Lynn E. Long Horticulture Extension Agent Oregon State University Wasco County Extension

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Monitoring Obliquebanded Leafroller in
Sweet Cherry Orchards

Contents
      OBLR Life History
      Strategies for Controlling OBLR
      Delayed Dormant Bloom
      Trapping Adult Moth
      Scouting Method
      Monitoring Overwintering Larvae
      Monitoring Summer Generation

OBLR Adults

OBLR Life History

The obliquebanded leafroller (OBLR) is a pest of sweet cherries throughout North America. The larvae feed primarily on foliage but can infest fruit and contaminate bins, causing fruit to be rejected by the packing house.

OBLR overwinter as small larvae and begin emerging with the first bud swell in late March. These larvae are known as the overwintering generation. Most larvae in the orchard have emerged by bud stage 4 (tight cluster). These larvae mature to the adult stage and begin the first adult flight in mid-May. Eggs from the first flight hatch during Royal Anne harvest beginning the summer generation. the larvae of the summer generation infest fruit and mature throughout harvest. The second adult flight begins in late summer. The offspring produced by second flight adults hibernate and emerge next spring to repeat the cycle.

Strategies for Controlling OBLR

Diligence prior to and during the growing season is the key to controlling OBLR.  By paying close attention to the following points, control is possible.

• Proper sprayer calibration is critical. Call your fieldman for help.
• Adjust sprayer to give better coverage towards the bottom third of tree. Be sure to cover root suckers.
• Spray penetration to the tree center is critical:
      Þ Do not spray in wind.
       Þ Tractor speeds should be 2 mph or less.
       Þ Apply insecticide with a minimum of 200 gallons of water per acre.
       Þ Remove suckers for better spray penetration.
• Do not skimp on chemical rates to save money.
• Proper timing of spray is critical. This is especially true for Bacillus thuringiensis (Bt.). Spray Bt. only when daytime temperature equals or exceeds 60°F and rain is not expected for four days.