of pesticide applied, number of pesticide applications required, and amount of synthetic fertilizer applied.

Beneficial insect data were collected by means of scouting at specified dates through the season each year. Also five yellow sticky card traps were placed in each system location to trap natural enemies. Traps were changed approximately every 10 days, and the beneficial insects on them were counted and identified.

Objective 4: Publicize the results of the comparisons through field days, presentations at grower meetings, and conventional and electronic publications.

During each growing season of the study, a field day was held at the NYSAES site, and all interested parties observed the trial as it progressed.

On-farm twilight meetings were held each year at three growers’ farms as the season progressed. Presentations were made at winter meetings, including the New York State Vegetable Conference and various county meetings during each year of the project.

Reports were published annually in the “New York State Vegetable Project Reports Relating to IPM” document.

In 1997 a sweet corn IPM training school was held at the NYS Vegetable Conference to prepare growers for participation in the IPM labeling effort.

The project was highlighted in the New York State IPM Program Annual Report.

Objective 5: Work with a major supermarket and its growers to implement sustainable practices for fresh market sweet corn; Identify the corn to consumers as produced using IPM/ICM practices.

A series of meetings held annually with sweet corn growers, Wegmans Food Markets, and Cornell faculty and extension staff resulted in annual publication of the document “IPM Elements for Fresh Market Sweet Corn.” This document identified a list of IPM practices with points associated with each practice based on the priority the group gave to that practice.

In 1997 a sweet corn IPM training school was held at the NYS Vegetable Conference to prepare growers for participation in the IPM labeling effort.

During the on-farm twilight meetings each year, IPM elements were distributed and explained.

Growers kept records documenting their practice of IPM through the season.

Growers hired one of two identified independent IPM auditors to review their records annually. The auditors evaluated grower records against the practices in the IPM elements document and determined what percentage of points had been achieved by each grower for each field. A threshold of 80% of points was required to have the corn advertised in the store as IPM grown.

Growers from all of the three areas in the project supplied sweet corn to one or more of the 60 Wegmans supermarkets in New York and Pennsylvania. The sweet corn was identified in the supermarket displays as grown using the IPM practices described in the IPM elements. Informational materials (including a videotape explaining IPM, a brochure explaining IPM, and display materials explaining different aspects of IPM) were provided in the stores.

Results
Results indicate that there is not any one system of growing sweet corn in New York that is clearly better than another from all three viewpoints of economics, efficacy, and environment. There are clear advantages to certain systems based on what goals are to be optimized. IPM systems appear to be reasonable compromises that attain high economic return while reducing environmental impact.

All four systems were profitable on average, although the organic system was significantly less profitable than either the conventional or IPM future systems. The organic system was significantly more costly to implement than the other three systems, while the conventional system was significantly cheaper.

All four systems resulted in acceptable marketplace levels of insect damage for their particular markets. The organic system used significantly fewer pesticide applications and pounds of fertilizer than the other three systems. The organic and IPM future systems used significantly less active ingredient of pesticide and had significantly lower EIQ ratings than the other two systems. IPM present used significantly less pesticide and had a significantly lower EIQ than conventional. The use of vetch as a cover crop provided a large portion of the nitrogen required for a corn crop in the IPM future and organic systems.

IPM elements have been defined for fresh market sweet corn. These elements consist of practices that Cornell staff, growers, and retailers agree are critical to the practice of IPM in upstate New York on sweet corn. Each element has been assigned a point value depending on whether it is thought to be more or less important to the practice of IPM. Growers in the labeling effort have kept documentation of the practice or lack of practice of each element. The points have been totaled, and, to be labeled as IPM grown, a grower’s field must achieve at least 80% of the points available. A survey of 206 fresh market sweet corn growers conducted by the New York Ag Statistics Service in 1995 indicated that most growers were achieving between 40 and 70% of the IPM element points. The fifteen growers participating this project all achieved at least 80% of the points available, with some fields reaching 100%.

A more detailed discussion of the results by objective follows.

