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Beginner

Scientific Name: Choristoneura rosaceana (Olethreutes permundana and Argyrotaenia citrana) (Order: Lepidoptera, Family: Tortricidae)

Identification

• Several species of leafrollers can affect raspberries: obliquebanded leafroller, Choristoneura rosaceana, most common found on Ontario raspberries; orange tortrix, Argyrotaenia citrana, less common; and raspberry leafroller, Olethreutes permundana, less common.
• Obliquebanded leafroller adults are orange-beige moths with oblique wing banding on the forewings.
• When resting with wings folded, moths have a bell shape, when wings are unfolded moths are approx. 25 mm-30 mm wide.
• Larvae are green with a dark brown or black head and legs and a black stripe across their prothorax.
• Larvae measure up to 30 mm when mature, and wriggle actively when disturbed.
• Leafroller larvae web together terminal leaves of raspberries, rolling them up to create a cavity where they pupate.
• Pupae are deep brown and measure between 10 and 13 mm. Empty pupal cases are often observed in webbed up leaves.

Often Confused With
Spiders
Sawfly larvae

Period of Activity
The development of this pest is very sporadic and many stages of development may be present at once. Overwintering larvae feed on raspberry buds and foliage in late April and throughout May. Adults are present from early June until August. The first summer generation of larvae hatch in late June and are present on raspberry leaves in July and August. Second generation larvae are present in late summer and fall, but they do very little damage to raspberries. In fall, they enter diapause and overwinter in rolled-up leaves to emerge again in the spring.

Scouting Notes
Focus scouting in areas where raspberries are harvested by machine, rather than by hand, because larvae are shaken off with the harvested berries and contaminate the harvested product.

Scouts should watch for leafroller larvae in spring and summer. Look on growing terminals and shoots for rolled up leaves with webbing and larvae inside. The most serious damage occurs if larvae are numerous before harvest. Problems are more likely to develop in modified climates (high tunnels or greenhouses) and fall fruiting varieties, if high populations of larvae coincide with fruit bud development or harvest.

Thresholds
Not established.

 

Advanced

Scientific Name: Choristoneura rosaceana (Olethreutes permundana and Argyrotaenia citrana) (Order: Lepidoptera, Family: Tortricidae)

Identification
Several species of leafrollers can affect raspberries.
The obliquebanded leafroller, Choristoneura rosaceana, is the most common leafroller found on Ontario raspberries. The orange tortrix, Argyrotaenia citrana, and the raspberry leafroller, Olethreutes permundana, are less common.

Obliquebanded leafroller adults are orange-beige moths with oblique wing banding on the forewings. When resting with wings folded, moths have a bell shape. Unfolded, the wingspan is between 16 to 25 mm for males and 23 to 30 mm for females. The hind wing is usually a lighter colour with a fringe at the outer edge.

Larvae are green with a dark brown or black head and legs and a black stripe across their prothorax. Early instar larvae have a black head capsule, while head capsule of 5th and 6th instar larvae is dark brown. Larvae measure up to 30 mm when mature, and wriggle actively when disturbed. Leafroller larvae web together terminal leaves of raspberries, rolling them up to create a cavity where they pupate. Pupae are deep brown and measure between 10 and 13 mm. Empty pupal cases are often observed in webbed up leaves.

Often Confused With
Spiders
The webbing of a spider inside a curled up leaf can sometimes be confused with leafroller damage.

Sawfly Larvae
Sawfly larvae have spiny projections on their bodies that give them a furry look. Sawfly larvae can be distinguished from leafroller larvae by the number of prolegs, or fleshy, leg-like projections that follow the three pairs of true legs on the front. Sawflies have 5 or more prolegs, while leafroller larvae, and all larvae in the moth/butterfly family, have less than 5 pairs of prolegs.

Biology
The obliquebanded leafroller usually has two generations a year but may only produce one generation in northern, cooler climates.

This pest overwinters as second or third instar larvae in webbed and folded over leaves. In spring, larvae become active again, feeding on buds, young leaves, and sometimes flower buds. Pupation occurs in late spring and 1st generation adult moths emerge in late May or early June.
In June, female moths lay egg masses containing up to 900 individual eggs onto the surface of leaves and cover them with a waxy material. After 5 to 14 days, first instar larvae emerge from the eggs and begin to seek shelter under leaves or inside flower buds. They disperse by using silken threads to float in the air. There are six larval instars. Pupae are found within the folded leaf. Adults emerge after 10 to 12 days.

If a second generation is produced, the larvae that hatched in June complete their development the same summer and adults emerge in August. This second generation of adults lay eggs and produce larvae that will enter diapause and overwinter as second or third instar larvae in rolled up leaves.

Period of Activity
The development of this pest is very sporadic and many stages of development may be present at once. Overwintering larvae feed on raspberry buds and foliage in late April and throughout May. Adults are present from early June until August. The first summer generation of larvae hatch in late June and are present on raspberry leaves in July and August. Second generation larvae are present in late summer and fall, but they do very little damage to raspberries. In fall, they enter diapause and overwinter in rolled-up leaves to emerge again in the spring.

Scouting Notes
In Ontario, leafrollers generally cause minor damage to raspberries by feeding on leaves and developing buds. They are kept in check by naturally-occurring predators and parasitic insects, and by insecticides used for other pests. Leafrollers are more important in areas where raspberries are harvested by machine, rather than by hand, because larvae are shaken off with the harvested berries and contaminate the harvested product.

Scouts should watch for leafroller larvae in spring and summer. Look on growing terminals and shoots for rolled up leaves with webbing and larvae inside. The most serious damage occurs if larvae are numerous before harvest. Problems are more likely to develop in modified climates (high tunnels or greenhouses) and fall fruiting varieties, if high populations of larvae coincide with fruit bud development or harvest.

Insecticides for this pest are targeted for very early instars. If sprays are required for leafrollers, use pheromone traps to monitor for adult activity and use growing degree days to predict when early instars will be active. Information on the use of pheromone traps and growing degree days for obliquebanded leafroller is outlined under insect pests for apples. (OMAFRA Apple IPM).

Thresholds
Not established.

Management Notes

• Pheromone traps may be used to trap and count leafroller adults and predict larval emergence, and degree day models can be used to optimize spray timing. (see details in OMAFRA Apple IPM).
• Insecticides are most effective against early instar larvae. Older larvae are difficult to control.
• Remove and destroy old fruiting canes to reduce the number of overwintering shelters available to larvae.
• Leafrollers have many natural enemies and parasitization rates are high. Management practices which encourage beneficial insects will help keep the population of leafrollers below damaging levels. Avoid using insecticides toxic to beneficial insects.