Enhancement, Implementation - Evaluation of Biologically Based Pest Management Tactic for Three Key Pests in Production Nurseries

2005 Annual Report for LNE02-167

Project Type: Research and Education
Funds awarded in 2002: $138,636.00
Projected End Date: 12/31/2006
Matching Non-Federal Funds: $32,651.00
Region: Northeast
State: Maryland
Project Leader:
Dr. Paula Shrewsbury
University of Maryland

Enhancement, Implementation - Evaluation of Biologically Based Pest Management Tactic for Three Key Pests in Production Nurseries


The importance and production of ornamental plants has increased dramatically over the past decade. For example, production of nursery and greenhouse crops is first among all crops in 10 of the 12 states in the Northeast region. Pest management is a major component and challenge in ornamental plant production. This industry is heavily dependent on pesticides, which continue to be its primary pest control method (Hudson 1996). Nursery growers and Integrated Pest Management (IPM) scouts are looking for non-chemical pest management alternatives due to societal, environmental, and regulatory (FQPA) pressures. However, growers and scouts are unwilling to take the risks associated with new methods until they have been demonstrated to be economical, practical, and effective. This project aims to address these needs and reflects input solicited from IPM scouts and nursery growers in Maryland.
The 4 phases of the proposed 4 year project are: 1) research to evaluate the efficacy of, and refine techniques for using a biologically based pest management tactic, 2) a demonstration phase to integrate this and other tactics into a biologically based IPM program in commercial nurseries and evaluate their applicability (efficacy, ease of use, and profitability), 3) an education phase to extend results to end users and increase the likelihood of adoption of these biologically based tactics and IPM, and 4) perform an impact assessment to determine and document changes in practice, knowledge, and attitudes of beneficiaries. In addition, a committee of project beneficiaries (IPM scouts, nursery managers, and demonstration cooperators) will be formed from which feedback, in the form of discussions and emails with project investigators, will be solicited at key points in the project to assure the project stays on track.

Objectives/Performance Targets

  1. 1. To refine and evaluate biologically based pest management tactics, habitat manipulations, for their feasibility (effectiveness, ease of use, and profitability) in increasing generalist predator populations, with a concomitant reduction in pest populations (Research).
    2. We predict that 3 of the 4 commercial nurseries and all 3 of the 3 IPM scouts engaged in the demonstration phase of the project will continue to implement biologically based pest management tactics over chemical tactics (Demonstration).
    3. We predict that 100 of the 250 nurseries in Maryland will increase their implementation of biologically based tactics, and that 25 of the 36 participating Extension personnel in the NE region will increase the number of times they train on biologically based control tactics for one year after participating in SARE education programs compared to the previous year (Education and Evaluation).


For 2002, our goal was to develop and evaluate biologically based pest management tactics by conducting an applied research project (Performance Target 1). More specifically we determined: 1) the effect of adding wood mulch to nursery beds with container plants of Cotoneaster dammeri compared to weed cloth beds and 2) the effect of plant / pot position (above ground compared to pot in pot) on arthropod (herbivore, alternative prey, natural enemy) taxa and abundance and herbivore (Hawthorn lace bug and black vine weevil) survival. This goal was accomplished.
In 2003, we identified 3 nursery cooperators. In 2003 and 2004, the demonstration phase of the project was implemented (Performance Target 2). This phase integrated biologically based tactics into commercial nurseries and evaluated their efficacy. The goal was to increase the implementation and adoption of biologically based pest management tactics over chemical tactics (Performance Target 2). In one nursery, during 2003 and 2004, we implemented a program targeting the management of azaleas and their key pest, azalea lace bug. We examined two habitat manipulations (use of wood mulch ground cover, a pot-in-pot planting system). We further examined the impact of these habitat manipulations on ground active compared to foliar feeding pests. In a second nursery, in 2003 and 2004, we examined the use of augmentative releases of predatory mites to manage a key mite pest, southern red mite, on Ilex species. In a third nursery, during 2004, we examined the use of the pot-in-pot planting system and entomopathogenic nematodes to manage black vine weevil.
In 2005, data from all research and demonstration projects was consolidated and analyzed, and preparation of refereed publications began. A Masters of Science thesis was produced.
In 2003, 2004, and 2005, results of the research and demonstration projects were presented to nursery growers at educational programs in MD, other the Northeast region states, and nationally (Performance Target 3).

Impacts and Contributions/Outcomes

As part of the research phase of this project, we evaluated biologically based pest management tactic, habitat manipulations, for their efficacy in increasing generalist predator populations, with a concomitant reduction in pest populations and damage (Performance Target 1). In comparing the taxa and abundance of alternative prey and natural enemies in plant containers between ground cover types (mulch vs. weed cloth beds), and pot position (pot in pot vs. above ground pots) we found no effect of mulch. However, natural enemies were greater in pot-in-pot containers than in above ground containers. Individual predators, such as ants, rove beetles, ground beetles, and spiders, and a parasitoid (Scelionidae) were found to be more abundant within pot-in-pot containers than in containers above ground. Arthropods, such as Collembola that likely serve as alternative prey for predatory insects, were also more common in the pot-in-pot position than the containers above ground.
We found that the mulch and weed cloth treatments rarely differed in their effect on survival of hawthorn lace bug nymphs or the eggs and larvae of black vine weevils. We also found that the pot position had a variable effect on hawthorn lace bug survival. However in all experiments, predation of black vine weevil eggs and larvae was dramatically higher in containers in the pot-in-pot versus above ground planting method.
As part of the demonstration phase of this project, we implemented biologically based pest management tactics in 3 nurseries (Performance Target 2). To date the data indicate that ground cover type and pot position had a significant effect on generalist predator (ground and rove beetles, spiders, and ants) and alternative prey abundance within the plant containers, where abundance was greater in wood mulch compared to weed cloth plots, and greatest in the pot-in-pot than above ground planting method. However, there was no significant effect of ground cover type, but there was a significant effect of planting method on herbivore survival (lower survival in pot-in-pot). Herbivores active in the soil (at the soil line) were significantly more susceptible to predation compared to herbivores on the foliage. This effect was slightly enhanced in pot-in-pot plants but ground cover did not influence this effect. Cost and impact evaluations of this program are underway. Studies also found that black vine weevil larval abundance in herbaceous perennial plants was lower in plants using the pot-in-pot system than above ground; and that entomopathogenic nematode applications reduced weevil larval abundance compared to no treatment control plants. Other studies found that augmentative release of predatory mites to suppress Southern red mite on Ilex spp. was not effective. Further studies are needed to improve the efficacy of this management tactic.
As part of the educational phase of this project, results of the research and demonstration projects were presented at several professional and end-user educational programs throughout the northeast region and nationally in 2003, 2004, and 2005 (approx. 1,900 professionals trained). These included: 7 presentations at Entomological / IPM professional conferences; 10 University seminars; 9 green industry professional association meetings / recertification conferences, 3 Cooperative Extension short courses; and 4 nursery field day held in MD. In 2004, an overview of this project was placed on line at http://shrewsburylab.umd.edu. A summary poster on the effect of habitat manipulations on pest insects and natural enemies on ornamental nurseries was developed and displayed at the Northeast SARE conference in Burlington, Vermont during October 2004.


Stanton Gill

[email protected]
Regional Extension Specialist
University of Maryland Coop. Extension Service
Central MD Research and Education Center
11975 Homewood Road
Ellicott City, MD 21042
Office Phone: 3015969413
Colin Stewart

[email protected]
4700 River Road
Riverdale, MD 20737-1231