Jump to main content.

Pesticide Exposure Reduction in Pennsylvania Conifer Plantations using an IPM Approach for White Pine Weevil, Pissodes strobi (Peck), Management

David Bingaman
PA Dept of Agriculture, Bureau of Plant Industry
2301 N. Cameron Street, Harrisburg, PA 17110
717-772-5208 (phone), 717-783-3275 (fax)
dbingaman@state.pa.us

Purpose Statement

An Integrated Pest Management strategy to manage White Pine Weevil in conifer plantations will reduce organophosphate pesticide applications thus preserving natural enemies, protecting non-target species and providing a safe working environment for employees.

Project Duration: 2 years

Funding Request
Budget Category Funding Requested Matching Non-Federal Funds Matching
Federal Funds
First Year Funding
$19,600
$11,437
0
Second Year Funding
$20,600
0
0
Total Funding
$40,200
$11,437
0

Executive Summary

A major source of concern to conifer growers (Christmas trees and nursery production) is damage cause by White Pine Weevil, (WPW), (Pissodes strobi (Peck)). Current practices to control this pest consist mainly of large quantities of traditional pesticides. Unfortunately, few compounds are labeled for WPW control. With limited classes for rotation, the potential of insect resistance to these few compounds is great with marginal control.

Many conifer growers are aware of IPM strategies but lack the training to implement techniques specific to better control of WPW. This missing cornerstone contributes to untargeted applications of pesticides, disrupts the ecological balance of natural enemies, increases environmental contamination, and creates unnecessary exposure for workers. Many producers are faced with issues concerning homes being built near tree plantations. The project requests funds to develop and implement IPM strategies to reduce the risks associated with unnecessary pesticide applications.

The objectives of the project will be: (1) conduct IPM training seminars for better understanding of WPW life cycle and IPM techniques such as trapping, monitoring, growing degree day (GDD) accumulation and record keeping, (2) integrate soft pesticides into spray regime to replace traditional classes of insecticides, preserving the natural enemy complex, and (3) reduce pesticide use 50% by end of project period.

The development and implementation of these objectives over a two-year period will reduce the risk of worker exposure to pesticides, minimize the impact of pesticides in the environment and provide conifer growers with alternatives for managing insecticide resistant pests. Dissemination of project results will be widespread with cooperation of the Penn State Christmas tree website and the Penn State/Dept of Agriculture IPM website.

Objectives

  1. Conduct IPM training seminars for better understanding of WPW life cycle and IPM techniques such as trapping, monitoring, GDD accumulation and record keeping.
  2. Integrate soft pesticides into spray regime to replace traditional classes of insecticides, preserving the natural enemy complex.
  3. Reduce pesticide use 50% by end of project period.

Rationale

Objective No. 1 - Conduct IPM training seminars for better understanding of WPW life cycle and IPM techniques such as trapping, monitoring, GDD accumulation and record keeping.

A substantial amount of insecticides requiring multiple applications are necessary to control a devastating pest of conifers, the White Pine Weevil, Pissodes strobi, (Peck) (Coleoptera: Curculionidae). These multiple applications using a limited number of insecticide classes result in the development of insecticide resistant pests. The United States Environmental Protection Agency, under the Food Quality Protection Act of 1996 (FQPA), has sought to reduce the risk associated with organophosphate pesticide use through tighter restrictions and product cancellations. The conifer industry is very reliant on organophosphates and thus alternative IPM strategies are needed to reduce their reliance on these compounds.

WPW is a native insect attacking at least 20 different tree species such as Eastern white pine, Colorado blue spruce, Norway spruce and Douglas fir. Eastern white pine (Pinus strobus L.), a valuable species grown for Christmas tree production and landscape plantings in Pennsylvania, is the most suitable host for immature development of this pest. This pest is a major source of concern for Pennsylvania conifer growers since the damage caused by this pest results in dieback of the central leader and surrounding branches making the tree unsuitable for sale. This results in a considerable loss of profit to the nursery operation. Because they lack the basic understanding of the pest life cycle and biology, growers tend to make excessive and ineffective pesticide applications which allow the WPW population to persist and increase year to year. Since most growers rely on local chemical distributors for pest control information, IPM strategies are often overlooked. More information is required to make targeted applications at the most susceptible life stages. Through the use of IPM techniques, such as crop scouting, pest trapping, and observation of growing degree days, growers can greatly reduce their reliance on conventional pesticides, thereby prolonging the effectiveness of existing compounds.