Objective 1: On growers’ farms demonstrate to farmers, extension specialists, extension agents, and agribusiness people the economic and environmental benefits of adoption of various IPM/ICM techniques as part of a more sustainable approach to vegetable production.

The conventional and IPM present systems had less than 1% damaged ears and less than $21 per acre loss to insects. The IPM future and organic systems averaged 4.78% damage—still under the commercially acceptable damage level—but suffered over a $100 per acre loss to insect damage. The conventional system on grower farms required two insecticides sprays on average using nearly 1 pound per acre of formulated product. The EIQ was nearly 9. By comparison the IPM future and organic sites required only 25% of the sprays and had an EIQ that was 17 times smaller.

In grower fields, the IPM future treatment insect management strategy was modified to include the use of Trichogramma ostriniae and Bacillus thuringiensis (Bt) for European corn borer (ECB) management. Pheromone traps for ECB, corn earworm, and fall armyworm were placed near each field to help determine optimal release times for the T. ostriniae, as well as the most effective Bt product for the pest complex present. In 13 of the 18 fields, where Trichogramma and Bt were used, commercially acceptable insect control (below 5% damage) was achieved. The average ECB infestation was 4.9% and only 0.6 Bt sprays were required based on scouting of the fields. Clearly T. ostriniae wasps made important contributions to the control of ECB in the grower demonstration fields.

The organic system was not implemented in grower fields in 1997. Rather than assume that organic growers encounter the same problems and pests as conventional and IPM growers of sweet corn, a survey of organic sweet corn growers was conducted to identify major problems and pests associated with organic production. The results of this survey are presented as narrative later in the report. During the current offseason, a plan for demonstrations with organic growers will be formulated based on the results of the survey.

Results of organic grower survey
To ensure that organic systems demonstrated in organic grower fields addressed problems relevant to organic growers, the first year of this project we surveyed organic sweet corn growers to identify constraints and concerns.

A comprehensive survey of fresh market vegetable growers in New York, New Jersey, and Pennsylvania conducted as part of a phase I grant from the national IPM Implementation Program shows that sweet corn is not widely grown by organic farmers. Of the 204 survey respondents growing sweet corn, 8.3% (17) were organic growers. While sweet corn was the most frequently grown crop for conventional/IPM growers responding to the survey, it ranked 20th for organic growers. We identified seven organic sweet corn growers in New York and were able to interview six. Five growers were in upstate New York and one was on Long Island.

· All the growers marketed all or part of their sweet corn through a CSA.
· Total acreages of sweet corn grown by the group ranged from 0.25–8 acres.

Nutrient management
· Sources of fertility included plowed down green manures or cover crops, on-farm-produced compost, and bagged organic fertilizers or commercially produced compost.
· Compost applications ranged from 10–16 T/A.
· Nutrient management information of interest includes more precise Cornell soil test that includes analysis of cation exchange capacity and micronutrients, better methods for estimating nutrient release from organic sources, and a method for tracking nitrogen availability.

Insect management
· ECB and/or corn earworm (CEW) was the most serious insect pest.
· Estimates of corn culled because of insect damage: upstate 0–10%, Long Island 10%–70%.
· Because CSA members accept more imperfections, up to 5%–10% of corn going to CSA members might be infested with ECB or CEW.
· Only one of the growers owned a sprayer suitable for sweet corn.
· A parasitic wasp for ECB control would be useful, but it would need to be cost effective.

Disease management
· Not generally a problem, although smut, rust, and Stewart’s wilt are in fields to some extent.

Weed management
· Weeds were a serious problem for two of the growers: one who plants in cool soil for a mid-July harvest, and one who does not have tractor-mounted cultivation equipment.
· All of the growers cultivate 2–4 times for weed control, using a wide variety of cultivators.
· Three of the growers interseed cover crops into the corn at last cultivation.
· Growers did not indicate a need for additional weed management information.

Based on the survey, we addressed organic grower’s pest management needs by demonstrating releases of Trichogramma ostriniae for ECB control in subsequent years.

