Christmas tree pests target of new project

University Park, Pa. -- A new Penn State research project is helping six Pennsylvania Christmas tree growers keep invasive pests at bay while reducing pesticide use.

Under the direction of Cathy Thomas, Pennsylvania Integrated Pest Management (IPM) coordinator, the project will focus on scale pests from Asia such as Elongate hemlock scale and Cryptomeria scale that cause a lot of damage to hemlock and fir trees. "Scale pests attack Fraser, canaan and balsam firs, all of which are important Christmas tree varieties in Pennsylvania," said Thomas.

The scales are difficult to control with pesticides because they have two generations each year and adults having a waxy, armored-like covering. In addition, many of the pesticides used to control scales and other insect pests are broad-spectrum and also kill natural predators of the scales. Thomas and Sarah Pickel, Pennsylvania IPM program associate, are working with growers to develop better scouting and monitoring techniques, which will allow for fewer applications and substitution of safer chemicals.

Scouting, monitoring and the substitution of safer chemicals are all part of an integrated pest management program. 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.

Thomas said they are working with six growers in Schuykill and York counties. "We collaborate with Pennsylvania Department of Agriculture entomologists and plant inspectors in the field using IPM techniques such as scouting, weather monitoring and record keeping so we know what pests are in the field and at what life stage," said Thomas, who also provides on-site training for growers on scale life cycles and IPM techniques.

In a previous Pennsylvania IPM project targeting white pine weevil, Thomas helped three conifer growers in Schuylkill County reduce pesticide use by more than 50 percent by using an IPM approach. As a result, growers were able to produce high quality conifer trees while substantially reducing pesticide use, which resulted in improved profitability. Thomas expects similar results with the scale project.

In addition, Thomas plans to develop a conifer pest-scouting manual to help participating and non-participating growers to incorporate IPM techniques into their farm operation. "Several conifer/Christmas tree manuals exist, but none are specific to Pennsylvania. With the help of specialists at Penn State and the state Department of Agriculture, conifer growers will be able to directly access regionally pertinent IPM advice from experts in the industry," Thomas explained.

The project also aims to establish a crop management association to help growers transition to a system of employing IPM techniques. "A trained consultant will provide grower with professional IPM services and promote more economical and environmentally sound crop production practices," said Thomas.

The project is being funded by a grant from state Department of Agriculture agricultural research funds. Educational presentations of the data collected will be available for statewide use and additional training programs. The data will also be available on the Pennsylvania IPM Program's (800) PENN IPM hot line and the Penn State Christmas Tree Web site at For more information on Christmas tree pests, see Pennsylvania IPM's Christmas Tree Pest Problem Solver at Questions about the project can be directed to Thomas by calling (717) 772-5204 or by e-mail at

The Pennsylvania IPM program is a collaboration between the Penn State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and urban settings. For  information, contact the program at (814) 865-2839, or Web site

Last Updated March 19, 2009