Redbanded Leafroller

This is a native pest. Redbanded Leafroller was first reported on grapes in 1870 and on apples in 1879. It caused little or no damage on apples until about 1918.

Life Stages
Egg: The eggs are cemented together in patches on masses. Some egg masses contain as few as three or four eggs, while others contain as many as 145. These egg patches are usually oval in outline and vary from 1.6 to 6 mm in width. The pale yellowish or cream-colored masses resemble spots of tallow. the individual egg is a pale, flat disk about 0.8 mm in diameter. Upon close examination, the eggs will appear as overlapping scales in the mass. On apple trees, first-brood eggs are laid on the bark, chiefly on the trunk and scaffold limbs. Eggs of the second brook are laid mostly on upper leaf surfaces.

Larva: The larval stage is pale-headed, greenish, active caterpillar that measures about 16 mm long at maturity. When newly hatched, the larva is bright yellow and about 1.6 mm long. After it has fed, the body of the new caterpillar turns green and thereafter ranges from a pale, dull yellowish green to a bright apple green, depending on the kind of food consumed. The head and thoracic shield are pale straw-colored or the same color as the body. In contrast, the larval stage of the fruit tree leafroller has a dark brown or black head capsule.

Pupa: The pupa ranges in color from light brown, sometimes with tinges of green, to deep brown, and measures from 7 to 8 mm long. The larger pupae usually produce female moths.

Adult: Moth wing spans are 12 to 18 mm. The overall color is reddish brown, relieved by lighter markings of silver-gray and orange. Though the pattern of the markings varies considerably, a fairly distinct, wide, reddish brown band extends across the forewings, giving rise to the common name of the pest. The male is usually smaller and more active than the female. Male wing spans are 12 to 15 mm, while female wing spans measure 14 to 18 mm.

The redbanded leafroller is a general feeder--the larvae have been found feeding on a large number of unrelated plants, including most common fruits, vegetables, weeds, flowers, ornamentals and shrubs. Among the fruits the leafroller shows a strong preference for apples. It is common in the apple-growing areas of the midwestern and eastern United States and eastern and western Canada. It has also damaged plums, grapes, peaches, raspberries, strawberries and cherries.

The redbanded leafroller injures both foliage and fruit. The injury tot he foliage is of little significance except when infestations are extremely high. The larvae skeletonize leaves from the underside, folding and webbing the leaves together.

Infestations in non-bearing trees have not been heavy enough to constitute a problem. Injury to fruit is the main concern to the grower. First-brood larvae feed on apples in June and early July when the fruits are small, making irregular, shallow cavities in the fruit. Feeding may occur at the point where two or more fruits touch. A single larva may eat a considerable area. Some of these young fruits may be so severely damaged that they do not survive. The injured areas gradually cork over, and the apples usually develop into deformed or misshapen culls.

First-brood injury is distinguishable from that of the fruit tree leafroller and oblique-banded leafroller, which occurs earlier and is deeper, so that by harvest, there is a deep depression with gradually rounding edges. The injured surface is usually rough and russetted. Redbanded leafroller injury is usually shallower and often is characterized by ragged edges and thick, corky tissue over the damaged area. Injury by second- and third-brood redbanded leafroller larvae occurs where a leaf is webbed to an apple or where apples are present in a cluster.

Other points favored for feeding include the depressions at the stem and calyx ends of the fruit. The larvae eat the skin and the flesh immediately beneath. Feeding areas are shallow and irregular and may be of considerable size, particularly when several larvae feed on one fruit.

Second- and third-brood injury occurs so late in the season that the fruits--except possible hard winter varieties--are incapable of corking over the wounded tissue. Usually however, second- and third-brood feeding areas are sources of infection for various rots and allow rapid moisture losses. Injured apples do not store well. When a high percentage of crop is affected, it has been found impractical to sort out the uninjured apples. Consequently, whole crops have been abandoned. Injured fruits in heavy infestations tend to fall before the normal harvest time.

