Over the past three years, the High Tunnel Research and Education Facility (HTREF) has conducted extensive on-farm research evaluating the use of predator and parasitoid insects to control target pests on Solanacous crops, those grown most frequently in high tunnels in the Mid-Atlantic region. Insect scouting was conducted weekly throughout the growing season in each year, data was collected, recorded and compiled. Grower cooperators were supplied with transplants, beneficial insect shipments, equipment and supplies needed to conduct scouting and extensive training and consultation was provided by PSU researchers on a monthly basis or as requested by the grower. The outreach of this project was extensive, with research findings and general overview’s of biological pest management presented at a variety of professional and lay meetings, tours and demonstrations. Surveys were conducted to help gauge the knowledge of biocontrol that our target audiences possessed and evaluate where more information was needed. The culmination of the project is a 50-page manual designed specifically for high tunnel growers to help them in implementing biological pest management practices on the farm.
High tunnels are increasingly used for season extension throughout the country. The cultural management of the high tunnel environment falls somewhere in-between greenhouse and field production. Research has demonstrated the use of bio-controls or predatory and parasitoid insects to control pest populations in greenhouses to be effective and beneficial in decreasing and eliminating the use of chemical pesticides. Nowhere is this more evident than in Northern Europe. Prior to the commencement of our project, no research has been conducted on the use of ‘natural enemy’ species in the high tunnel environment whereby both beneficial and pest insects have ample opportunity to move in and out of the environment via the roll-up sides used for the ventilation of the structure.
The goal of our project was: 1) to evaluate the use of predatory and parasitoid insects for pest control in the high tunnel environment by conducting extensive research and demonstration at the High Tunnel Research and Education Facility (HTREF) in Rock Springs, PA and 2) conducting on-farm research in conjunction with two grower cooperators in the southeastern and northwestern part of Pennsylvania to assist in determining the ease of which these practices can be adopted by growers. Information has been and will be disseminated at presentations given throughout the region at professional meetings and workshops as well as at field days and Extension In-Service Training Days held at our research farm as well as at our grower cooperators farms. At the end of the project, all of our data will be coordinated and published in an informative pamphlet and distributed to our stakeholders as well as made available to SARE for distribution to interested growers.
1) Provide high tunnel growers with a method for decreasing or discontinuing the use of pesticides while maintaining or increasing their farm profits.
In 2002, Carol Glenister of IPM labs, Locke, NY visited the high tunnel facility in the Spring to gain a firsthand perspective of our cropping environment and the agricultural production adjacent to the high tunnels that would impact pest and predator populations in high tunnels. In year one, we determined crop varieties, potential planting dates and scouting methods with our grower cooperators. Visits were made to each cooperator’s farm for training and consultation and cooperator’s visited our facility for further training and to gain first hand knowledge of our cropping/scouting and cultural management systems.
In 2003, scouting procedures for insect monitoring in high tunnels were refined from experienced gleaned from the first year of data collection. In year two, another season of data was collected at the HTREF as well as at our grower cooperator sites in Holtwood, PA and Brookville, PA. Several releases of Encarsia formosa were made at Cedar Meadow Farm in Holtwood where student interns participated in much of the scouting and communication with the SARE Field Project Coordinator. Because of previous spider mite infestation, releases of natural enemies were also made independently of our project which focused in year two exclusively on the management of aphid and whitefly. Cedar Meadow farm was working in conjunction with Cathy Thomas, the state IPM coordinator to help manage spider mite infestations. Although an effective level of whitefly control was believed to be achieved, our grower cooperator felt it was urgent to spray a broad spectrum insecticide to control an unusual stink-bug infestation (this pest is not normally a significant problem in tomato crops in our region, however 2003 witnessed several outbreaks in the Southeastern part of PA). Despite weekly communication with our grower, he made the choice to spray without any consultation with the high tunnel project manager. Due to the damaging effect of the insecticide, the study was terminated in early September. No releases were required at our Brookville grower’s site; they have a history of not spraying insecticides and believed that they actually achieved sufficient control of pests via the native natural enemies conserved on their farm, however, they did learn a great deal about scouting and the identification of native natural enemies. In year two we also determined that we would need t make more frequent visits to our grower cooperators farms to help them to quantify and qualify data. Observation visits were made to each farm to check in on scouting procedures and overall study success. Weekly communication via email or phone continued throughout the growing season. Scouting reports were submitted by the growers to the HTREF to evaluate need for releases weekly. At both farms in year two, the insect scouting was assigned to student interns and was not undertaken by the farm owners. The data the HTREF received was typically inadequate suggesting the importance of growers in committing time and resources to pest management through bio-control.