Some grower fields in 1997 also presented the opportunity to test distress-call-based bird scare devices, since several growers had fields with bird pressure. The devices were placed in the field approximately 2 weeks before crop maturity, the time birds find the corn most attractive. In all three locations, fields with the bird scare device showed less damage than nearby fields of the same maturity without the bird scare device.

Objective 2: At NYSAES at Geneva, conduct one demonstration site to compare all defined pest management systems for fresh market sweet corn.

(Note: The first 2 years of the trial were funded by the New York State IPM Program.) The systems were compared on the basis of economics, pest control efficacy, and environmental impact. All four systems were profitable on average, although the organic system was significantly less profitable than either the conventional or IPM future systems. The organic system was significantly more costly to implement than the other three systems, while the conventional system was significantly cheaper.

All four systems resulted in acceptable marketplace levels of insect damage for their particular markets. While damage from the worm pests of sweet corn was highest in the organic, aphid levels were very low compared to conventional, perhaps as a result of low natural enemy populations in the conventional plots after pesticide applications. The organic system used significantly fewer pesticide applications and pounds of fertilizer than the other three systems. The organic and IPM future systems used significantly less active ingredient of pesticide and had significantly lower EIQ ratings than the other two systems. IPM present used significantly less pesticide and had a significantly lower EIQ than conventional. The use of vetch as a cover crop provided a large portion of the nitrogen required for a corn crop in the IPM future and organic systems.

The organic and IPM future systems consistently showed higher levels of a variety of beneficial insects. This higher level corroborates the observed lower populations of aphids observed in these treatments.

Results indicate that there is not any one system of growing sweet corn in New York that is clearly better than another from all three viewpoints of economics, efficacy, and environment. There are clear advantages to certain systems based on what goals are to be optimized. IPM systems appear to be reasonable compromises that attain high economic return while reducing environmental impact.

Objective 3: Collect and evaluate pest, pesticide use, economic, environmental impact, yield, and quality data to compare the systems at the farm sites and the university site.

The results presented for objectives 1 and 2 above compare the four defined systems for the farm and university sites in the terms described in objective 3.

Economic analysis: To evaluate the economics of each of the grower systems, it was necessary to define the typical farm profile growing fresh market sweet corn. Surveys were sent out to approximately 24 sweet corn growers during the 1997 growing season. Nine growers responded to the survey. The survey was designed to determine the size of their farm, diversity of crops grown, the type of equipment owned and used on the farm, and the practices used to grow fresh market sweet corn. The survey data were compiled and analyzed to describe a typical farm that grows fresh market sweet corn. A typical fresh market sweet corn farm has 275 total production acres with 100 acres planted to field crops, 100 acres to other vegetables, and 75 acres planted to sweet corn. This farm grows 10 different crops; the acres covered per year and hours of use for each implement are based on all 275 acres in crop production.

To determine costs, information from Barnes and White (1991) was updated based on the 1997 survey results. Other costs were monitored by keeping track of time in the field.

Objective 4: Publicize the results of the comparisons through field days, presentations at grower meetings, and conventional and electronic publications.

1997
Approximately 50 extension staff, agribusiness people, and growers attended the field day at NYSAES.

About 150 growers and others attended the Sweet Corn School at the 1997 NYS Vegetable Conference.

Various aspects of this project were presented at grower and scientific meetings in Burlington, Vermont (2/25/97); Bergen, New York (3/7/97); White River Junction, Vermont (4/3/97); Bradford, Ontario (4/9/97); Canandaigua, New York (4/29/97); Ithaca, New York (4/30/97); Washington, D.C. (6/27/97); Pittsburgh, Pennsylvania (8/6/97); Houston, Texas (8/29/97); Clemson, South Carolina (10/16/97); and Auburn, Alabama (11/5/97).

An IPM educational video was produced by Wegmans Food Markets and shown on local television and in stores.

Three extension twilight meetings during the growing season with a total of about 25 growers.

