Fruit IPM Fact Sheet Van Buren MSUE Home
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Fruit IPM Fact Sheet
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Fruittree Leafroller
"Common Tree Fruit Pests":
By: Angus H. Howitt
Scientific Name-
Archips argyrospila
Family-Tortricidae
This insect was first described about 1870. It damaged cherries and apples in Colorado as early as 1891 and was considered a major pest in most fruit-growing regions. With the advent of modern organic pesticides, it has since dropped in status to a minor pest.
Life Stages
Egg: Eggs are deposited in
dark-colored patches on twigs. Each patch contains approximately 60 eggs. The
eggs are closely placed and covered with a heavy coating, so it is difficult to
distinguish individual eggs.
Larva:
The young larva is about 1 mm long and light green with a very large, black head
and a wide, dark-colored prothorax. The body is sparsely covered with long, slender
hairs somewhat noticeable along the sides. When full grown, the larvae measure from
15 to 25 mm; the head capsule is between 1.5 and 1.9 mm. In general, the body of
the mature larva is light green, the head is black, and the thoracic shield is
dark-colored, at least up to the last molt. Late-instar larvae are very similar to obliquebanded leafroller larvae. They can be distinguished in
the field by their vigorous wriggling when disturbed.
Pupa: The pupa is light brown and usually about 10 mm long. It is very active and wiggles vigorously when handled. There are two transverse rows of backward-projecting hooks on the upper side of most of the abdominal segments. The last segment of the abdomen, which is considerably longer than the others, tapers and ends in six strong, chitinous hooks.
Adult:
Wing span ranges from 19 to 23 mm for female moths and 14 to 19 mm for male moths.
The front wings are rusty brown marked with silver-gray or pale gold, which usually forms
two large patches on the front margin of each wing.
Host Range
This pest attacks all kinds of fruit trees and some shade and forest trees. The fruittree leafroller is most troublesome on apples and pears, but it occasionally attacks plums, cherries, peaches and apricots.
It is found in all apple-growing areas of Canada and the United States.
Injury or Damage
After hatching, the young larvae chew into opening buds and mine, often destroying many of them before they open. Newly emerged larvae may make their way down between the buds in the clusters and chew into tiny stems and buds. Such injuries weaken the fruit so that even if flowers are fertilizer, the fruit will drop. Just before the blossoms, open, larvae may make their way inside and web the petals together so that they are unable to open and fertilization cannot occur. At petal fall, the half-grown larvae chew into newly set fruit. The more seriously injured fruit will drop; those that remain on the trees to harvest heal over with depressed russet scars similar to those caused by the obliquebanded leafroller. As the season progresses, the larvae confine their feeding to the foliage and cause some degree of defoliation.
Factors Affecting Abundance
This pest has a wide range of host plants, including many species of wild and cultivated trees.
Life
History
The fruittree leafroller passes winter in the egg stage. Eggs are laid in small, brown, oval clusters about 6 mm in diameter. The clusters are situated on the upper and lateral branches of the twigs and small branches. The eggs hatch in spring about the time the apple leaf buds have opened. The tiny larvae immediately work their way into the opening buds and feed on the inner parts, often retarding the opening of the laves by fastening them together with silken threads.
They attack the fruit buds in the same way and web together and destroy the opening blossoms. On the open leaves, they fold one edge over and fasten it with silken threads, hence the name "leafrollers". The larvae hide inside the rolled leaves, sometimes feeding on the rolled leaves and sometimes coming out to feed on other leaves and on the fruit. Fruittree leafroller larvae look very similar to those of obliquebanded leafroller but are much more active when disturbed.
About the time the apples average 17 mm in diameter, most of the larvae are full grown and have begun to pupate. This takes place mostly inside the rolled leaves, though many pupae may also be found on the ground among the weeds and grass. In uncultivated or weedy orchards, many larvae drop by silken threads to the ground and complete their development on whatever succulent plants they find there.
In about two weeks, the moths begin to emerge and soon start laying eggs. The time of egg laying varies with the season, but on the average, it occurs during the latter half of June. The moths hide during the day, darting away in a zigzag manner if disturbed. They fly around late in the evening and at night. The eggs remain on the trees until the following spring. There is only one generation per year.
Monitoring
Examine buds in the tight cluster/pre-pink stage for evidence of light green larvae with large black heads chewing into opening buds and down between the buds in the fruit clusters. Pheromone traps set out in late May to mid-June will indicate the pests' relative abundance in the area.
Control
The normal cover sprays control this pest.