In 2004, the objective of conducting practical research to assist high tunnel producers in implementing alternatives to the use of chemical insecticides for insect control in high tunnels progressed. An important component of our project was initiated in 2004 by distributing a survey at several workshops throughout the Mid Atlantic Fruit and Vegetable Conference High Tunnel Production session as well as at the PASA annual meeting in February 2004. At the Mid Atlantic Fruit and Vegetable Conference High Tunnel Production session, approximately 60 growers were in attendance, while at the PASA seminar, approximately 30 growers were in attendance. Of these approximate 90 attendants, survey’s were distributed and 40 survey were returned for analysis. During each of these sessions, Lisa White presented an overview of the SARE project research as well as provided attendee’s with a detailed account of the many facets of biological pest management including the identification of key pests and the most salient natural enemies used to control them. In 2005, Dr. Mike Orzolek, presented the SARE project research findings at the American Society of Plasticulture (ASP) annual meeting in Charleston, SC. In each presentation, an emphasis was placed not only upon the importation and release of natural enemies for pest management but also the conservation and encouragement of native populations of beneficial insects in high tunnel environments.
2) Participation at High Tunnel Field Days and Extension Training Events.
In 2002, a field day and an extension in-service day were conducted at the High Tunnel Research and Education Facility at Rock Springs, PA. The Spring Workshop was held on April 27, 2002
which 28 people attended including growers, researchers and extension personnel from PA, VA, NJ and MA. The Summer Field Day was held on July 19, 2002 cosponsored with the Pennsylvania Association for Sustainable Agriculture (PASA) which 60 people attended including growers from PA, VA, WVA and NY. At Ag Progress Days held on August 22-24, 2002 at the Ag Progress Day site, Rock Springs, PA, tours of the High Tunnel Research & Education Facility were conducted every day with special emphasis on IPM and the SARE project. A total of 550 people toured the high tunnel facility.
In 2003, Extension-In service training events were conducted which highlighted our BioControl project. Sessions were devoted at each event to detail the research we were conducting on site and also provide a forum for interested growers to ask questions and experienced growers to share knowledge related to the use of BioControls in their insect management program. On July 22, 8 representatives from the Pennsylvania Association for Sustainable Agriculture and the Penns Valley Area High School, Milheim, PA toured the high tunnels with a discussion on the benefits of using a BioControl program for insect control in high tunnels. There were 52 extension educators attending the two Penn State High Tunnel workshops held at Rock Springs. Two presentations on the use of biocontrols for insect control in high tunnels were made in February at the PASA Conference in University Park, PA and at Mid-Atlantic Fruit and Vegetable Conference, Hershey, PA.
In 2004, one High Tunnel Grower Workshop and one High Tunnel Workshop were conducted in the state. The one High Tunnel Grower Workshop was conducted at the the High Tunnel Research and Education Facility at Rock Springs, PA on September 13, 2004. Twenty growers attended this meeting emphasizing use of BioControls for insect control in high tunnels. The second High Tunnel Workshop was conducted at the Lehigh County Extension Office, Allentown, PA on September 28, 2004. Fourty growers attended this meeting emphasizing use of BioControls for insect control in high tunnels. At Ag Progress Days held on August 17-19, 2004 at the Ag Progress Day site, Rock Springs, PA, tours of the High Tunnel Research & Education Facility were conducted every day with special emphasis on IPM and the SARE project. A total of 335 people toured the high tunnel facility.
3) Grower survey to determine adoption of the use of BioControls in high tunnels for insect control.
