Christmas Tree Scouting Report: April 10, 2025

Weekly newsletter compiled by Kelly Piccioni, Penn State Extension. This week's scouting data contributors: Kelly Piccioni (Penn State Extension), Jim Fogarty (Halabura Tree Farm), Don deMackiewicz, Sarah Pickel and Cathy Thomas (PA Department of Agriculture).

Pest Information

Drought is going to be the lingering word to be referenced throughout this report and most likely, the rest of the season. The lasting impacts from last year's drought, (and don't forget the previous season's), coupled with very low temperatures and high winds this season, evergreens are showing massive winter desiccation.  Because the plants entered the winter with limited stored resources in the root system due to drought, the winter transpiration and high winds simply dehydrated these plants. The symptoms are showing boldly in the fields and in landscapes this early spring.  Secondary infections will be likely, so Be Alert and Scout in your fields. IPM for Christmas Tree Production is a good resource for learning how to scout and monitor properly.

White Pine Weevil

Although we had a few warm days, our nights have remained cold enough to keep activity at bay. We are still finding one or two White Pine Weevils in the traps weekly, but not at the levels where the application of pesticide is recommended. When scouting with Jim Fogarty this week, he mentioned a good tip for scouting active White Pine Weevils when you do not have traps to monitor. Look, from a distance, at the leaders of the tree and you will see the sap shine as this sun hits it. A pair of binoculars may also facilitate this step for easier viewing on taller trees. You will also view exit holes with sap exuding from the feeding holes. Once the adults are actively feeding, spray application will be most productive for control.

In conversations with growers and other extension educators this week, White Pine needle diseases may be more active after coming off two drought-impacted growing seasons. Take a look at this Penn State Extension article on Eastern White Pine for historical information as well as disease issues.

Douglas Fir

Needle Cast is observable at this time. There have been many observations and calls of concern regarding the larger-than-normal number of impacted trees. Keep in mind that those drought impacts weaken the overall vigor of a plant in fighting pests and diseases. The trees are more susceptible to infection and infestation under these conditions. Soil test, scout in the fields, and be timely with your applications of pesticides starting at bud break.

Growers who have had problems in previous seasons with Douglas fir needle midge, a fly-like pest that causes galls to form within the needles, will want to watch for this pest as the buds of Douglas fir begin to swell. Another monitoring tool that could be useful to these growers is an emergence trap. This simple trap, constructed of a cardboard box and clear plastic jar, captures the adult midges as they emerge from the soil beneath the trees.

Spruce Spider Mites

The eggs of spruce spider mites have started to hatch in Schuylkill Counties in low numbers, with eggs starting to change colors. The cool nights have slowed this progression. Growers should be monitoring for egg hatch as the weather begins to warm up. Trees that had damage last season will show a yellowing or browning of the needles beginning near the stems.  The eggs will be found on the underside of the twigs, at the bases of the needles. A simple way to check for egg hatch is to hold a white paper underneath a branch and tap the branch to dislodge the eggs. If the tiny red specks begin to move, the mites have hatched. A hand lens is a valuable tool when looking for this. 

Balsam Twig Aphid

A few pale green stem mothers have been observed by growers in Schuylkill Country feeding on Fraser Fir. These aphids will only be found on true firs, where damage is easily recognizable as a twisting or kinking of last season's new needles. As true fir bud break draws near, stem mothers will give birth to live young, which will move into the opening buds and begin to feed on the newly developing needles. This is what causes the damage. Once the aphids move inside the buds, control measures will not prevent damage.

General Information:

The weather has been wild this spring so far, but stay vigilant with scouting. Once the weather turns and soil temperatures rise along with night temperatures, activity of these pests will quickly rise. For more severe questions or desire to have material tested, please visit the Penn State Plant Disease Clinic for more information to submit samples.  Please keep sending scouting information to Kelly Piccioni at keg200@psu.edu 

The next scouting report will be available: April 17, 2025