As temperatures drop across Virginia, many residents breathe a sigh of relief, assuming that insect problems vanish with the first frost. However, fall and early winter bring their own set of pest challenges that can threaten the health of trees and shrubs.
Some insects remain active during cooler months, while others overwinter in ways that cause damage come spring.
| In This Article: Learn about the most concerning tree pests Virginia residents should monitor during fall and early winter, along with guidance on protecting your landscape investment. |
Pro Tip: Why Fall and Winter Pest Monitoring Matters
The cooler seasons offer a deceptive calm in the landscape. While many insects become less visible, several species use this time to establish themselves for the next growing season. Fall provides an ideal window for detection because deciduous trees lose their leaves, making signs of infestation more apparent. Some pests remain surprisingly active when temperatures stay mild, which Virginia’s climate often permits well into November and December.
Knowledge of pest life cycles helps property owners time interventions effectively. Professional arborists can identify early warning signs that untrained eyes might miss, preventing minor issues from becoming serious threats.
Hemlock Woolly Adelgid
This invasive pest poses one of the most serious threats to Virginia’s hemlock trees. The hemlock woolly adelgid appears as tiny white, cotton-like masses on the undersides of hemlock branches, evident during fall and winter when the insects are most active. These adelgids consume sap from the base of needles, disrupting nutrient flow, ultimately leading to needle loss, branch dieback, and tree death.
The hemlock woolly adelgid has been affecting hemlock trees in the eastern United States since it was inadvertently introduced in the 1950s. Because this pest flourishes in cooler temperatures, fall and winter inspections become especially important. Timely detection provides treatment opportunities that can preserve valuable hemlock specimens before permanent damage takes place.
Scale Insects
Various scale species remain problematic during Virginia’s cooler months. These insects, whether armored or soft-bodied, cling to bark and branches and consume plant fluids during the winter months. Euonymus scale, pine needle scale, and oystershell scale are widespread on ornamental plants and trees across the state.
Winter provides an excellent time to spot scale infestations because their protective coverings stand out against bare branches. Severe infestations can weaken plants, leading to yellowing leaves, stunted growth, and increased vulnerability to other stressors. Professional treatment during the dormant season can significantly reduce scale populations before spring growth begins.
Winter Moths and Cankerworms
These caterpillars emerge in late fall and early winter, and the adult moths fly when temperatures hover around 40 degrees Fahrenheit. Female winter moths are flightless and crawl up tree trunks to lay eggs, which will hatch in spring. The resulting caterpillars can completely defoliate trees, particularly maples, oaks, elms, and fruit trees.
Signs of winter moth and cankerworm activity include:
- Small brown moths flying near trees on mild winter evenings
- Egg masses on branches and trunks
- Previous season’s defoliation damage
- Sticky bands around tree trunks from earlier treatments
Preventing female moths from climbing trees in the fall is the most effective control strategy. This necessitates timely intervention by professionals knowledgeable about the pest’s life cycle.
Bagworms
While bagworms cause most of their feeding damage during summer, their protective bags, which contain eggs, remain attached to branches throughout fall and winter. These spindle-shaped bags, often mistaken for pinecones or natural seed pods, house hundreds of eggs that will hatch in late spring. Evergreens such as arborvitae, juniper, and spruce are particularly susceptible, though bagworms also attack deciduous trees.
Removing bags during winter prevents the next generation from emerging, but this requires careful inspection and proper removal techniques. The Missouri Botanical Garden identifies bagworms as persistent pests requiring vigilant monitoring. Missing even a few bags can lead to renewed infestations.
Emerald Ash Borer
Though emerald ash borer larvae feed beneath bark year-round, fall offers excellent timing for detection and treatment. This metallic-green beetle has severely harmed ash tree populations throughout a large portion of the eastern United States. D-shaped exit holes, woodpecker damage, and crown dieback become more noticeable once leaves drop.
The emerald ash borer is responsible for the death and decline of tens of millions of ash trees in North America. Because this pest kills ash trees within two to four years of infestation, prompt professional assessment and treatment planning are essential for preservation.
Protecting Your Property Investment With RTEC Treecare
Fall and early winter pest monitoring requires trained expertise to identify subtle signs of infestation and implement appropriate treatments. These pests endanger not just individual trees but also property values and the general well-being of landscapes in Virginia.
RTEC Treecare provides nearly three decades of environmentally responsible tree care to homeowners throughout Virginia. Our ISA-certified arborists understand the seasonal challenges that tree pests pose to Virginia properties and can develop customized management plans aligned with preservation-based practices. Rather than waiting until spring reveals the full extent of pest damage, contact RTEC Treecare today for a professional assessment.
Call (703) 573-3029 or contact us online, and we’ll help you safeguard your trees through professional diagnosis, proven treatment methods, and an ongoing partnership to maintain your property’s long-term landscape health.