The initial grower survey was to be developed and distributed in 2002, the first year of the SARE project. Because of a reduction in funding received from SARE coupled with a reduction in total funding available for field research in general and high tunnel production/management specifically and limited staff time, the survey work was postponed until 2004. In 2004, 90 active growers were surveyed at two state wide conferences, The Mid-Atlantic Fruit and Vegetable Conference held at the Hershey Lodge and Convention Center, Hershey, PA and the Pennsylvania Association of Sustainable Agriculture Annual Conference held at the Penn Stater Conference Center, State Collge, PA. Of the 90 growers surveyed, 44% of the surveys were returned related to the use of BioControls for insect management in high tunnels. Ninety percent of those growers who responded said they currently use or plan to use BioControl organisms for the control of insect pests in their high tunnel operations. Additionally, approximately 30 growers per year during the 3 year project who were planning to construct a high tunnel made a personal visit to the High Tunnel Research and Education Facility at Rock Springs. Of these 90 individuals, 60 have constructed a high tunnel and 50% of those growers that constructed a high tunnel have implemented an insect control program with the use of BioControls based on the information developed during the 3 year SARE project here at Penn State. Finally, throughout the 3 years of this project, we estimate that we have introduced the concept and practice of biological pest management to 750 producers in the Northeast/Mid-Atlantic regions, most (80%) of whom are currently producing in or are considering production in high tunnels.
Six 17’ x 36’ high tunnels were used in this project. Of the six, three were designated as release high tunnels and the other three served as controls where no releases of beneficial insects were made. There was no attempt made to exclude native predators from establishing themselves in the control tunnels. In each tunnel there were 4 rows of plants, and variety varied by year. All crops planted were either pepper, eggplant or tomato, the most widely grown high tunnel crops in our state. Varieties evaluated over the three year period included:
2002: Eggplant: Neon, Snowy, #226, Pepper: Labrador, Valencia, Ace
2003: Eggplant: Nadia, Neon, Tomato: Red Agate, Sun Gold, Sun Cherry, New Girl, Red Grape, Amish Paste, Big Beef, Mt. Spring, Pepper: Ace, Gourmet, Fat N Sassy, Jimmy Nardello
2004:Eggplant: Orient Charm, Louisiana Long Green, Neon, Black Bell
Tomato: Red Grape, Azafran, Sioux, Mt. Spring, Sun Gold, Sun Cherry, Pepper: Fat N Sassy, Gourmet, Labrador, Islander, Ace
Plants were maintained in a 30’ long by 18″ wide bed with a 1.0 inch thick compost mulch applied pre- plant in year one and plastic mulch in years two and three. Fertigation was supplied as the crop required. Plant spacing was 16″ in the row for all crops. In year three, a field plot was added to help observe predator and pest interactions outside of the high tunnel environment.
Materials used included scouting data entry sheets created by the project coordinator, hand len’s for accurate identification of insects, and yellow sticky cards as well as the beneficial insects purchased for release.
From 2002-2004, scouting was conducted weekly in each of the high tunnels. Each year, new methods were refined to help decrease the time spent scouting and to increase accuracy and reliability as detailed below. Scouting was conducted by randomly choosing two plants per variety to flag for the season; there were typically two varieties per row (or where only one variety was used per row, four plants of the same variety were flagged). In total, sixteen plants per high tunnel were scouted each week and variety and species composition changed yearly.
Aphid and whitefly were counted in total on each plant for the first half of the growing season (April-June). This was easy enough when the plants were small, however, it quickly became excessively time consuming so that the following system was created:
Pests were given a scale per plant: 1: 1-25 pests, 2: 25-100 pests, 3: 100-200 pests, 4: 200-300 pests, and 5: 400+ pests. Each pest was given its own value, for example the aphid scale for one bell pepper plant could have been a value of 3, while the whitefly scale value could have been a 1. Those scouting inspected the plant thoroughly but efficiently to accurately assign a scaled value. Pest populations were also noted according to their location on the plant (H=High, M=Medium, L=Low) as well as location within the high tunnel (Front, Middle, Back).
Total predator numbers were counted in various life cycle stages (egg, nymph, pupae, adult) and never assigned a scale value. The entire plant was inspected carefully but efficiently to observe the presence of predatory insects. In 2002, we were primarily working with the ladybird beetle and green lacewing to achieve control of aphids, and these species in particular are rather easy to identify on the plant.
