Insect & Disease
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Signs of pests and diseases will vary from tree to tree. Search our database of pests and diseases for symptoms, damages, life cycle, management, and control information.

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Pest And Disease Ash Rust Banner 1440X500

Spotting on Leaf

Ash Leaf Rust

Ash leaf rust can be a significant problem in the Mid-Atlantic area and along the New England coast. Leaves, petioles and green twigs become infected during May and June. When the infection is severe, premature defoliation can occur.

Webs or Bags

Bark Lice

Bark Lice are small, dark-colored insects that produce fine, dense webbing on the trunks of host trees. Varying in color from tan to black, these pests may or may not have wings, and are usually less than five millimeters long.

Leaf or Needle Discoloration

Boxwood Decline

Boxwood decline is a condition that causes weak growth, discoloring of leaves and branch dieback in boxwood shrubs. This condition usually involves several factors, including poor planting conditions and improper cultural practices, as well as stem and root diseases.

Brown, Spotted, or Patch Grass on Lawn

Thatch

Thatch is a dense buildup of grass stems, roots and blades that accumulates between the leaf blade base and the surface of the soil.

Leaf or Needle Discoloration

Thrips

Thrips are very small yellow-brown or black insects commonly found on flowers in summertime. They feed on a plants’ leaves and flowers by scraping away the epidermal cells and draining the sap.

Pest And Disease Ash Whiteflies Banner 1440X500

Leaf or Needle Discoloration

Whitefly

Although they look like miniature white moths, whiteflies are neither moths nor flies. Instead, they are insects of varying species in the order of Homoptera, which also includes aphids, scales, and mealybugs.

Mold or Fungus

Cytospora Canker

The plant pathogenic fungus Leucostoma kunzei (formerly Valsa kunzei) is the causal agent of cytospora canker, a disease of some conifers found in the Northern Hemisphere, predominantly on Norway spruce (Picea abies) and Colorado blue spruce (Picea pungens).

Mold or Fungus

Fairy Rings

Signs of fairy ring include a dark green circle or arc of rapidly growing turfgrasses, sometimes lined with a band of dead grass. Occasionally, mushrooms or puffballs form along the ring. Fairy rings develop most commonly in spring and fall when there is excess moisture.

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