By implementing a scouting and trapping program in conjunction with a GDD monitoring system, growers will be aware of peak adult activity and thus may synchronize insecticide applications that target the most susceptible life stage. Conifer growers feel that they are more likely to learn and implement IPM methods by working closely with an IPM trained professional who can demonstrate and advise them on the most effective methods. The PDA greenhouse IPM program (EPA, Implementing Greenhouse IPM in Southwestern PA and Greenhouse IPM for the Amish and Mennonite Community of Lancaster County) has shown that working with growers on a one to one basis increases their adoption of IPM strategies.

Objective No. 2 - Integrate soft pesticides into spray regimes to replace traditional classes of insecticides, preserving the natural enemy complex.

There are several natural enemies of WPW; however most are eliminated with applications of traditional classes of broad spectrum insecticides. Most insecticides for control of WPW are highly toxic and labeled as restricted use. With the further implementation of the FQPA, choices of traditional classes will become more limited. Over-applications of restricted use pesticides can be injurious to humans, animals, and to the natural complex of beneficial organisms that keep pests in balance. However, there are chemical compounds that minimize negative effects on indigenous beneficial insects. Through this program, growers will learn about these compounds and how they can be used to minimize natural enemy mortality. This approach will prevent the increase of secondary pest populations and will provide the grower with an IPM tool to minimize WPW tolerance to insecticides.

Objective No. 3 - Reduce pesticide use by 50% by end of project period.

Because of the labor intensive nature of the spray procedures, workers face a high level of exposure to toxic insecticides. The benefits of this program include reducing worker exposure to pesticide residues, as well as minimizing groundwater and spray drift from ground and aerial pesticide applications. In addition to reducing worker safety risks, this pesticide reduction is also beneficial to the developing housing community that is encroaching on conifer plantations. An added economic benefit to the grower is saving money through reduced chemical costs and reduced fuel consumption for spray application equipment.

The effects of an IPM program for conifer production would greatly impact the four thousand acres of conifer production in Schuylkill County, which include some of the largest plantations in the state. For example, with approximately 24 pounds of active ingredient per acre of production, a 50% reduction of pesticide use would amount to substantial savings in pesticide costs and a reduction in pesticide loading. This decrease will protect naturally occurring beneficial species in the environment and reduce pesticide exposure for employees and the surrounding community.

Implementing an IPM program with the largest and most respected growers in the region will result in widespread adoption by smaller growers throughout Northeastern PA. Educational presentations of the data collected will be available for statewide use and for creating training programs for other geographic regions of the state. The results will help extension agents provide new and interesting information in pesticide education training sessions. The data will also be available on the 1-800-PENNIPM hotline, so that growers can access real time data for use in planning pest control methods. Additionally, information will be updated weekly on the Penn State Christmas tree website and links will be added to the PAIPM website.

Approach and Methods

Objective No. 1 - Conduct IPM training seminars for better understanding of WPW life cycle and IPM techniques such as trapping, monitoring, GDD accumulation and record keeping.

Southeastern PA (Schuylkill County) has a concentration of conifer growers with approximately 4,000 acres in production. Three large growers have interest in developing an IPM program for their operations that consist of both cut Christmas tree and balled and burlap (B&B) production. These growers will be trained on a weekly basis by an IPM specialist, Linda Signarovitz, who has had 35 years of experience working in the nursery industry. Growers are expected to accompany the IPM specialist to insure that they acquire the scouting skills needed to implement and sustain an IPM program. Through this routine contact, growers will be taught insect identification, trapping techniques, tree inspection for adult weevil activity and record keeping of insect data as well as GDD totals.

Trapping techniques will consist of setting pyramidal, Tedder traps that are baited with ethanol and turpentine and spaced strategically throughout fields with susceptible tree species.

Monitoring will include checking traps and recording data for adult weevil presence as well as visual inspection of tree leaders. Digital weather stations recording maximum and minimum temperatures will be placed in each conifer plantation for accurate GDD accumulation. Growers will be expected to record data and maintain records for future reference.

The IPM consultant will work cooperatively with Penn State extension educators and PDA professionals to deliver educational programs to growers at regional and statewide meetings. The focus of these meetings will be training on identification of WPW life stages as well as the environmental factors that influence adult emergence and subsequent oviposition.

Objective No.2 and No. 3 - Integrate soft pesticides into spray regimes to replace traditional classes of insecticides, preserving the natural complex of enemies and reduce pesticide use 50% by end of the project.