2003: Same procedure as 2002
In 2004, improvements were made regarding the scouting procedure. As with the previous year, the plant as a whole was given a scale for the target pests (aphid and whitefly), however, per each plant; 9 leaves (3 from the lower, 3 from the middle and 3 from the top part of the plnat) were randomly selected during each scouting event whereby the total numbers of pests and predators were counted. This enabled us to gain a much better picture of spider mite infestation so that plant damage (not individual mites!) was either present or absent. This system also allowed us to obtain better records of thrips presence (since they are more difficult to find than aphid and whitefly). Also new in 2004 was the Qualitative Plant Scale index. Each plant was given a scale from 1-5 in regards to the following criteria: disease symptoms, nutrient deficiency/toxicity symptoms, irrigation effectiveness etc. A value of 1 indicated the plants were in very poor health and a value of 5 indicated excellent plant health. This scale allowed us to identify the presence of virus symptoms on plants.
Predators were scouted in the same manner as in 2002 and 2003, however, the variety of beneficial insects used in our release events was also expanded in part to help guard against expanding populations of spider mite that were not observed in the previous two years.
In 2004, companion plants were added into each of the six high tunnels to help encourage not only the successful establishment and reproduction of insects released in the release high tunnels but also to observe the enticement of native natural enemies into the control high tunnels where no releases were made.
One of the high tunnels that served as a control had aphid populations that were significantly higher than the aphid population in the other control high tunnel; in fact, the aphid population exceeded the economic threshold level almost immediately in the early part of the growing season. Insecticidal soap was sprayed at the same time intervals as ladybird beetles were released in the treatment tunnels, however the soaps provided only temporary knock downs for the aphid population and did not offer significant control. After releases of the ladybird beetles were made in the three treatment high tunnels, the ladybird beetles moved into the control high tunnel with the injuriously high aphid populations and assisted in controlling aphids. Whitefly populations peaked and then declined, all the while staying below the economic threshold level, however, by the end of the season, populations began to rise again, however, no specific control measures were required due to pending frost and crop removal.
Release Dates (each with corresponding insecticidal soap application @ 2oz/gal):
Ladybird Beetles 1 qt. per high tunnel ($12/qt)
In 2002, pest populations stayed well under the economic threshold levels with few additional pest control measures required in the high tunnels. In July, after three ladybird beetle releases were made beetle populations increased although little reproduction was occurring as seen by the relatively low population of nymphs. Towards the end of the growing season, green lacewing egg’s were observed within the tunnel although no adults were sighted during routine scouting during the day (which is to be expected).
In 2003, aphid populations were high in the early part of the growing season (May, June), with releases of aphid parasitizing wasps, aphid populations were controlled very effectively by July and steady declines were observed throughout the rest of the growing season. Whitefly populations remained low while the aphid populations were rising, however, by the middle of the growing season, whitefly populations were on the rise and peaked during July and August. Releases of whitefly parasitizing wasps were not effective in controlling whitefly populations because they were not made earlier in the season when populations were still low. Encarsia must be released on a preventative schedule, rather than waiting until populations of whitefly warrant real concern. In year two, we also made the decision to include a greater variety of natural enemies for more targeted control of our pests. Instead of using only ladybird beetles and green lacewings as originally proposed, this year we also released aphid and whitefly parasitoids. Including these parasitoid insects was an important decision and we believe greatly helped to control pests much better than with the original predatory species alone.
Ladybird Beetles: May 9 (1 cup per tunnel)
Green Lacewings: May 9 (1000 eggs per tunnel)
Encarsia formosa: May 16 (3 Encarsia cards per tunnel), May 23 (3 cards), Aug 10 (3
Aphidius colemani: May 23 (1/3 container per tunnel)
Neoseiulus cucumeris: May 16 (15 bags per tunnels)
Total Cost: $221 (not including shipping; approximately an additional $75)
In 2003, pest populations were higher than in 2002 but generally stayed under the economic threshold levels with some additional pest control measures (insecticidal soap and horticultural oil applications) required in the control high tunnels. It was observed that not only were the predator releases visible in the treatment high tunnels, but also native predators and parasites were also observed parasitizing insect pests on tomato, pepper and eggplant. It was also observed that ladybird beetles and green lacewings released in the bio-control treatment high tunnels migrated to the other high tunnels within the complex and afforded effective aphid control in those high tunnels.
