Penn State Extension released its Christmas Tree Scouting Report for April 30, according to an announcement on Apr. 29. The report details current pest and disease conditions affecting Christmas tree species across Pennsylvania, along with recommendations for growers in the coming weeks.
The scouting report is important for local growers because it provides timely updates on pest activity and disease risks, helping them make informed decisions about crop management. This guidance supports efforts to maintain healthy trees and sustain agricultural productivity in the region.
According to the report, frost injury remains present but limited across Douglas fir, Concolor fir, and Norway spruce. In York County, about 20 percent of branch tips sampled showed damage from recent low temperatures; other counties reported lower or minimal injury. Most evergreens are expected to continue normal growth despite these events.
Pest monitoring revealed that Douglas fir needle midge has been detected in Schuylkill County, with adult activity underway as growing degree days accumulate. Treatments are being applied in alignment with host development stages. Balsam twig aphid populations appear under control following recent treatments targeting budbreak periods between 100 and 250 growing degree days. Heavy populations of spruce spider mites have been observed in some plantings; early-season control using miticides like abamectin and spirodiclofen is recommended due to rapid population growth under current conditions.
Other findings include observations of elongate hemlock scale eggs beneath coverings on Fraser fir needles; crawler emergence is expected soon between 360 and 450 growing degree days—this stage offers the best timing for control measures using systemic products such as dinotefuran or imidacloprid. White pine weevil activity was not detected during this period after most Southeastern Pennsylvania sites had already implemented treatments based on soil temperature thresholds.
On the disease front, spruce needle rust has not yet been observed but may be present at low levels during budbreak through early needle expansion (200–350 growing degree days). Management programs should focus on protecting new needles each spring using chlorothalonil or mancozeb products in a multi-application approach if wet weather persists.
Looking ahead, Penn State Extension recommends continued monitoring over the next two weeks as pests like Douglas fir needle midge become more active and diseases remain a risk during ongoing shoot elongation phases. The next scouting report will be available May 7; growers can submit observations before noon on May 5 by contacting Kelly Piccioni at keg200@psu.edu or calling the hotline at 1-800-PENN-IPM (option 5).
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