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Pennsylvania Christmas Tree Growers Benefit From IPM - September 2005
July 13, 2005
UNIVERSITY PARK, Pa. -- Christmas tree growers in southeastern Pennsylvania are reducing their pesticide use up to 50 percent a year while eliminating a devastating pest, say researchers at Penn State and the Pennsylvania Department of Agriculture (PDA).
Christmas and other ornamental tree sales is an over $41 million per year industry in Pennsylvania, making the state fifth in the nation. The White Pine Weevil (WPW) is the major pest of many of these trees, including the eastern white pine, Colorado spruce, Norway spruce and Douglas fire. According to Cathy Thomas, Pennsylvania Integrated Pest Management Coordinator at PDA, the weevil is native to Pennsylvania forests and prefers nurseries because of the large fields planted with a single species of trees. "Across the state, WPW causes major financial injury to Christmas tree growers each year," says Thomas.
Typically, large quantities of pesticides are used to control WPW. According to Thomas, this practice puts largely unnecessary pollutants into the environment, increases the risk of pests developing resistance (immunity) to the pesticide, and increases the cost of production. In addition, EPA's Food Quality Protection Act is phasing out many of the traditional pesticides used in growing Christmas trees. "Increasingly, growers are looking for alternatives to traditional pesticides, but often lack the information and training to implement new approaches," Thomas explains.
One alternative to excessive pesticide applications is integrated pest management (IPM). IPM aims to manage pests -- such as insects, diseases, weeds and animals -- by combining physical, biological and chemical tactics that are safe, profitable and environmentally compatible. According to Thomas, growers using an IPM strategy to manage WPW will significantly reduce their pesticide applications.
Thomas and researchers from Penn State and PDA started working with three large Christmas tree growers totaling approximately 2,000 production acres in Schuylkill County earlier this year. Thomas says their first step was to educate the growers about the biology and life cycle of WPW to eliminate excessive, badly timed and ineffective pesticide applications. "The weevils produce one generation per year. In the early spring adult weevils, which have over-wintered in host trees, begin to feed on the tops of trees, causing dieback of the branches and making the tree unsuitable for sale," Thomas explains. "The tree is further damaged when the adult females deposit up to 200 eggs in feeding holes, causing the tree top to droop in the form a shepherd's crook, which is the distinguishing deformity of WPW damage. Starting from late July through August, the new adult weevils emerge and feed on the branches until they hibernate in winter."
To reduce growers' reliance on pesticides, the researchers are recommending IPM techniques such as crop scouting, pest trapping, and observation of growing degree days so that growers can be aware of peak pest activity and can synchronize insecticide applications that target the most susceptible life stage. In addition, PDA IPM specialist Linda Signaroviz trains the growers on a weekly basis. She works cooperatively with Penn State extension educators and PDA professionals to deliver these education programs at regional and statewide meetings.
In addition, researchers advise growers to use soft pesticides to replace the traditional pesticides they have been using. According to Thomas, these pesticides offer many benefits. "Soft pesticides are targeted to the pest, so they minimize negative effects on non-targeted, beneficial insects. This can prevent the increase of secondary pest population and will minimize the risk of WPW becoming pesticide resistant," Thomas explains. "In addition, using soft pesticides reduces worker exposure to toxic pesticide residues, as well as minimizes groundwater pollution and spray drift from ground and aerial applications. Moreover, growers can save money by reducing their chemical costs and subsequent fuel consumption during pesticide spraying."
At the end of the first year of the two-year project, Thomas says the results are very promising. "We've been able to achieve excellent control with scouting and trapping WPW. The three growers were able to reduce their pesticide use by 50 percent, and recorded a 20 percent reduction in tree damage. One grower reduced pesticide costs by over $2 hundred thousand," says Thomas.
Thomas is hoping that by initially working with three of the largest and most respected growers in the region, widespread adoption by small growers through out Pennsylvania will occur. Educational presentations of the data collected will be available for statewide use and additional training programs. The data is also available on the Pennsylvania IPM Program's 1-800 PENN IPM hotline and the Penn State Christmas Tree Web site at http://ctrees.cas.psu.edu/. For more information on Christmas tree pests, see PA IPM's Christmas Tree Pest Problem Solver at http://paipm.cas.psu.edu/259.htm. Questions about the project can be directed to Thomas by calling (717) 705-5857 or by e-mail at caththomas@state.pa.us.
The Pennsylvania IPM program is a collaboration between the Pennsylvania State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and nonagricultural situations. For more information, contact the program at (814) 865-2839, or visit Web site http://paipm.cas.psu.edu/. To view our archived news releases, see Web site http://paipm.cas.psu.edu/10.htm.