In 2004, aphids were managed very effectively with parasitizing wasps. In 2004, native ladybird beetle populations were very high both within the high tunnels as well as in field crops and subsequently provided control for aphids. In 2004, whitefly was also managed effectively with preventive releases of parasitizing wasps (Encarsia and Eretmocerus).
Spider mite presented the most significant problem encountered at the HTREF in 2004. This was somewhat unusual considering the rather cool and wet summer, however, even when cool and wet outside, it can be warmer and dry in the high tunnel. While aphid and whitefly populations were managed very effectively, more releases of spider mite predators would have been helpful early on in maintaining a population below the economic injury Level
Encarsia formosa: May 14 (3 cards per tunnel), May 26 (3 cards), June 11 (4 cards), July
9 (6 cards), July 23 (6 cards), August 7 (6 cards), August 27 (4 cards)
Aphidius colemani mix: May 20 (1/3 container per tunnel)
N. californicus/M. longipes (Benemite): May 20 (1/8 bottle per tunnel), August 7 (1,000
mites per tunnel)
Green Lacewings: May 20 (500 eggs per tunnel)
N. cucumeris: May 26 (10 bags per tunnel)
Eretmocerus: May 26 (1/3 container per tunnel)
Ladybird Beetle: June 4 (1/3 pint per tunnel)
By mid July 2004, two research high tunnels planted with Mt. Spring tomato were diagnosed with Tobacco Mosaic Virus, Cucumber Mosaic Virus and Tomato Spotted Wilt Virus; the study in these structures was terminated and the plants disposed of immediately, leaving the study with four high tunnels planted with mixed solanaceous crop.
Similarly, years 1 and 2 of the project caused us to recognize the importance of not only quantitative data and analysis but also qualitative and empirical data. In year 3, data was collected as in the first two years of the study but a more qualitative and characterized analysis was also made of each high tunnel each week to give an overall and more subjective description of the state of pest management in each high tunnel. This helped us to make some notes of pests or predators that were encountered in the high tunnel but were not located on the flagged (scouted) plants. It also allowed those scouting to get a ‘feel’ for the ‘state of health’ of the high tunnel and make weekly observations of other non- target pests, natural enemies, disease or nutrient deficiencies or toxicities, etc… This more ‘holistic’ characterization did not take the place of the quantitative data that was also collected for the purposes of the study.
Despite effective management of target pests, spider mite, thrips and virus related problems caused a decline in crops and efforts in subsequent years at the HTREF will need to be evaluated to control these pests and viruses.
The outreach involved in this project was significant and provided our strongest contribution to our stakeholders. In conclusion, our research was presented at three field days and five Extension-in service training events, two Ag-Progress Days tours and three professional meetings. We published a High Tunnel Production Manual in 2003 with a detailed chapter on IPM and bio-control and in conclusion will release a specific publication detailing the research conducted over the three years of this project.
Additional Project Outcomes
Impacts of Results/Outcomes
In 2002, our research produced positive results and successful use of bio-controls managing our key pests of aphid and whitefly. We determined that releasing ladybird beetles was more effective at maintaining low pest populations, but also more economical than making repeated spray applications of insecticidal soap. This gave us some confidence that the use of chemical pesticides may be decreased and or eliminated by growers who choose to implement bio-control practices in their high tunnels by using ladybird beetles to manage aphids.
In 2003, we again achieved success using biological controls in our study and our results were quantified in a series of graphs that show our target pest populations staying well below the Economic Injury Level (EIL) for the specific crop, especially in the high tunnels where releases were made. In the other high tunnels where releases were not made, sufficient pest control was also achieved with decreased use of ‘soft’ pesticides. Few crops, including those not involved in the study required applications of insecticidal soap or oil. Released natural enemies made their expected impact on pest populations within the high tunnels that they were released within, and native predators and parasitoids were also noted to have played an important role in pest control as well (such as the aphid midge and Aphidoletes sp.) Similarly, species released in the study tunnels migrated to other tunnels after achieving effective control in the study high tunnels. As with 2002, detailed economic records were kept and the economics of biological pest management were evaluated (see below). Also in year two, new methods for scouting were devised which we believe will be much more practical and useful for growers.
