HOW to
How to Distinguish Oak LEAFTIERS From LEAFROLLERS
HOW to footer

Introduction
What are Leaftiers and Leafrollers?
Leaf webbing habits
Larval characteristics
Important leaftiers and leaferollers on oak
Author
horizontal ruler
Figure 1. Oak trees defoliated by oak leaftier.
Figure 1. Oak trees defoliated by oak leaftier.
Introduction
Oak leaftiers and oak leafrollers defoliate oaks throughout the northeastern United States and adjoining Canadian provinces.

In recent years, scattered but severe outbreaks of oak Leaftier have occurred in Connecticut, Massachusetts, New Jersey, New York, Pennsylvania, and West Virginia. In 1978 more than 100,000 acres were defoliated in these states. Outbreaks of the oak leafroller complex have been reported in Michigan, Pennsylvania, and West Virginia.

Two or more years of moderate to severe defoliation by tiers and rollers usually results in twig and branch dieback, loss of diameter growth, and tree decline (Figure 1). Tree mortality has occurred in many areas. Trees with half of the twigs and branches dead are often subsequently attacked by wood borers. especially the twolined chestnut borer, Agrilus bilineatus (Weber), and the shoestring root fungus, Armillariella mellea Vahl. ex Fr.

What are Leaftiers and Leafrollers?
Although oak leaftiers and leafrollers resemble each other in the larval stages, the two insects differ in the way they web leaves and in larval characteristics.

Figure 2. A leaf rolled by a leafroller.
Figure 2. A leaf rolled by a leafroller.
Leaf webbing habits
The leaftier larva (caterpillar) binds two or more leaves together with strands of silk and then feeds and rests between them. The larva is found by separating the tied leaves (cover photo). After feeding ceases, the larva drops to the ground and pupates in the litter or duff. The leaftiers of oak include a small group of tortricid moths and three other minor families

The leafroller larva rolls or folds one leaf, then binds it with strands of silk. It feeds and rests within the rolled or folded leaf (Figure 2). The larva is found by unrolling the partially folded leaf. Although some larvae may pupate in folded leaves, most pupate on the ground. The leafrollers of oak are comprised of more than 15 species of moths in 5 families. Of these, about 60 percent are tortricid moths.
Larval characteristics
Oak Leaftiers
Head: Both, dark area around the eye and a broad dark brown to black bar on side of head always present Figure 3).

Prothorax (front of thorax): Legs dark brown to black. (Figure 3)

Oak Leafrollers
Head: Either dark area around the eye or broad dark bar on side of head, or neither present; never both. (Figure 4)

Prothorax (front of thorax): Legs not dark brown to black. (Figure 4)
Figure 3. Head and portion of body of oak leaftier larva.
Figure 3. Head and portion of body of oak leaftier larva, Croesia semipurpurana (Kearfott). Dark area around the eye and a broad dark brown to black bar on side of head; legs dark. (Magnification 150X).
Figure 4.-Head and portion of last larval instar of oak leafroller
Figure 4. Head and portion of last larval instar of oak leafroller, Archips semiferanus (Walker). Either dark area around the eye or broad dark bar on side of head, or neither present; legs not dark. (Other larval instars of this species have black heads and prothoracic shields.) (Magnification 150X)
Important leaftiers and leafrollers on oak
An important oak leaftier is Croesia semipurpurana (Kearfott). The larva of C. semipurpurana is an early defoliator of northern red oak, black oak, pin oak, scarlet oak, and scrub oak (Figure 5). It feeds on unopened buds and developing foliage in early spring, resulting in severe stress on food reserves. Rarely are chestnut and white oak attacked.

The most important oak leafroller is Archips semiferanus (Walker) (Figure 6). Other leafrollers of oak such as A. argyrosplilus (Wlkr.) and Choristoneura fractivittana (Clem.) are not known to cause serious damage but are abundant on oak and feed with A. semiferanus and C. semipurpurana. Most leafroller larvae hatch about a week later than oak Leaftier larvae. This group of insects may also feed on other hardwoods.
Figure 5. Larva of oak leaftier, C. semipurpurana.
Figure 5. Larva of oak leaftier, C. semipurpurana.
Figure 6. Last larval instar of oak leafroller, A. semiferanus. (Other larval instars of this species have black heads and prothoracic shields.)
Figure 6. Last larval instar of oak leafroller, A. semiferanus. (Other larval instars of this species have black heads and prothoracic shields.)
Author
Parker Snowden, Entomologist
NA State and Private Forestry
Portsmouth, NH 03801

December 1990
horizontal ruler
TOP..........