2026 Christmas Tree Scouting Report: April 16, 2026

Weather Summary

The past week has brought a rapid shift in weather across Pennsylvania, with several days of strong heat pushing temperatures into the upper 80s and even 90s. This resulted in a significant jump in growing degree day accumulation, with some areas gaining 20 or more GDD in a single day. When heat units build this quickly, crop development and pest activity do not move gradually, they jump forward fast.

We are seeing that play out in the field. Budbreak and shoot elongation have accelerated across multiple species, especially in full sun and southwest facing blocks. In some cases, trees moved from just beginning bud activity to widespread budbreak in only a few days. White spruce and Norway spruce in the 4 to 6 foot range moved from 1 to 2 percent budbreak to as much as 40 to 50 percent in a very short window. This type of movement highlights how quickly timing windows can open and close.

Soil temperatures have also stabilized, now holding in the mid to upper 50s, which is an important threshold for both root activity and insect movement. This contributes to the start of weevil activity, mite feeding, and overall increased pest pressure.

While cooler temperatures are expected next week, the progress made during this heat will not reverse. Needle elongation has already started in many areas, and pest activity has begun. Cooler weather may slow things slightly, but it will not reset development. At this point, crop stage needs to drive decisions, not the calendar.

Now is a critical time to be in the field. Conditions are changing quickly, and a gain of 20 GDD in a day can move a block from not ready to treat to past the ideal window. Regular scouting, especially every few days, is key. Pay close attention to bud stage, needle length, and pest presence to stay ahead of timing sensitive applications.

Pest and Disease Update 

White Pine Weevil

White pine weevil activity is just beginning to pick up. Initial trap catches have been reported in warmer areas, and this lines up with soil temperatures now holding in the mid to upper 50s. At this stage, adults are moving into terminals, but feeding has not yet been widely observed.

This is the window to act. Growers should be scouting the top 6 to 8 inches of terminal leaders on white pine, Norway and Serbian spruce, especially in open, sunny blocks. Adults will begin feeding and laying eggs shortly, and once larvae move under the bark, control is no longer effective.
If populations are present or historically an issue, applications should target adults now using labeled pyrethroids such as bifenthrin or permethrin. Good coverage of the terminal leader is critical, as that is where activity is concentrated. Bifenthrin, Permethrin, Lambda-cyhalothrin are all recommended active ingredients. 

Pales Weevil

Pales weevils are active and have been captured in traps. Activity is tied directly to fresh stumps, where adults feed and reproduce. If you have recently harvested blocks, those areas should be a priority.

Management should focus on treating fresh stumps as soon as possible after cutting. Labeled pyrethroids remain the primary option. Reducing breeding sites now will help limit population pressure moving forward.

Spruce Spider Mite

Spruce spider mite egg hatch is well underway, with roughly 75 percent or more hatch observed. Active feeding is occurring on spruce and arborvitae, particularly in warmer, exposed areas.

This is one of the best timings for control. Early season applications target the population before it builds and before webbing and damage become noticeable. Growers should scout by tapping branches over white paper to confirm mite activity.

If thresholds are met, miticides such as abamectin, bifenazate, or spiromesifen can be applied according to label directions. Refer to your miticide guide for rotation to prevent resistance. Early control here can prevent much larger problems later in the season.

Balsam Twig Aphid

Balsam twig aphids have progressed to the stem mother stage and are preparing to produce the next generation. This next flush of aphids will coincide directly with budbreak on balsam and Canaan fir.

If you have had damage in the past, now is the time to act. Once buds break and needles begin to expand, feeding will cause curling, distortion, and stunting that cannot be corrected.

Applications need to go on prior to budbreak. Materials such as imidacloprid or dinotefuran can be used according to the label, along with other options in your insecticide guide. Timing is everything here, once damage is visible, it is too late.

Pine Bark Scale and Pine Needle Scale

Pine bark scale and pine needle scale have been observed in Schuylkill and Lebanon County plantings. At this stage, populations are present but not yet at crawler stage.

Now is the time to flag those blocks and prepare to monitor for crawler emergence. That is when these insects are most vulnerable. Control options at crawler stage such as pyriproxyfen or buprofezin, along with systemic materials like dinotefuran or imidacloprid, can be applied according to label directions to achieve effective control.

Douglas Fir Needlecast

Douglas fir needlecast should be a top priority right now. Buds are swelling and breaking, and early needle elongation is occurring across many areas. In some blocks, new growth is moving quickly from tight bud to exposed needles within just a few days due to recent heat and rapid GDD accumulation. Some color change is already being observed in lower branches and interior foliage, indicating existing disease pressure and inoculum present within the canopy.