In 2004, by surveying at PASA and PVGA, we were able to better prepare for the
the compilation of our high tunnel biological pest management publication. We provided direct, hands on training at five separate events in this year where our stakeholders, from growers to educators, and even children on school tours were introduced to the theory and application of biological pest management in the high tunnel environment. Many of the educators expressed a strong interest in this topic and requested additional hands on training in the high tunnels. A tour of extension agents and educators spent the morning scouting the high tunnels with our staff. This served as an excellent forum for them to become more comfortable identifying native natural enemies. All participants who had an interest were exposed to a variety of beneficial insects in various life stages, this developed into over an hour of intense insect scouting at the PASA sponsored field day at Quiet Creek Herb Farm. This direct learning experience proved to be invaluable as many of our stakeholders had heard of such insects like the green lacewing or parasitoid wasps but had never had the opportunity to view them up close and in person. Also in 2003, we continued our work with our grower cooperators. Lisa White, the project manager along with trained HTREF staff made monthly visits to each cooperator farm. Detailed training was initiated early each spring and interns on both farms conducted much of the subsequent scouting each week. Releases were made on each farm and control of our target pests, aphid and whitefly was achieved. Moreover, in an effort to help to attract native natural enemies, companion plants were introduced into the six high tunnels used in this study at the HTREF. Observational results suggested that inter planting flowering pollen and nectar bearing species with our solanaceous crops did in fact contribute to the increase of native natural enemies in the high tunnel environment such as the ladybird beetle and green lacewing.
Each year, detailed records of the time spent scouting, as well as the cost of each release of beneficial insects were kept. In 2002, we estimated that biological pest management for each of the three high tunnels where releases were made cost $13.50, where as chemical control in the three control tunnels cost $19.00. Both of these figures were quite economical because pest populations did not require significant intervention. In 2003, our costs increased to $51.00 per each of the three release high tunnels. Chemical control cost also increased as more soap applications were made and thus rose to $25 per high tunnel. This increase included the aphid and whitefly parasitoid releases as well as the ladybird and green lacewing releases. In 2004, pest management costs increased again to $115.00 per each of the three high tunnels and this increase included bio-control agents for spider-mites and thrips management as well as preventive releases of whitefly parasitoids. No pesticide applications were made in any of the research high tunnels in 2004 to help compare the effect of bio-control versus no pest control and so a chemical cost can not be evaluated. Although these figures represent the cost of these releases made in each of the three release high tunnels, they do not account for the control that these insects provided upon migration to other high tunnels, which we noted was significant. Thus, it is within reason to assume that these economic figures are actually high and if the total cost is further divided by a greater number of high tunnels, the economics look even better for bio-control.
In year one, scouting required about forty hours a week, which was very excessive. Upon revising the scouting procedure for greater efficiency, scouting consumed about twenty to twenty five hours per week through the six high tunnels. It is also worth nothing, that a grower would not need to keep as accurate and detailed records as was required for our research project and could this spend only an hour or two a week scouting rather than our fifteen.
Through our Extension and outreach, hundreds of citizens, growers and technical advisors were educated about using biological pest management. Surveys conducted at PASA and PVGA revealed that most of our forty respondents will consider using bio-control practices if they do not already use bio-control practices on their farm.
Areas needing additional study
Pest management on each farm received mixed reviews as various new and challenging situations arose. Plant viruses posed significant threats to crops at the HTREF as well as at Cedar Meadow farm on tomato crops in 2004. This served as a learning experience for us all. Managing for viruses requires different strategies than managing solely for pest damage below the economic injury level as vector species such as thrips (and aphid and whitefly) can transmit viruses throughout a crop even at low densities. Moreover, while aphid and whitefly were very successfully controlled at all three research sites, spider mite presented a much more significant problem this year that required the use of new natural enemies and tactics for control. Unfortunately, we were not able to get ahead of the learning curve for managing spider mite biologically this year, but will be much better prepared next year. Moreover, despite great enthusiasm and interest by growers, they are reluctant to spend the time it takes learning to properly identify insects, even when provided with resources and training. How to manage this drain on time and energy is a problem that must be addressed if growers are to successfully adopt bio-control practices. Another potential area for further study in entomology is to evaluate which insects, pest and beneficial are able to over-winter in the high tunnel environment and evaluate management tactics to discourage pests and encourage beneficial insects.