2026 Christmas Tree Scouting Report July 1, 2026

Report Information 

An extended period of exceptionally hot weather dominated much of Pennsylvania this week as a persistent heat dome settled across the eastern United States. Southeastern Pennsylvania experienced several consecutive days with daytime temperatures climbing well into the 90s, while heat index values exceeded 100°F in many locations. Combined with below normal rainfall, drought stress is becoming increasingly evident across many Christmas tree farms. Although scattered thunderstorms developed in some areas, rainfall was highly variable, leaving many farms with little measurable precipitation and continued soil moisture deficits.

The prolonged heat has accelerated shoot maturation while naturally reducing populations of several cool season pests. At the same time, environmental stress is increasing on newly planted trees, shallow rooted species, and plantations growing on lighter or well-drained soils. As summer progresses, growers should expect drought stress to become a more significant factor influencing overall tree health.

Heat and Drought Stress

The current heat wave is expected to influence tree health well beyond this week. Symptoms such as premature needle yellowing, interior needle drop, reduced shoot growth, and occasional branch dieback may be associated with prolonged heat and drought stress rather than insects or diseases alone. Trees growing on ridge tops, sandy soils, south-facing slopes, and recently established plantings are likely to exhibit symptoms first. Environmental stress may also make spring frost injury, needle cast diseases, and other underlying problems more apparent as the season progresses.

When evaluating affected trees, pay close attention to patterns of injury. Symptoms occurring uniformly across field edges, hilltops, or drought-prone soils often indicate environmental stress rather than a biotic pest. If possible, postpone nonessential herbicide applications until temperatures moderate and trees recover from heat stress. Likewise, delay unnecessary insecticide and fungicide applications unless scouting indicates treatment is warranted and product labels allow applications under current environmental conditions. When treatments cannot be postponed, make applications during the coolest portions of the day and carefully follow all label precautions regarding temperature and drought stress.

Pest Information

Cryptomeria Scale

Spring management programs continue to show excellent results throughout monitored plantations. No live cryptomeria scale were detected during this week's scouting, indicating that crawler applications were well timed and highly effective. Applications coincided closely with first generation crawler emergence, resulting in excellent control before crawlers settled beneath their protective wax covers.

Growers should now begin looking ahead to the second generation of crawlers, which typically begins emerging during mid to late August in Pennsylvania at approximately 1,750 to 2,100 growing degree days (base 50°F). Careful scouting during this period will help determine whether additional management will be necessary.

Elongate Hemlock Scale

Elongate hemlock scale populations also remain extremely low following spring applications. No live scales were observed during inspections this week, even in plantations with previous infestations. Excellent control was achieved despite many crawlers having already settled, suggesting that applications were made before protective wax covers had fully developed.

These observations reinforce the importance of properly timing applications to crawler emergence, which remains the most effective management strategy for both elongate hemlock scale and cryptomeria scale.

Douglas-fir Needle Cast

Symptoms of needle cast diseases continue to develop on last year's Douglas-fir needles in several plantations. Browning and chlorosis of one-year-old needles were readily apparent despite preventative fungicide programs. As infected needles continue to decline, needle loss is expected to increase through late summer, fall, and into winter, resulting in thinner canopies on affected trees.

It is important to remember that fungicides protect healthy needles from new infections but cannot cure needles that were infected during previous infection periods. Weather conditions during the spring likely reduced fungicide performance in some locations despite properly timed applications. The success of this year's fungicide program on the current season's growth will not be fully evaluated until next spring.

Spruce Needle Cast Diseases

Needle cast symptoms are becoming increasingly noticeable on several spruce species, particularly Norway spruce, Colorado blue spruce, and white spruce. Browning and premature loss of older needles may now be evident as infections that occurred during cool, wet weather this spring continue to develop. Depending on the pathogen involved, symptoms may include purple to brown discoloration of one- and two-year-old needles, premature needle drop, and thinning of the lower and interior canopy.

Several needle cast diseases occur on spruce in Pennsylvania, including Rhizosphaera needle cast and Stigmina needle blight. These diseases often develop slowly over multiple years, with repeated defoliation reducing tree density and overall marketability. Fruiting structures may be visible on infected needles using a hand lens, but laboratory diagnosis may be necessary to distinguish among pathogens.

As growers shear plantations this summer, inspect spruce blocks for thinning canopies, lower branch defoliation, and patterns of needle loss. Mark affected trees or blocks now so preventative fungicide programs can be planned for next spring. Once symptoms become visible, fungicides cannot restore infected needles or replace foliage that has already been lost. Successful management depends on protecting newly emerging needles during spring infection periods over consecutive years while also improving air movement through proper spacing and weed management where practical.

Spruce Spider Mites

Spruce spider mite populations have declined dramatically across monitored sites. No live spruce spider mites were observed this week, including in plantations that supported moderate populations earlier this spring. The combination of successful spring management and prolonged summer heat has resulted in excellent suppression of this cool-season pest.

Only isolated two spotted spider mites were observed, and populations remain well below treatment thresholds. No miticide applications are recommended at this time. Continue routine monitoring during periods of prolonged hot, dry weather, particularly in drought-stressed blocks, where two spotted spider mites may become more active later this summer.

White Pine Weevil

Low levels of white pine weevil damage were observed this week on Norway spruce, Serbian spruce, and white pine. Many growers have begun shearing and corrective pruning, making this one of the best times of the season to evaluate the extent and distribution of weevil injury throughout the plantation. As crews move through the fields, take advantage of the opportunity to identify affected blocks, estimate damage levels, and record problem areas that may require additional attention next spring.