These diseases infect only the newly emerging needles, so protection must be in place before infection occurs. The first application of Bravo Weather Stik should be made at budbreak, just as needles begin to emerge from the bud and reach approximately one half inch to one to two inches in length. This same timing also marks the start of Swiss needlecast protection programs, as when new growth is ½ to 2 inches long, first fungicide applications for Swiss needlecast should begin. At this stage, needles are highly susceptible, and even a short delay in coverage can allow infection to occur during wet weather events.

This first spray is the foundation of the program and should not be delayed. As new growth continues to expand, additional applications are needed to maintain a protective barrier on all developing needles. A second application should be made 7 to 10 days after the first, particularly under current conditions where rapid elongation and rainfall can quickly leave new tissue unprotected. A third application should follow approximately 10 to 14 days after the second to extend protection through the primary infection period. In prolonged cool and wet conditions, additional applications may be required to maintain coverage.

Coverage is critical for effective control. Applications should be made with enough water volume to thoroughly coat all new growth, including interior branches and lower canopy where humidity remains higher and disease pressure is often greatest. Sprays should penetrate the canopy, not just cover the outer foliage. Adjust nozzle selection, pressure, and travel speed to ensure complete coverage of expanding needles.

Bravo Weather Stik is a protectant fungicide and will not control infections after they occur, reinforcing the importance of timing and maintaining continuous coverage on new growth. Once infection takes place, symptoms will continue to develop regardless of later applications.

During this early season timing, many growers will include an insecticide in the tank mix to address pests such as balsam twig aphid, adelgids, or other exposed feeding insects. Active ingredients such as bifenthrin or lambda-cyhalothrin are commonly used according to the label and can provide added value by controlling multiple issues in a single pass, as long as label compatibility and application conditions are followed.

Applications should be avoided during hot, dry periods, as high temperatures can increase the risk of phytotoxicity and reduce spray effectiveness due to rapid drying. Target applications during cooler parts of the day, including early morning or evening, when wind speeds are low to improve deposition and canopy penetration.

With rapid growth and changing field conditions, growers should monitor needle length closely and stay ahead of spray intervals. Once needles begin to elongate quickly, protection needs to be maintained consistently, as even a few days of unprotected growth during wet conditions can lead to infection.

Douglas Fir Needle Midge

Douglas fir needle midge traps are out, with no captures reported yet. However, emergence is expected as temperatures continue to rise and GDD accumulates.

Growers should keep traps checked regularly, as timing for control is very specific and tied to adult flight. Early detection is critical to ensure proper timing of any treatments. Many growers will spray for Needle Midge roughly one week prior to first application of Bravo.  During their first application of Bravo, they would also include an insecticide to help treat Needle Midge and other active insects such as adelgid and pitch moths. Some growers focus their attention for treatment more on trees that are within two years of harvest.

General Pest Pressure

Mite activity is present across all scouted areas and will continue to increase following the recent heat. Overall insect pressure is beginning to build and will continue to track closely with plant development.

Even though cooler weather is expected, pest activity will not stop. It will continue to move forward with crop stage. This makes continued scouting essential, especially in blocks that are moving quickly through budbreak and early shoot growth.

Other Nursery Crops

Fletcher Scale 

Fletcher scale is commonly found on arborvitae and can often go unnoticed until populations build. It appears as small, brown, dome-shaped scales attached to twigs and small branches. As populations increase, feeding can lead to yellowing or thinning foliage, along with the production of honeydew, which results in sticky residue and the development of sooty mold on foliage and surrounding surfaces. Fletcher scale overwinters as mature females on stems and becomes active in spring, feeding and producing eggs beneath the protective covering. Eggs hatch into crawlers in late spring to early summer, and this crawler stage is the most effective timing for control. At this point in the season, growers should be identifying and flagging infested plants and preparing to monitor for crawler emergence using tools such as double-sided tape on stems. Where populations are high, systemic insecticides such as imidacloprid or dinotefuran can be applied according to the label to help reduce populations. For best control, applications targeting the crawler stage should include materials such as pyriproxyfen, buprofezin, spirotetramat, or labeled pyrethroids, with thorough coverage of interior branches where infestations are often heaviest.

Next Report

The next scouting report will be available on April 23, 2026. Reminder, please submit observations anytime prior to Tuesday, April 21, 2026, by noon to Kelly Piccioni at keg200@psu.edu to be included in the next report. As a reminder, you may also call into the hotline weekly for updates: 1-800-PENN-IPM (1-800-736-6476) option 5. Important Note, Kelly Piccioni will be at horticultural programming and out of the office until April 27, and not readily accessible. Please feel free to reach out to local extension for green industry assistance. Kelly will respond to emails as quickly as possible.