What are they?
There are several exotic leafrollers of concern that are present in Washington. Some of these species include the Apple Tortrix, Apricot Moth (Ditula angustiorana), Garden Rose Tortrix (Acleris variegana), Green Budworm (Hedya nubiferana), Barred Fruit Tree Tortrix (Pandemis cerasana), European Fruit Tree Tortrix Moth (Archips podana), Dark Fruit Tree Tortrix (Pandemis heparama), European Leafroller (Archips rosanus), and the Carnation Tortrix (Cacoecimorpha pronubana). Exotic leafrollers are pests of fruit trees and ornamentals. They damage trees by rolling and eating leaves, conifer needles, and shrubs. The name leafroller comes from the larvae's habit of rolling or tying leaves together when building feeding sites or shelters.
Are they here yet?
Yes. These species all can be found in Washington. Many of them were introduced to our state in the 1970s, others were introduced as recently as 1995.
Why should I care?
Exotic leafrollers cause considerable damage to tree and shrub leaves. In addition to feeding on foliage, leafrollers injure trees by pruning leaves, flower parts, or fruit to construct shelters in which they live. When they are abundant, leafrollers can defoliate fruit trees completely.
What should I do if I find one?
How can we stop them?
Do not transport infested plant or tree materials to non-infested areas. Please contact the Washington State Department of Agriculture or your local Washington State University Extension office for specific management approaches or prevention techniques. Some approaches may include removing host trees or pruning infested parts of the tree. The Washington State Department of Agriculture and other organizations have ongoing surveys and traps set up to monitor spread and plan control of these species.
What are their characteristics?
- Defoliators pass through four main life stages; eggs, larva (caterpillar), pupa, and adult.
- In the early larva stage, most defoliators are a light green with a dark head. As they grow, colors and patterns develop, which make them easier to identify.
- It is during larval development that the larva roll, twist, fold, or wad leaves for protection from predators. Next, the larva will form a pupa in the leaf shelter they've constructed.
- The adult defoliator emerges from the pupa within two to three weeks.
For identification of these varied species, contact your local Washington State University Extension office or master gardener. Also visit the links below for additional images and identification resources.
How do I distinguish them from native species?
For identification of these varied species, contact your local Washington State University Extension office or master gardener. Also, visit the links below for additional images and identification resources.
Where can I get more information?
- Natural Resources Canada - red-barred tortrix
- National Agricultural Pest Information System - apple tortrix
- University of Iowa's BugGuide - apricot moth
- Washington Department of Agriculture - Species of Concern
- Washington State University, Clark County Extension - leafrollers
- Washington State University, Entomology - leafrollers
- Washington State University - defoliators
- Washington State University – Tree fruit research and extension