Before 1946 and the introduction of DDT, the redbanded leafroller was generally rated as a minor pest. DDT killed many of its parasites and predators, and the redbanded leafroller abruptly became a major pest. It is now an apple pest in the principal fruit-growing districts of the midwestern and eastern United States. In past years, failure to control the first generation could result in damaging numbers in the second and third generations, when coverage is more difficult because of dense foliage. Currently, redbanded leafroller is again a minor pest. It has largely been replaced pesticide-resistant strains of obliquebanded leafroller.

In the north central states, the redbanded leafroller usually produces two broods, and in many years a partial third brood develops. The insect overwinters as a pupa on the ground, in the leaves and other debris under the trees. Moths emerge in the spring soon after the first green tissue shows in the buds. They may be found until after bloom, but the greatest numbers are present in the late delayed dormant to pink bud stages. Moths are commonly found resting on the trunks and main scaffold limbs of the trees. In cold, windy weather, the moths are inactive and are usually found on the sheltered side of the trees. They fly only short distances when disturbed. Moths are most active on warm days, particularly in the afternoon.

First-brood moths are found in the lower parts of the tree, while second-brood moths are found in all parts of the tree. they seem to like bright sunshine and avoid the shaded lower inside of thick trees. Moths begin laying eggs shortly after emerging, so the first eggs may appear in the delayed dormant and early preblossom period. Egg deposition may be heavy in outbreak years. First-brood egg masses are laid mostly on the bark, chiefly on the trunks and main scaffold limbs. The exact position appears to be influenced by weather conditions. Hatching usually coincides with the middle to the end of bloom for the McIntosh variety.

First-brood larvae crawl along the trunks and limbs until they reach the leaves. They feed on the undersurface along the midrib or along one of the larger veins. Each larva spins a flimsy white web that it expands as the larva grows. The clean, white webbing of redbanded leafroller larvae is easily distinguished from that of the eyespotted apple bud moth, which is active at this same time. Bud moth webbing is stained and littered with frass, and the larvae are dark brown rather than green. First-brood larvae reach maturity mostly during the first half of July, though a few mature earlier and others considerably later. When the larvae are about half grown, they may migrate to and feed on the fruit, though some individuals complete development on the leaves. The larvae pupate in a sheltered site, such as inside a rolled leaf or between leaves on which they have fed. Pupation may also take place in holes the larva had eaten earlier into the young fruit. The pupal stage lasts from 10 to 14 days.

Moths of the second brood begin to lay eggs shortly after emergence and continue until August. These eggs are laid mostly on the upper surfaces of the leaves and are difficult to find. Second-brood larvae feed on the undersides of the leaves, where they feed and make webbing until partially grown. Near the end of August, the larvae move around in the tree and may feed on the fruit or web leaves together and feed there. Damage to fruit may continue into October. Larvae pupate in the debris on the ground in October. There may be a partial third brood.

Because of a wide host range, pheromone traps, if employed as the sole indicator, are unreliable for indicating whether sprays are needed.

Using 45 degrees F as a base, degree-days (DD) for redbanded leafroller activity* are:

50 DD	first adult emergence.
125 DD	first eggs laid.
200 DD	peak adult emergence
350 DD	peak egg laying by first-generation adults
700 DD	first emergence of second generation adults
850 DD	first eggs laid by second-generation adults
1,125 DD	peak emergence of second-generation adults
1,300 DD	peak egg laying by second-generation adults
1,700 DD	first emergence of third-generation adults
1,800	first eggs laid by third-generation adults

When infestations are severe, sprays applied at the delayed dormant stage will control the adults before the female lays eggs, thus greatly reducing the amount of egg laying. Normally, these eggs begin to hatch at petal fall, so broad spectrum sprays applied at petal fall will control this pest. Because the redbanded leafroller has so many host plants, pheromone traps may be useful in determining the occurrence of generations, but they have limited value in determining economic thresholds. When redbanded leafroller is a problem, it is essential to control the first generation. Large numbers of surviving first-generation redbanded leafrollers can create problem populations in the second and third generations. Inspect orchards for larvae and feeding from the first generation to determine the need for second generation sprays. Renew pheromone traps and caps to time sprays, based on trap catches, for adults of the second and a possible third generation.

Created: November 16, 1998