Organic Integrated Pest Management in High Tunnel Vegetable, Small Fruit, and Flower Production

2005 Annual Report for LNC04-245

Project Type: Research and Education
Funds awarded in 2004: $136,451.00
Projected End Date: 12/31/2006
Region: North Central
State: Missouri
Project Coordinator:
James Quinn
University of Missouri

Organic Integrated Pest Management in High Tunnel Vegetable, Small Fruit, and Flower Production


High tunnels are low tech and inexpensive unheated plastic greenhouse structures that allow for production of extended season, higher quality and greater yielding vegetables, small fruit and flowers. Organic production in this environment benefits from reduced disease pressure, as well as the potential for enhanced prices. Cost effective, safe, and practical methods to control pest pressure in these structures are being researched and evaluated. Field events will be held at on-station and on-farm locations and will allow multi-disciplinary team members to engage with producers. Extension programming is being addressed with a range of educational materials and outreach activities.

Objectives/Performance Targets

Research objectives:

Evaluate three organic IPM techniques on selected high tunnel crop production systems in on-station trials at four sites–

Double-cropping annual strawberry and vegetable production systems – Wichita, Kansas

Organic and conventional production systems for green leafy vegetables – Olathe, Kansas

Flower-based production systems – Mead, Nebraska

Extended-season production of warm-season crops – Columbia, Missouri.

[Organic IPM techniques include use of beneficial attractant perimeter crops, release of beneficial insects, and use of OMRI approved control products for pest problems.]

On-farm Objectives:

Evaluate organic IPM techniques identified through the research, or of current importance. An economic analysis will be preformed on the IPM techniques assessed positively by the grower-collaborators.


A series of field days were held in the fall of 2004 to promote university research and demonstrate producer practices with high tunnels. This provided an ideal format to educate producers about this project and receive input from them on the issues being investigated by the researchers. The field days, three at research stations and three at farms, were held at the following locations during the noted month:

Wichita, Kansas — October 5th
Lincoln, NE — October 6th
Kansas City, KS — October 13th
Westphalia, MO — October 21st
Columbia, MO — October 28th
Olathe, KS — November 8th

University of Missouri at Columbia

Research was conducted from the spring of 2004 until mid-summer of 2005. Research focused on two areas:

*Does the maintenance of beneficial attractant cover crops around a high tunnel reduce pest problems? Can insect attracting food sprays serve the same purpose?

*Can insect screening be effectively used without compromising the high tunnel air temperature?

(Any screening will restrict passive airflow)
Research on the interaction of cover crops, beneficial insects and insect food sprays was successfully implemented in 2004. Review of the samples for beneficial insects and their respective numbers is still being conducted by KSU Entomology/ James Nechols lab. The anticipated pests of focus were aphids and thrips; neither appeared in sufficient numbers during the year to cause any problems on tomatoes, peppers, zucchini, or potatoes. An unanticipated problem with the cover crops was the favorable habitat they created for voles. Control of voles became time consuming with the need of baits and traps to keep their levels tolerable. The issue of vole control and their habitat was discussed in the March 2005 issue of Growing for Market.

In April of 2005 two plots each of tomatoes (Fabulous & Sunbrite) and bell peppers (Lafayette) were established in four high tunnels, two with Econet B insect screen (US Global Resources) and two without. One plot of the tomatoes and peppers in each high tunnel was treated with organic insecticides weekly, and one plot of each crop received no treatment. Econet B screen was selected because it only restricted airflow by 5% and would prevent tomato fruitworm and European corn borer moths from entering. Whether the (1000 x 400 mm) mesh would restrict cucumber beetles was in question, and the tunnels also had cantaloupe plantings. Another question was whether the screening material would significantly raise the air temperature in the high tunnel.

Screening Results

1. Use of Econet B raised the air temperature about 5◦ F. While airflow is not reduced significantly, the screen reduces wind by 45%, thus reducing air movement in this passively vented situation. For crops enjoying warmer temperatures in the summer, like melons and tomatoes, this may be acceptable, but with crops like cucumbers, peppers and (most, if not all) salad crops, this would be problematic.

