Pests and Diseases
Pests and diseases can have a severe impact on the health and economic output of forests. On this page, access educational resources on private forest pests and diseases. Additionally, find information on spotted lanternfly, worms, caterpillars, weevils, mites, knotweed, multiflora rose, and invasive weeds.
Invasive Forest Insects
Invasive, non-native insects compete with native species, affect local habitats, and alter the forest’s ecosystem. Invasive insect pests, such as the spotted lanternfly (SLF), are a serious ecological threat for Pennsylvania forests.
The spotted lanternfly feeds on many plants but is particularly attracted to the tree-of-heaven, an invasive forest tree. Comprehensive SLF management resources, as well as permit training for business, are available through Penn State Extension.
The emerald ash borer (EAB) is another destructive insect that can be encountered in PA forests. EAB is a wood-boring beetle that has caused the decline and mortality of many North American ash trees. Explore recent control efforts for EAB and other invasive forest pests during the Invasive Insects webinar.
Common Forest Pests and Diseases
Pests and diseases have a significant impact on forest ecosystems. They can affect leaves, stems, and crowns, which in turn can damage the condition and growth of trees. What is more, forest pest and disease issues can reduce wood quality and yields.
Cankers are among the more widespread tree problems. They can affect species such as elm, beech, and hemlock trees. In this section, you will discover informational tables on prevalent forest diseases, including ash, maple, and oak diseases. Private forest owners can learn how to diagnose and manage elm, beech, hemlock, and pine diseases as well. Tips on symptoms, causes, and management tactics are available.
Pennsylvania forests can be attacked by various pests, as well. A typical native pest of hardwood trees in North America is the fall cankerworm. Mature larvae feed on leaves and can often defoliate an entire tree.
Other forest insects, such as the tuliptree scale, can cover twigs and branches, resulting in a rapid tree decline. Landowners should further remain alert for signs of infestations caused by eastern tent caterpillar, birch leafminer, and white pine weevil.
Private Forests and Pest Management
Forest pest management is primarily focused on preventing the entry and spread of invasive species while maintaining the woodland’s biological health. Pest control options include biological, mechanical, and chemical methods, typically depending upon the damage-causing species. With pests such as the engraver beetle, chemical control is generally only necessary for high-valued trees in residential or recreational settings.
In many forests, invasive vegetation control is needed, as well. Before applying any herbicides, consider the Integrated Vegetation Management approach to ensure a healthy forest ecosystem.
Detailed information on identifying and managing forest diseases and pests can be obtained through Penn State Extension. Resources are also available on topics such as becoming a certified forest pesticide applicator, as well as managing tree-of-heaven as part of SLF control strategies.
- Articles
Preparing for High Spongy Moth Densities
Periodic Lymantria dispar, or spongy moth (formerly "gypsy moth"), outbreaks cause defoliation stress to many plant species. Know what to expect and what management options to consider when an outbreak occurs. - News
Forest Snapshot March 2024
Date Posted 3/20/2024This bi-monthly article is a collection of forest health observations, plant and animal phenology, important upcoming dates, and hunting season changes. - Articles
Beech Leaf Disease
This article discusses the cause of beech leaf disease (BLD), the lifecycle of this nematode (Litylenchus crenatae ssp. mccannii), the symptoms of BLD, and treatments. - Webinars
Free
Frontiers in Forest Health: Managing Spongy Moth
When Watch NowLength 1 hour, 15 minutesRecorded Feb 27, 2024Perfect webinar for foresters, loggers, and wildlife biologists! Learn about the Spongy Moth's history, biology, and management tools. Earn 1 credit from ISA and SAF. - Webinars
Frontiers in Forest Health: Asian Longhorned Beetle
Length 1.25Examine the invasion history, assess impacts on urban and rural forests, learn prevention strategies, and explore management techniques for areas affected by the Asian longhorned beetle. - News
Frontiers in Forest Health
Date Posted 2/9/2024This is a series of webinars about emerging threats to forest health across the Eastern United States. - Webinars
Free
Frontiers in Forest Health: Beech Leaf Disease
When Watch NowLength 1 hourRecorded Jan 18, 2024Explore everything about this affliction: recognizing it, its origins, and the risks it poses to forests. Additionally, delve into the latest research and potential strategies to manage beech leaf disease. - Videos
Silent Survivors: The Winter Life of Trees
Length 4:43Trees face climatic challenges each winter in their mission to add another annual ring of growth. This video explores a few important ways trees endure the winter months. - Articles
Silent Survivors: The Winter Life of Trees
Trees have many enemies. Insects, diseases, wildlife, and fungi are among the cast of characters that harm them throughout their lives. Trees also face climatic challenges. - Articles
Brown Rot in Wood
Brown rot, sometimes called cubical brown rot, is one type of decay fungi that can attack wood that leaves the wood with a reddish color and small, cube-shaped pieces of wood. - Articles
Spotted Lanternfly Management Guide
Publication providing comprehensive details on the spotted lanternfly, including identification and life cycle; quarantine and distribution; host range, phenology, and damage; and management. - Articles
What Should You Do With Spotted Lanternfly Egg Masses?
Information about locating, identifying, and treating egg masses. - Articles
Spotted Lanternfly Frequently Asked Questions
Get the answers to the most frequently asked questions about spotted lanternfly, including their damage to plants, how to manage them on your property, and what you can do to help! - Articles
Elm Spanworm
The elm spanworm is a serious defoliator of hardwood shade and forest trees in the eastern United States. - Articles
Deciding If and When to Treat for Spotted Lanternfly on Ornamentals
Some insect pests have one life stage that is especially vulnerable to insecticides but have other life stages that are harder to control. Spotted lanternfly is different. - Articles
Spotted Lanternfly Management Resources
The public can do a great deal to stop the spread of the invasive Spotted Lanternfly, join us to learn what you can do to help! - Articles
Fall Cankerworm
The fall cankerworm is a native pest of hardwood trees in North America. It causes some defoliation in the forest every year, with larger outbreaks occasionally. - Articles
White Pine Weevil
The white pine weevil is considered the most destructive insect pest of eastern white pine in North America. - Articles
Tuliptree Scale
The tuliptree scale is a pest of yellow poplar, or tuliptree, magnolia, and linden. This soft scale insect is so prolific that it can cover twigs and branches. - Articles
Spruce Spider Mite
The spruce spider mite attacks spruce, arborvitae, juniper, hemlock, pine, Douglas-fir, and occasionally other conifers. - Articles
Elongate Hemlock Scale
The elongate hemlock scale, sometimes known as the fiorinia scale, is a serious armored scale insect pest on ornamental and forest hemlock trees in Pennsylvania. - Articles
Control Forest Pests by Becoming a Certified Pesticide Applicator
Certified pesticide applicators are needed to assist with forest management activities. This article provides a step by step approach to become a certified forest pesticide applicator. - Videos
Eastern Hemlock Health Update
Length 4:09The Eastern Hemlock has suffered a long onslaught from a "little-bugger" named Hemlock Wooly Adelgid, or "HWA" for short. This video provides an update on this formidable forest pest. - Articles
Western Conifer Seed Bug
Western conifer seed bugs feed on conifer seeds and cones. They can be a nuisance to homeowners when they move indoors to overwinter in the fall. - Articles
Spotted Lanternfly: What to Look For
Spotted Lanternfly, Lycorma delicatula, is a new threat to Pennsylvania and the United States, and experts are still learning how to combat it.