Natural pest management in New York high tunnel and greenhouse vegetables

2009 Annual Report for LNE07-262

Project Type: Research and Education
Funds awarded in 2007: $108,905.00
Projected End Date: 12/31/2010
Region: Northeast
State: New York
Project Leader:
Judson Reid
Cornell Vegetable Program

Natural pest management in New York high tunnel and greenhouse vegetables



Now in the third year of the project, scouting of vegetables in various tunnel and greenhouse crops continued. This year nine growers provided crop space for trials, with five of them being first time participants in the project. Weekly scouting took place at all locations to monitor pest populations. Once pest populations were detected growers were notified and had the opportunity to choose a natural pest control agent. In some situations the biological controls were provided by the program and in others the grower organized their own management strategy. As in previous years, there were some trials with outstanding biological control and others that did not perform at standards high enough for grower satisfaction. An on-farm demonstration meeting took place at a first-time cooperating tunnel.

The pests we dealt with during the 2009 growing season were aphids, thrips, and two spotted spider mites. Crops were include cucumbers, eggplant, beans, tomatoes, and peppers and greens.

Objectives/Performance Targets

Of the 80 farmers who attend demonstration farms and educational meetings as part of this project, 15 will adopt biological control of pests and diseases in greenhouse/high tunnel vegetable production within 3 years.


  • Interest from 5 new growers to the program

    Scouting performed by project leader and technician at 9 different cooperating sites.

    5 of these 9 farms presented and opportunity to demonstrate/trial biological control.

    1 of these farmers hosted 45 growers an on-farm demonstration meeting in August 2009.

    Technician made 85 on-farm scouting visits during the 2009 season.

    Over 100 growers attended a winter meeting (January 2009) that included industry, grower and university speakers. At this meeting the basics of pest and biological control were covered. Also, the results from the 2008 on-farm trials were presented.

    The PI presented project results to the statewide Organic Program Work Team, with teleconference sites in Long Island, Geneva, Albany and Ithaca, NY, reaching 60 faculty, extension educators and farmers.

    We have clearly made great progress toward our milestone “80 growers will attend winter meetings and/or one of 4 on-farm demonstration farms for biological control.” Previous milestones as listed in the original proposal are discussed in 2008 annual report.

    Progress toward our Performance Target is notable as some growers have begun to order their own biological controls or otherwise use natural controls such as resistant varieties. In 2010 we will collect data to assess attainment of this goal.

    One challenge we have faced is a disease called Brown Leaf Mold of tomatoes, caused by Fulvia fulva. Some growers have adopted resistant varieties to deal with this disease, however others do not want to abandon their preferred varieties such as heirloom or determinate types (without resistance). Growers report that copper fungicide sprays have not been effective. This disease deserves further attention in tunnel settings.

Impacts and Contributions/Outcomes

2009 on-farm results

Each of the nine sites that participated in on-farm trials during the 2009 season were rated on a scale of 0 to 5 based on the success of the biological control used to suppress pests. (0= biological control release failure, 3= pests were suppressed but not eradicated and 5=good pest control). Of the nine locations that were monitored, five had pest pressure requiring control. Each of these five sites had biological controls released, all with some level of success. Half of the locations had complete control with the use of biological agents, and the other locations had suppression of the pest, but not complete eradication. Brief summaries of each of the locations are included below.

Location: Penn Yan, New York
Crop: High Tunnel Cucumbers
Pest: Thrips
Biological Control: Amblyseius cucumeris
Dates on Farm: Weekly from May 11-July 28
Success Rating (0=failure to 5=control): 4.75

Monitoring of this high tunnel began on May 18. 2009 was the first year growing vegetables in this structure. Initial scouting showed very low numbers of thrips on the cucumbers and no other obvious pests in the tunnel. The following week, May 26, plots were set up. Numbers were taken from 4 replicates, consisting of 5 plants each, and 3 leaves per plant.
After week two thrips counts were on the rise and we decided to order a biological control. 20,000 Amblyseius cucumeris were released in the high tunnel on June 2 (week 3). The following week (week 4) numbers had increased from 2 thrips per leaf to 7 per leaf. However, this is often the case as it takes time for the biological controls to find their target, giving the thrips an opportunity to hatch out fresh nymphs and build their population. By week 5 thrips numbers had decreased by 50 percent. Cucumeris was doing its job. Week 6 showed another slight increase to 4 thrips per leaf so another 20,000 cucumeris were ordered and released on June 26. The thrips numbers continued to decline and were barely existent, less than one thrips per leaf, at week 10.