Through year two of the program, PDA and Penn State professionals will be able to recommend soft pesticides to replace the restricted use compounds that growers currently use. Our hope is that with the anticipated success of year one of the program, growers perception of the risks associated with using IPM strategies will be minimized. This new understanding coupled with their continued education of the negative affects of using synthetic broad spectrum chemicals should encourage their use of compounds that preserve natural enemies as well as lowering risks to workers. The implementation of a scouting program provides the information needed to use target specific pesticides.

As growers become more educated and sprays more specifically targeted, control will be achieved with fewer sprays resulting in a decrease of active ingredient per acre. We anticipate a spray reduction of 50% in the second year and potentially a larger reduction in future years.

Background Information

The ‘Green Industry’ in Pennsylvania comprises over 25% of the state’s total agriculture sales. As a part of the ‘green industry,’ conifer production in PA is ranked fifth in the nation, with a total of $41,763,000 in conifer and Christmas tree sales for 2003 (USDA, 2003). This commodity makes up a substantial part of the agricultural economy that is so important to the state. In Schuylkill County, one of the leaders in the state for conifer production, there are approximately 4,000 acres of conifer plantations. White pine weevil is one of the major pests of these trees, and causes major financial injury to nurseries across the county and state each year.

White Pine Weevil or Pissodes strobi (Peck), a member of the Curculionidae family, attacks coniferous evergreen trees such as eastern white pine (Pinus strobes), Colorado spruce (Picea pungens), Norway spruce (P. abies) and Douglas fir (Pseudotsuga menziesii) (Lehman, 1993). A native species to Pennsylvania forests, it prefers to reside in the nursery setting, where it has access to large fields planted with single species of trees outside of the shade canopy of the forest setting. These conditions are highly favorable for WPW population explosions (Alfaro, 1994).

In the life cycle of WPW, one generation is produced in a year. In the early spring, adult weevils, which have over-wintered in the duff of host trees, will fly or crawl to the leaders of surrounding host trees. It is in these leaders where the damage occurs. The WPW begin feeding and mating on the leaders, and shortly after, will commence with oviposition. The females will deposit eggs (1-5) in small feeding holes along the leader, and will then plug the holes with fecal matter and tree resin. Each female may lay 100 - 200 eggs. The eggs hatch to form larvae, which feed on the vascular tissue in the shoot. This internal damage to the tissue is what causes the leader to die, appearing to droop in the form of a shepherd’s crook, which is the distinguishing deformity of WPW damage. Starting from late July through August, adult weevils emerge from the shoot and will feed on the leader until early fall when they will move into the duff to hibernate for the winter. (Hamid et al, 1995)

Without knowing exactly when adult weevils emerge in the spring, growers can miss this vulnerable life stage and the appropriate time for pesticide applications. One of the current practices is tracking the GDD, or a range of days above a specific base temperature. In the case of WPW, the base temperature is 50ºF. After this base temperature has been reached, emergence can take place with in the range of 1-58 GDD. Detecting the adult emergence involves setting traps for the weevils. Pyramidal traps, called Tedders traps may be spaced throughout susceptible trees, next to areas of past weevil infestation (Gardosik and Lehman, 2005). These traps simulate the shape and height of the trees and draw the weevils to the apical cage with a bait of ethanol and turpentine. By beginning to monitor temperatures and setting traps in early spring, growers will be able to monitor for evidence of adult weevils in the trap. When the adults are in the traps, they will also be on the trees and this is the time for growers to begin treating the crop with targeted sprays. After the spray stages, growers may also implement mechanical control techniques. By pruning the infested tree leaders before the adults emerge, growers can reduce the weevil population (Hamid et al, 1995).

Growers rely heavily on pesticides to control the WPW. Thus far, the pesticides used to control this pest fall into the ‘restricted use’ category, with the largest amount in the organophosphate class (Gardosik, 2005). Because growers are only rotating insecticide sprays in this class, it is likely that the WPW population will develop resistance to these compounds. Another problem with this class of pesticides is that they are broad-spectrum in nature and kill non-target insects, including natural predators and parasites. Some natural enemies include Eurytoma pissodis Gir. and Dolichotomitus terabrans nubilipennis (Viereck), which are hymenopteran parasites, and Lonchaea cortis (Taylor), a dipteran predator (Hamid et al, 1995). With reduction of broad-spectrum insecticides, these insects may aid in the control of WPW.

