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Apple Clearwing Moth - Trunk Sprays

Saturday May 25, 2024

Apple Cl(ear Wing Moth (photo G. Judd)

Apple Clearwing Moth (Synanthedon myopaeformis) - Trunk Spray timing is happening now. 

Trunk Sprays are one of the most effective applications that can be made against the invasive pest - Apple Clearwing Moth. Time the application to target the larva, starting at 150 DDC and aiming to complete the application by 200 DDC. Growers  - you can use the degree days the Codling Moth model on BCDAS to time your trunk spray. 

Apply 1.4 L Rimon per 1000 liters of water in a high volume spray (maximum 800 liter/acre). Field research has demonstrated that high volume gun sprays are the most effective means of spraying trunks. Organic growers can use Entrust. 

Scout your blocks for ACWM by scanning the trunks of apple trees for signs of the emergence of reddish brown frass from entry holes. The frass may also be found in aerial roots,pruning scars, branch collars and grafts. Tree tops and pruning wounds in the crown can also be infested. Pay particular attention to weak trees or those trees showing symptoms of decline.

Local research by Dr. Gary Judd and consultants Linda Edwards and Tamara Richardson has demonstrated that trunk sprays with Rimon (Entrust - for Organic production) are probably the single most effective application to control ACWM. Rimon will kill larva already present in the tree.

Additional summer sprays (Entrust, Delegate, Altacor, AltacorMAX, Success) should be used to prevent new damage in young blocks. Two Apple Clearwing Moth sprays are recommended be applied at 550 and 850 Degree Days, based on the BCDAS Codling Moth DD. Local experience indicates that the Codling moth degree day model works for ACWM when daytime temperatures stay below 30°C.