Northwest berry Foundation

Management Detail

Leafroller, Orange tortrix

in Blueberries

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Latin name: Argyrotaenia franciscana

Description:

Reason for Concern:
1) Leafroller larvae chew on buds, flower parts, and leaves. Damage is considered negligible on mature plants.
2) Stunting and undesirable branching can occur on young plants when growing points are eaten.
3) The larvae also feed on early fruit clusters from late April through early June.
4) During harvest, larvae fall into picking pails or onto harvesting belts, contaminating fruit.

Identification/Symptoms:
The adult orange tortrix moth is orange, about ½- to ¾-inch long, and bell-shaped when at rest. Larvae are tan when small, changing to pale green with tan heads as they mature (reaching a size of up to 12 mm). The adult obliquebanded leafroller moth is about ¾-inch long, bell-shaped when at rest, and has diagonal bands across its forewings. The larvae are tan when small, changing to leaf-green with black heads as they mature (reaching a size of up to 12 mm). Eggs appear as greenish masses on leaves, with up to 150 eggs per site. In June and July, when leafrollers are present, leaves will be rolled and tied together or tied to the fruit with silk.

Lifecycle:
Leafrollers overwinter as eggs under loose bark, or as pupae in the litter under the bushes or as small larvae. If the winter is warm, they will remain active and feed on cane buds. Normally, larvae become active in March or April. The moths occur as early as February. The obliquebanded leafroller has 2 generations each year; the orange tortrix has 2 to 3 generations per year.

Links:


Scouting:

  • This is a minor blueberry pest but in mild winters, check blueberry buds for potential damage from OT larval feeding.
  • Place pheromone traps in fields beginning in late April or May and check weekly. Change lures every 28 days and trap bottoms when debris (organic material) limits the usefulness of the trap. Count and record. Scrape trap bottom and note date on trap when bottoms and lures are changed.
  • As the pheromone attractant for Orange Tortrix and Obliquebanded Tortrix is very similar, it is necessary to distinguish between the two while trapping. Orange Tortrix is considerably smaller than the Obliquebanded, and the Obliquebanded generally has much thicker, more pronounced, diagonal lines across its wings. Carnation Tortrix will also sometimes be caught and is easily discernible by its bright orange coloring on the underside of its wings.
  • About a week after peak flight, begin scouting for larvae. The Orange Tortrix larva will appear light brown to yellow green, and will appear full grown at ¾” (2-3cm) long. When agitated, it will wiggle vigorously backwards and drop to the ground on a silken thread. Orange Tortrix larvae differ from Obliquebanded larvae in that the Orange Tortix larvae will have a much lighter colored head than Obliquebanded which has a brown or black head.
  • Search 10 leaf tips in at least 4 areas of the field for indication of larvae (rolled leaf often at tip of canes). Identify, record number and destroy. Change areas per visit in order to cover field.
  • Leafrollers are a minor pest in blueberries, however, there may be low tolerances for blueberry exports to certain countries.

 
Cultural Controls:

  • Pheromone traps can be used to monitor male moth flight in spring to determine the potential of the moth to be a contaminant. Unless field has shown prior problems with Orange Tortrix, this is not needed.

 

For information about chemical controls, check with our Pesticide Guide.

images


Leafroller in blueberry bud - photo by T. Peerbolt


photo by T. Peerbolt

 


photo by K. Gray


The black head of the leafroller is all that is left beside the cacoon of the parisitoid - photo by T. Peerbolt

 


Not OT. This is the typical triangle learoll made by a Pyramid Leafroller occasionally found in blueberries (not a pest insect) - photo by T. Peerbolt


OT larva found in blueberries - photo by T. Peerbolt

 


OT larva - photo by T. Murray


OT larva found in blueberries - photo by T. Peerbolt

 

 

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© 2016

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