What are some common tree pests and diseases?

Trees attacked by pine beetles show several signs of infestation. Initially, you might see small holes in the bark and sawdust-like frass around the tree’s base or in the bark crevices. As the infestation progresses, the tree’s needles turn yellow, then reddish-brown, indicating the tree is under severe stress and likely dying from the inside. Pine beetles, such as the Mountain Pine Beetle, tunnel through the bark to lay eggs, disrupting the tree’s ability to transport water and nutrients.

The terms “pine bug” and “spruce bug” can sometimes be used interchangeably but generally refer to different types of pests that infest pine and spruce trees, respectively. Pine bugs might refer to pine beetle species that attack pine trees, causing damage by boring into the bark. On the other hand, spruce bugs often refer to pests like the Spruce Beetle, which explicitly targets spruce trees. Both bugs can cause significant damage to their host trees but have preferences for different tree species.

In Alberta, the little green bugs you’re likely encountering are Aphids. These small, pear-shaped insects are common in gardens and on trees, sucking sap from the plants and sometimes transmitting diseases. They come in various colours, but the green ones are most commonly seen. Aphids can reproduce rapidly, leading to large infestations that weaken plants and trees. They’re often managed through natural predators like ladybugs or the careful application of insecticides.

Alberta forests are home to various insects, including beneficial species and pests. Common pests include the Mountain Pine Beetle, Spruce Budworm, and Spruce Beetles, which can cause significant damage to forests. Beneficial insects, like ladybugs and various bees, play essential roles in pollination and controlling pest populations. The diversity of insect life is a crucial component of forest ecosystems, contributing to the health and balance of these environments.

Mites on trees are incredibly tiny, often requiring a magnifying glass to see clearly. They can appear as little dots moving on the leaves, sometimes with visible webbing, especially in the case of Spider Mites. Infested leaves might look dusty or have tiny spots where the mites have been feeding. Over time, heavily infested leaves can turn yellow-brown and eventually fall off the tree. If you suspect mites, a close inspection will reveal these minuscule pests actively moving on the underside of leaves or within their delicate, silky webs.

A Spruce Beetle is a dark brown to black beetle, about 4 to 7 mm long, making it relatively small but capable of causing significant damage to spruce trees. They bore into the bark to lay eggs, with the larvae feeding on the inner wood. This activity disrupts the tree’s ability to transport nutrients and water, often leading to the tree’s death. Signs of their presence include holes in the bark, sawdust-like frass, and fading foliage.