2026 Christmas Tree Scouting Report August 5, 2026

Pest Alert:

Scouting throughout southeastern and central Pennsylvania has confirmed that the second generation of Cryptomeria scale is now active, with both eggs and crawlers present. These crawler stages are the most susceptible life stage for management where populations warrant treatment. Scouting has also revealed encouraging signs of natural biological control. On some fir needles, scales had been completely removed, leaving behind only the clear feeding scars where beneficial insects had consumed both adult scales and immature stages. These observations highlight the importance of scouting before making treatment decisions, as beneficial insects can provide meaningful suppression of Cryptomeria scale populations, particularly where broad spectrum insecticide use has been minimized.

Cryptomeria Scale 

The second generation of cryptomeria scale crawlers has emerged in Southeastern PA. It is now time to scout your fields and evaluate if it is time to treat. Second-crawler emergence roughly aligns with 1,750–2,130 GDD (base 50°F) accumulation. To scout, focus on the undersides of needles, particularly on lower and inner branches where infestations often start. Trees with mottled yellow needles are common indicators of scale activity.

To detect crawlers, use sticky tape by wrapping double-sided or sticky black electrical tape with the adhesive side facing outward around twigs or needles on infested trees. This will capture the tiny, flattened yellow crawler stage before they form their protective shields. Crawlers are most vulnerable at this stage, making it the optimal window for control measures. Yellow sticky cards may also be used to track male flights and help time applications.

Cryptomeria scale infestations can affect Fraser firs of all sizes, not just larger market-ready trees. Regardless of tree height, timely intervention is essential to reduce scale populations, prevent spread, and maintain overall crop quality and health. The following plan offers a comprehensive strategy for both immediate knockdown and long-term suppression, using a combination of insecticides, cultural controls, and scouting practices tailored to trees at different developmental stages.

In addition, dead scales were observed in several plantings, suggesting that previous management efforts may still be providing control. As growers evaluate their fields, some may determine that a second insecticide application is not necessary, while others with higher populations or continued crawler activity may benefit from additional treatment. This is a farm by farm decision that should be based on careful scouting, the level of live scale present, and the amount of natural biological control occurring within each planting.

For growers who missed the first-generation spray window and are facing heavy Cryptomeria scale infestations on Fraser firs, immediate and strategic action is essential to bring these trees to market quality. Begin with Dimethoate for rapid knockdown. Apply at 1 pint per 100 gallons of water, ensuring thorough coverage. Avoid spraying during heat stress (>85°F), and reapply in 10–14 days if crawler activity continues. This product offers quick suppression, but its broad-spectrum nature can flare secondary pests such as spider mites. To minimize this, scout regularly and consider rotating with softer products such as Safari or Movento later in the season.

Movento (spirotetramat) should be applied during active tree growth, typically in late August through early September. Use at 6–9 fl oz per acre with a non-ionic surfactant to ensure systemic uptake. This product offers longer-term suppression and is softer on beneficial insects. Apply only when trees are actively photosynthesizing to ensure movement within the plant.

Culturally, remove and burn heavily infested or non-sellable trees to reduce inoculum and open the canopy for better spray coverage and air circulation. This step also reduces overwintering populations of scale and other pests. Avoid chipping heavily infested trees unless they can be composted at high heat away from production areas.

Monitor mite populations closely if Dimethoate is used. If mite levels increase, consider introducing miticides like hexythiazox or bifenazate if thresholds are exceeded, or encourage predatory mite activity by minimizing disruptive sprays. Mites thrive in dusty, dry environments, so irrigating and maintaining vegetation between rows can help suppress outbreaks.

Proper fertilization supports scale recovery but must be timed carefully. Apply balanced fertilizer in early spring to promote healthy flushing. Avoid late-summer nitrogen applications, which can encourage tender growth susceptible to pests and winter injury. Excess nutrients may also increase scale susceptibility and reduce tree form if growth is uneven.

Next Report

The next report will be published August 13, 2026.  If you have any pests to report on, or any other important information to share with growers, please report it to Kelly Piccioni at keg200@psu.edu by Tuesday August 12th.