Having multiple crops in a high tunnel results in having multiple pest populations to deal with. Other problematic pests that have been identified in this particular tunnel were aphids on eggplant, cucumbers, and peppers, with the peppers and eggplant being the most sensitive. Biological controls and compatible pesticides where used to control these pests, with varying levels of success. Biological controls for the pest two-spotted spider mites were also released, and kept that pest at manageable levels. This farm was the site of an extension led farmer-to-farmer workshop.

Location: Hilton, New York
Crop: Greenhouse Tomatoes
Pest: Two-spotted Spider Mites
Biological Control: Phytoseiulus persimilis and A.californicus
Dates on Farm: Weekly from May 20 – Aug 4
Success Rating (0=failure to 5=control): 2.75

On-site scouting began at the end of May. Treatment blocks were set up consisting of 4 replicates of five plants each. Data was collected using a rating system, 0-9. A planted rated 0 would be perfectly healthy with no signs of mite damage, a rating of 9 signifies plant death due to mite damage.

In this particular greenhouse there were mites invading on the north and south edges. It was decided to care for these two sections separately, one side treated, the other untreated, to demonstrate biological control efficacy. Both sections had an established mite infestation at the time treatment began, June 26. Mite damage levels dropped slightly in the treated section for the first two weeks after treatment, and then slowly rose for the remainder of the season. Damage never reached yield threatening levels. Damage in the untreated section progressively rose over the course of the season, but also never reached yield threatening levels.

Location: Dundee, New York
Crop: High Tunnel Cucumbers and Tomatoes
Pests: Thrips and Two-Spotted Spider Mites
Biological Controls: A. cucumeris and Phytoseiulis persimilis
Dates on Farm: Weekly from May 11 – July 14
Success Rating (0=failure to 5=control): Mites in Cucumbers: 2.5; Thrips in Cucumbers: 4.0; Mites in Tomatoes: 3.5

Scouting of this high tunnel began on May 11. This year the tunnel housed tomatoes, cucumbers, and blueberries. Two-spotted spider mites started showing up on all crops around May 18. One week later it was clear this pest was on the rise and the biological control P. persimlis was ordered. At this time there was also an increase in thrips on the cucumbers thus A. cucumeris was ordered as well. Both natural enemies were released on June 2.

P. persimlils controlled the spider mites on the tomatoes, never causing any yield-reductions; however, they continued to increase on the cucumbers. Thrips levels on the cucumbers started around 0.3 thrips per leaf. After the release of cucumeris, thrips numbers dropped by fifty percent within one week. Eventually they began to creep back up, but never reaching more than the initial infestation level, and never becoming threatening to yields. However, two-spotted spider mites were not successfully controlled on cucumbers.

Location: Trumansburg, New York
Crop: High Tunnel Peppers
Pest: Aphids
Biological Control: Aphidius colemani and Aphidius ervi
Dates on Farm: Weekly from; July 7 – July 28
Success Rating (0=failure to 5=control): 5.0

This grower contacted us when their high tunnel peppers were invaded by aphids. Plots were set up on July 7, 4 replicates, 4 plants each. The number of aphids was counted on three leaves per plant. Initial data showed over 12 aphids per leaf. The biological control agents A. colemani and A. ervi were ordered and released the following week, July 10. On July 14 pest numbers had dropped to 2 aphids per leaf. Pest incidence continued to decline over the next two weeks to almost zero.

Location: Penn Yan, New York
Crop: High Tunnel Peppers
Pest: Aphids
Biological Control: A. colemani and A. ervi
Dates on Farm: Scouted post-release on June 15, 22 and 30
Success Rating (0=failure to 5=control): 5.0

In this circumstance the farmer scouted on their own and determined that aphid populations required control. Assistance with biocontrols was requested and subsequent scouting by program assistant found low-to-no populations.


Kathryn Klotzbach
Program Assistant
Cornell Vegetable Program
12690 Route 31
Albion, NY 14411
Office Phone: 5857984265