Resources

Penn State University and PA Department of Agriculture

Penn State extension specialists and county educators will assist in educational aspects of the project by working directly with growers in the field and organizing and conducting grower seminars at a regional and statewide level. Additionally, they will assist in developing the IPM procedures and evaluate the results of the project as a team member. An existing Penn State Christmas Tree website is maintained by Paul Heller, Professor of Entomology, in cooperation with the PDA. We will incorporate the results into the Penn State Christmas tree short course, so that additional producers will be exposed to the concepts. PDA personnel (nursery inspectors, pesticide education specialists, and entomologists) will play a major supporting role in the implementation of the program. Laboratory facilities are available at both institutions for diagnostic work.

Measures and Outcomes

The success of this project will be measured through the assessment of pesticide records from previous years and damage estimates in susceptible tree species. The pounds of active ingredient used in previous years will be compared to years one and two of the project to determine the percent decrease.

A statewide survey will be conducted to determine the impact of the education aspect of this project. We hope to determine the impact of regional and statewide training sessions on the control practices of growers. Survey results will be used to explore new grant opportunities in the development of biological control methods for WPW.

Outreach

As the anticipated success of this project is observed by conifer producers across the state, we expect widespread adoption of these IPM techniques by growers not involved in the project. The use of such data by extension agents provides new and interesting updates for pesticide education training sessions held throughout the fall and winter seasons in the state and regionally. Pest management data is available using the 1-800-PENNIPM hotline so that growers can access real time data for use in planning pest control methods. Additionally, information will be updated weekly on the Penn State Christmas tree website and links will be added to the PAIPM website. Additionally, information will presented at trade shows, conferences and fairs that serve the nursery industry.

Sustainability

By training the conifer producer on a one to one approach, education will be sustained in the operation and operating with a more ecological management. A logical approach is to expand the project and work with other county agents. Additionally, publication in national trade journals and grower publications will disseminate information nationwide.

Literature Cited

Alfaro, R. I. 1994. The White Pine Weevil in British Columbia: Biology and Damage, pp. 7-22. Proceedings of a Symposium, 1994. Canada-British Columbia Partnership Agreement on Forest Resource Development.

Cornell University. White Pine Weevil. Christmas Tree IPM Pest Web Page. http://ppathw3.cals.cornell.edu/Trees/WPWeevil.html . (08/01/05)

Gardosik, S. 2005. Insecticides and Miticides for Christmas Tree Pests. Pennsylvania Department of Agriculture.

Gardosik, S. and R. Lehman. 2005. White Pine Weevil Detection Traps. Pennsylvania Department of Agriculture. http://ctrees.cas.psu.edu/pdfs/whitepinewvtraps.pdf . (07/27/05)

Hall, P. M. 1994. Ministry of Forests Perspectives on Spruce Reforestation in British Columbia, pp. 1-6. Proceedings of a Symposium 1994. Canada-British Columbia Partnership Agreement on Forest Resource Development.

Hamid, A., T. M. ODell, and S. Katovich. White Pine Weevil. Forest Insect and Disease Leaflet 21. U. S. Department of Agriculture, Forest Service. http://na.fs.fed.us/spfo/pubs/fidls/wp_weevil/weevil.htm . (06/06/05)

Lehman, R. D. 1993. White Pine Weevil, Pissodes strobi (Peck). Regulatory Horticulture. Entomology Circular 154.

MacConnell, C. 2004. Integrated Pest Management for the Raspberry Beetle, Byturus unicolor (Say), Using Life Stage Prediction and Cultural Management in Red Raspberry Production- Final Report. Pesticide Environmental Stewardship Program. http://www.epa.gov/oppbppd1/pesp/regional_grants/2004/r10-2004.htm . (07/08/2005)

O’Farrill-Nieves, Ph. D., H. 2004. Development of a Landscape IPM Program in Puerto Rico- Final Report. Pesticide Environmental Stewardship Program. http://www.epa.gov/oppbppd1/pesp/regional_grants/2004/r2-2004.htm . (07/08/2005)

Tedders, W. L. and B. W. Wood. 1994. A New Technique for Monitoring Pecan Weevil Emergence (Coleoptera: Curculionidae). J. Entomomol. Sci. 29: 18-30.

U. S. Department of Agriculture, National Agricultural Statistics Service. 2004. Nursery Crops 2003 Summary.

Timetable

January 2006 – March 2006

April – August 2006

September – December 2006

January 2007 – December 2007

Major Participants

Participating Growers

These growers have agreed to participate in this IPM program and conduct the tasks that are required to complete project objectives.

Local Navigation

Jump to main content.