Infested terminals are now readily visible as leaders wilt, curl, or turn brown. Remove damaged leaders several inches below the lowest visible tunneling or discoloration, cutting into healthy wood to ensure larvae or pupae are removed. Developing white pine weevils can often be found beneath the bark of infested terminals. Destroy removed leaders rather than leaving them in the field, as insects may continue their development if infested material is not properly disposed of.

This is also an excellent time to mark affected blocks on field maps or in scouting records. White pine weevil infestations frequently recur in the same areas from year to year, particularly along field edges, roadways, hilltops, and other warm, exposed sites favored by overwintering adults. These observations can greatly improve the timing of next spring's management program.

Growers with a history of white pine weevil should also consider placing Tedders pyramid traps next spring to monitor overwintered adult activity. Preventative insecticide applications are most effective when timed against adults before egg laying begins. Combining good scouting records, sanitation pruning, trap monitoring, and properly timed spring applications remains the most effective long-term management strategy.

Canaan Fir

Weather-related injury continues to be evident on Canaan fir in several monitored plantations. Symptoms include scattered browning of needles, branch flagging, and localized shoot dieback that appear to be associated with winter injury and environmental stress rather than active insect or disease problems. In many cases, symptoms have become more noticeable as trees continue to grow and the recent heat and drought have placed additional stress on affected trees.

As growers move through plantations shearing and making corrective cuts, take time to closely inspect Canaan fir for scattered areas of decline, poor bud development, winter injury, or other abnormalities. Note whether symptoms are isolated to individual trees or occurring across specific portions of a field, such as hilltops, exposed areas, or poorly drained sites. These observations can help distinguish environmental injury from insect or disease issues and provide valuable information when planning future management decisions. Marking affected blocks and documenting symptom severity now will also make it easier to monitor recovery or continued decline over the coming seasons.

Bagworm

Most bagworm larvae have completed feeding and are becoming increasingly difficult to control as they enlarge and become protected within their bags. In many plantations, treatments are no longer economical once larvae reach the later instars. Continue scouting susceptible species, including arborvitae, juniper, spruce, and fir, to identify localized infestations and hand remove bags where practical.

As summer progresses, growers should begin planning for pheromone trap deployment during August. Male bagworm moths typically begin emerging from late August into September, depending on location and seasonal temperatures. Pheromone traps provide an excellent tool for monitoring adult flight, identifying persistent infestation hotspots, and documenting year-to-year population trends.

Now is also an excellent time to mark fields with recurring bagworm problems while damage is still visible. Recording infestation locations and maintaining accurate scouting records will improve management decisions next spring when newly hatched larvae are most susceptible to treatment. Since each female remains inside her bag and deposits several hundred overwintering eggs before dying, identifying problem areas now can significantly improve next year's bagworm management program.

Spotted Lanternfly

Second instar spotted lanternfly nymphs were observed this week in southeastern Pennsylvania. At this stage, nymphs remain black with distinctive white spots and continue feeding on a wide range of herbaceous plants, shrubs, and trees. As the season progresses, nymphs will molt into the third instar before reaching the easily recognized fourth instar, which is bright red with black and white markings.

Although spotted lanternfly is not considered a significant pest of Christmas trees, growers should continue monitoring populations along field edges, in woodlots, and in nearby vegetation. Nymphs are highly mobile and may be found on a variety of host plants before moving to preferred late-season hosts. The appearance of the bright red fourth instar later this summer often signals increased visibility and public concern, even though management decisions should continue to be based on population levels and host plants rather than appearance alone.

For growers who also produce nursery stock, grapes, or other susceptible crops, now is a good time to monitor surrounding vegetation and remain aware of local population increases as nymphs continue to develop throughout the summer. For more information watch this Spotted Lanternfly video.

Looking Ahead

The first generation of many important insect pests has concluded, making this an excellent time to evaluate the success of this spring's management programs. As growers continue shearing and summer pruning, inspect plantations for white pine weevil injury, needle cast diseases, winter injury, drought stress, and any surviving insect populations. Mark problem blocks, document treatment successes and failures, and make notes while observations are fresh. These records will improve management decisions next season.

If the current period of extreme heat and drought continues, prioritize irrigation where available and postpone nonessential herbicide and pesticide applications until temperatures moderate. Continue monitoring trees for symptoms of environmental stress that may become more evident as the summer progresses.

The next Pennsylvania Christmas Tree Scouting Report will be released as second generation cryptomeria scale crawlers begin emerging, typically during mid to late August between approximately 1,750 and 2,100 growing degree days (base 50°F). Growers are encouraged to monitor local growing degree day accumulations using GreenCast Online, as crawler emergence will vary across the Commonwealth.

Upcoming Meetings

Kelly looks forward to seeing many of you at the Pennsylvania Christmas Tree Growers Association Summer Meeting. A review of this season's major insect and disease issues and spend time in a hands-on scouting workshop featuring interactive stations. The focus of the workshop is simple: learning what to look for before problems become costly and becoming more confident in scouting your own farms.

Kelly will also be presenting at the Virginia Christmas Tree Growers Association Summer Meeting, where she will be speaking on Christmas tree scouting and integrated pest management, followed by a hands-on workshop demonstrating Christmas porch pot design and discussing value-added opportunities for Christmas tree farms.

Thank you for following the Pennsylvania Christmas Tree Scouting Report throughout the first half of the growing season. Stay cool, stay safe, and happy pruning and scouting! We will report when the crawlers from the second generation of Cryptomeria scale emerge. Report any findings to Kelly at keg200@psu.edu