2. Tomato fruitworm damage was virtually eliminated in a screened tunnel where tomatoes were not cultivated the year before. In the tunnel where tomatoes were cultivated, fruitworm damage was just as significant (about 18%, see note below). While not conclusive, this lends credence to the suspicion that a protected environment can aide tomato fruitworm in successfully over wintering further north then they normally would survive. Tomato fruitworm moths were detected in traps set up at 5 points from south to north in Missouri about mid-May. Since fruitworm damage is often not noted until harvest approaches (harvest typically begins about mid-June), it is difficult to know if the caterpillars are from eggs laid by tomato fruitworm moths flying up from the south, or from moths that emerged from pupae in a high tunnel.

3. Presence of European corn borer (larvae) did not occur on the bell pepper fruit in screened or unscreened tunnels by September. The previous year this pest appeared beginning in August, which is typical of the pest moving from corn beginning to dry down.

4. Both striped and spotted cucumber beetles were able to slip through the screen, with the screen providing no reduction in cucumber beetle numbers. Smaller screen would be required. Typical window screen would be a readily available inexpensive source, but this would restrict airflow more significantly, and may not be compatible with summer temperatures and passive ventilation.

* A combination of the OMRI approved insecticides Pyganic 5.0 and Dipel (B.T.) applied weekly provided control of tomato fruitworm damage, taking about 3 weeks to provide good control (3% of marketable fruit damaged by the caterpillar). Without the insecticides 18% of the marketable fruit was damaged. Caterpillar damage was usually substantial enough for the fruit to be culled.

Kansas State University


A two-year study is under way to compare organic with conventional method to control two-spotted spider mites (TSM) on strawberries grown under high tunnel. Surround WP (60 g/L) is the organic treatment, while Zeal 72 WDG (2-3 oz/A) is used as a conventional control method.

In 2005, small infestation of two spotted spider mites (TSM) and few aphids were detected under high tunnel. Infestation of TSM was first observed in early April on the weeds between strawberry beds under high tunnel. Fortunately, no TSM infestation on strawberry plants was observed. In addition to the TSM under high tunnel, several beneficial insects, such as Ladybug larvae, Tachinid flies and lacewings were seen under high tunnel which might have prevented TSM from attacking strawberry plants. Strawberry harvest of high tunnel plants started early March. Sweet Charlie flowered and produced earlier than Chandler. Plants were harvested every two to three days. The 2005 harvest data show no significant damage from TSM infestation inside the high tunnel or outside (field plots). As expected, preliminary results showed yield was much higher under the high tunnel compared with that of field plots, data are yet to be analyzed.

Second experiment is underway for 2005/2006 season. Plants were not removed to study the effect of two year cropping system on population of TSM and to assess yield and fruit quality of two-year old strawberries under high tunnels. Observations of TSM infestation will continue this spring and yield and plant growth will be evaluated.


Six high tunnels were used for studies in 2005, which addressed salad green crops. Three of the tunnels are managed conventionally, and three are certified organic. The primary pest of interest was flea beetles, which are especially notable on arugula and tatsoi, but also damage most (leafy) salad greens from the Brassica group, like Mizuna, mustard greens, and Pac Choi. Pyganic 5.0 was used for the organic production system and a synthetic pyrethroid (permethrin) was used for the conventional system. Permethrin gave much superior control, with a treatment lasting at least one week, whereas the organic insecticide provided control for only a couple of days. For 2006, screening was being added to high tunnels to attempt control by keeping the flea beetles out.

University of Nebraska at Lincoln

A project was designed to investigate the effects of mowing on the movement of insects between the high tunnels and the adjacent vegetation. Beneficial predatory or parasitic insects were used for insect control in the high tunnels with one exception. Pyganic, an OMRI approved pesticide, was applied once to the lower two-thirds of sunflower stems to control stem borers. No other pesticides were applied.

The 2005 high tunnel (HT) insect monitoring project started on March 29, 2005 and ended on September 30.

Six high tunnels were monitored until May 5, when the beginning protocol was updated and only four high tunnels (HTs 1, 2, 5 & 6) were monitored after that time. There were two weeks when mowing was not done due to mower problems, two weeks when rain prevented an after mow and one week in October when there was not enough plant growth outside to warrant mowing. All other weeks a total of 16 sticky traps were counted; eight before mow and eight after mow (2 / HT, one inside and one outside, front and back of each). Vegetation species composition data was not collected in 2005. The vegetation is largely weedy species such as plaintain, crabgrass, some bromegrass, dandelions, henbit, chickweed, foxtails, and lambsquarters with about 25% bare ground. We will collect vegetation composition in 2006. The statistical design is a split-split plot with four replications. Preliminary analysis of the data is pending. We anticipate continuing the data collection in 2006.