Willett, Lois Schertz. “Marketing Fresh Sweet Corn Grown with IPM Methods: An Econometric Analysis.” Selected Poster Presentation. American Association of Agricultural Economics, Toronto, Canada, July 27–30, 1997.

1998
Approximately 40 extension staff, agribusiness people and growers attended the field day at NYSAES.

Training sessions for sweet corn IPM were in Johnstown, Syracuse, and Buffalo for 25 growers.

Various aspects of the project were presented at grower and scientific meetings in Chicago, Illinois, WSSA, 2/98; AUTM, San Antonio, Texas, 2/98; Orange County, New York, 3/4/98; Ithaca, New York, 3/9/98, 4/18/98, 5/1/98, 6/24/98; Clifton Springs, New York, 4/28/98; IFFS, 8/11/98, Northampton, Massachusetts, 8/19/98, 9/19/98, 10/15/98; Geneva, New York and Atlantic City, New Jersey, 9/24/98.

The project was discussed at four extension twilight meetings in growing season with about 45 growers.

1999
40 in attendance at NYSAES sweet corn and snap bean field day

25 in attendance at four preseason IPM training sessions (two each in Niagara County and Southern Tier)

45 total in attendance at four extension field days (two each in Niagara County and Southern Tier)

2000 NYS Vegetable Conference, Syracuse New York: 150

2000 Cornell Agriculture in Service Education: 50

Objective 5:
Work with a major supermarket and its growers to implement sustainable practices for fresh market sweet corn; identify the corn to consumers as produced using IPM/ICM practices.

IPM elements have been defined for fresh market sweet corn. These elements consist of practices that Cornell staff, growers, and retailers agree are critical to the practice of IPM in upstate New York on sweet corn. Each element has been assigned a point value depending on whether it is thought to be more or less important to the practice of IPM. Growers in the labeling effort have kept documentation of the practice of lack of practice of each element. The points have been totaled and to be labeled as IPM grown, a grower’s field must achieve at least 80% of the points available. A survey of 206 fresh market sweet corn growers conducted by the New York Ag Statistics Service in 1995 indicated that most growers were achieving between 40% and 70% of the IPM element points. The 15 growers participating this project all achieved at least 80% of the points available, with some fields reaching 100%.

Sales of sweet corn at Wegmans stores using the IPM label have increased during the IPM labeling effort by as much as 50%, although it is unknown how much of the increase is attributable to the IPM label. Increased sales represent increased opportunity for New York sweet corn growers to sell product to consumers opening significant new markets.

Impacts and potential contributions
Continued adoption of IPM and organic practices described in these systems has the potential to reduce environmental impact as measured by the EIQ by at least 50%.

IPM labeling has the potential to increase adoption of IPM techniques in fresh market sweet corn from a 40%–70% level (based on a baseline survey conducted by NYS Ag Statistics Service) up to an 80%–100% level.

Adoption of IPM techniques has the potential to keep growers at least as profitable as they are using conventional techniques.

By banding herbicides in a 10-inch band over the row and subsequently using the routine cultivation/sidedress operation to control weed between the rows, we have reduced herbicide rates by about 60%.

To make Trichogramma releases economically feasible (starts at early tassel stage), Bt materials should be used to kill ECB larvae that are present when the Trichogramma releases begin.

The ZeaLater method of controlling CEW for late organic corn has potential for small acreages on farms that do not own sprayers and perhaps larger farms, if labor is available.

Thirty farmers in the IPM labeling phase of this project have adopted at least 80% of the IPM techniques described in the IPM present system. This represents well over 1,000 acres of sweet corn. Other growers have also adopted IPM practices but have not spent the time documenting the adoption.

A survey of 206 fresh market sweet corn growers conducted by the New York Ag Statistics Service in 1995 indicated that most growers were achieving between 40% and 70% of the IPM element points. The 30 growers participating in this project all achieved at least 80% of the points available, with some fields reaching 100%.

Collaborators: