Michigan apples advice from MSU

Obliquebanded leafroller - Choristoneura rosaceana (Harris)

There are two complete generations per year in Michigan. Overwintering larvae feed inside bud clusters prior to bloom, begin feeding on fruit after petal fall, and mature in late May and June. Summer larvae are present from about late June into August. A degree day model can be used to predict larval activity periods.


Continuous feeding pattern of summer OBLR larvae.	An egg mass on a leaf.


Wings of the adult are banded with tan to brown scales. Adults are about 18-25 mm long.	Larvae are green with brown to black head capsules (about 25 mm long at maturity).

Suggested monitoring and thresholds: Check for overwintering survivors in terminals after petal fall. If larvae are found in more than 1-2% of the shoots, summer controls likely will be needed. Use one pheromone trap per 15 or 20 acres to set biofix and as an indicator of leaf-roller activity. Lures are highly attractive and gen-erally last a generation. Traps tend to capture a lot of moths making it difficult to use them for decision making. However, a consistent catch of 20 plus moths for 2-3 weeks usually indicates a problem. Very low catches of less than 20 moths for an entire flight period generally means this pest is not present at problematic levels.

View current Michigan growing degree day accumulations at Enviro-weather. Select a weather station from the map that is closest to your location. Then click on "fruit" for a list of weather resources and models for fruit production.

Obliquebanded leafroller growing degree day table

Additional information

For more monitoring information and evaluation of available pesticides:
Michigan Fruit Management Guide
A Practical Guide to Scouting Apple Orchards – a DVD showing how to scout apple orchards.
MSU Diagnostic Services for assistance in pest identification.
MSU Fruit Crop Advisory Team Alert newsletters for current pest/crop conditions.

This information was developed from A Pocket Guide for IPM Scouting in Michigan Apples by David Epstein, Larry J. Gut and George W. Sundin. Purchase this in a pocket-sized guide for reference in the orchard from MSU Extension (publication E-2720).