A summary sheet was designed and the weekly totals entered by order under ‘Beneficials” or ‘Pests’.

Some of the problems encountered were:

1. Difficulty in identifying insects on the sticky trap where the adhesive obscures parts needed for identification. (Examples; antennae stuck to head so form not discernable; wings stuck together or to body as in Diptera vs. Hymenoptera).

2. Difficulty in determining whether similar species are beneficial or pests in look-alike groups.

3. Dirty traps (from soil and debris contamination after being put out) that make counting difficult and may enable insects to escape.

4. Un-represented or under-represented categories of insects that either don’t fly (caterpillars or other immatures) or are infrequent filers (stink bugs, ground beetles, grasshoppers, etc.).

5. Most types of insects captured on the sticky traps normally move by flying.

6. Climatic and physical conditions greatly affect the frequency of certain groups of insects. Examples: temperature, humidity, wind conditions, season (certain insects may only occur for a short period of time) and sky conditions (cloudy/sunny).

The 2005 HT project identifications were done on a predominantly insect Order basis with a small number of readily recognizable genera noted. This method has called attention to some potential problems with insect identifications and has provided a basis for determining protocols for future projects.

Impacts and Contributions/Outcomes

Six field days were conducted in fall of 2004 to raise awareness of the project, which impacted about 80 attendees. The Great Plains Vegetable Growers Conference held in early January of 2005 had a high tunnel workshop with 120 attendees. The featured speaker extensively addressed organic IPM issues in high tunnel production.

A critical component of the project is the on-farm testing by the collaborators and their subsequent participation in educational activities. One collaborator used Econet B insect screening to successfully keep grasshoppers out of a high tunnel in 2005. Warm weather cut flowers were grown in the tunnel during the late spring/summer, so slightly elevated temperatures were not a problem. The screening had an unforeseen benefit; during periods of high winds, the plants in the high tunnel with screening were protected sufficiently to prevent lodging.

Five collaborators were identified to evaluate organic techniques or tactics for pest control in 2006, summarized as follows:

1. Cut flowers — control of thrips with organic insecticides and use of a high quality sprayer that is battery powered and portable; control of root/crown rot with biofungicides facilitated in application with an injector.

2. Roses — control of spider mites with predator mites; control of powdery mildew with a new OMRI approved biofungicide.

3. Tomatoes — control of spider mites and tomato fruitworm with predatory mites and predator wasps, respectively.

Cole crops — control of caterpillars with predatory wasps.

Harlequin bugs — control with organic insecticides, including Neemix.

4. Tomatoes — improved control of tomato fruitworm with B.T. applied with a high pressure sprayer.

5. Salad greens — how to control flea beetles since rotenone is no longer allowed with certified organic production; use of insect screening and other organic insecticides, including various combinations.

Cucumbers — use of insect screening to prevent infestation.

In January 2007 these five collaborators will comprise the popular ‘farmer panel’ that has been the late afternoon session of the high tunnel workshop discussed above. They will each describe their results at that time.


James Nechols
Kansas State University
Department of Entomology
234 West Waters Hall
Manhattan, KS 66506
Office Phone: 7855324744
Laurie Hodges
Associate Professor and Extension Specialist
University of Nebraska at Lincoln
Department of Horticulture and Agronomy
377 Plant Scisnce Hall
Lincoln, NE 68588
Office Phone: 4024721639
Lewis Jett
State Vegetable Specialist
University of Missouri
1-31 Ag Building
Columbia, MO 65211
Office Phone: 5738827511
Melvin Brees
Farm Business Management
University of Missouri
143 Mumford Hall
Columbia, MO 65211
Office Phone: 5738822679
Sorkel Kadir
Research Assistant Professor
Kansas State University
Department of Horticulture
202 Throckmorton
Manhattan, KS 66506
Office Phone: 7855325420
Edward Carey
Associate Professor
Kansas State University
35125 West 135th Street
Olathe, KS 66061
Office Phone: 9138562335