Defoliatorsdefinition:adult or larval insect that strips all the leaves from a tree or shrub

Characteristics

pattern on individual leaves “shot hole” “leaf mines” “skeleton” structures that they create from which to feed time of the growing season that feeding occurs

Non-outbreak: areas where no defoliation is noticed in aerial overviews, and insect numbers are low. Building phase: when insect populations increase, yet very little or no defoliation is visible from aerial surveys. Outbreak phase: the time period when defoliating insects are causing noticeable damage. Declining phase: the time interval when areas of defoliation and insect numbers decline and large amounts of damaged trees are visible.

Phases

Ancylis apicana

Leaf-folder where larvae connect silk to two sides of a leaf and pull them together into the folded position. Although its range is identified as across the northern United States and adjacent Canada, it was only identified from Washington in 2009.

Apple-and-thorn skeletonizer

A widespread native defoliator moth that feeds on apple, cherry, birch, hawthorn, willow, and mountain ash. Multiple generations per year create distinctive skeletonized leaves by eating only the surface of leaves and webbing leaves into a cup shape.

Epinotia albangulana

A native and common defoliator that feeds alder trees. Found from California to British Columbia and Idaho. One generation per year.

Fall Webworm

Native web-making species. During outbreak years commonly seen in wide variety of fruit and deciduous. One generation per year.

Oblique-banded leafroller

Native defoliator. Most commonly on fruit trees in eastern and western Washington and Idaho. Two generations per year and overwinters as larvae.

Orange tortrix

Native species common at times on a large list of fruit trees. Two generations per year and overwinters as larvae.

Oreana unicolorella

Oreana unicolorella is found across the northern United States and southeastern Canada. This leaf roller has a wide host range, including apple, birch, elm, willow, and maple.

Silver-spotted tiger moth

The most common native web-making species in conifers in the North West region. Larva overwinter in small tents, which grow to visibility in spring.

Tent caterpillar

One of several native tent-making species in the North West. Various species feed on fruit trees, ornamentals and native trees. Most feed as a group in tents. One generation per year, overwinter in egg stage.

Sources•Barrett, Bruce . “Insect Defoliators of Missouri Trees: Web Producers.” 2012. extension.missouri.edu. 25 November 2012. Web.•Moorhead, D.J. “Forest Pest Control.” 2012. www.bugwood.org/. 25 November 2012. Web.•http://cfs.nrcan.gc.ca/publications/?id=1624•http://www.google.com/url?sa=t&rct=j&q=&•http://www.google.com/url?sa=t&rct=j&q=&