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IPM Message for Cranberry Growers: May 20, 2013

May 20, 2013

Insect populations continue to be low. However, now is the time to sweep!

Winter moth larvae are easily seen in sweep nets at this time. Populations are not nearly as high as expected this year, but it would be wise to check your own bog. Small gypsy moth, false army worm and even black-headed fireworm have been reported on bogs.

Cranberry weevil are active at this point and some pockets over threshold (4.5/25 sweeps) have been found. Remember, grey weevils found in the sweeps should not be counted as they are not a cranberry pest. Avaunt is a good choice if you have both winter moth or other larvae and weevil. If weevil is not in the mix, Delegate is a good choice for the worm pests, as is Intrepid.

Dodder seedlings are germinated everywhere, we are reaching the end of the window for pre-emergence sprays for dodder. Quinstar is now fully registered for both pre- and post-emergence control of dodder. Many handler restrictions are in place for this compound, so make sure of your handler's requirements before using. Also note that the allowed MAXIMUM RATE on the label is 8 oz. per acre per application with a maximum of two applications [the old Section 8 label allowed up to 12 oz. per application - the new label does NOT].

The window for pre-emergence management of other weeds is over. If the weeds are up, time early post-emergence Callisto applications in the next two weeks or so. This material requires 4 hours to be rain fast.

Frost continues to be a concern with all cultivars advanced to at least bud elongation stage. The tolerance for all cultivars is 29.5 degrees Fahrenheit. 

Since we have reached bud break, we reaching the end of the window for fungicide treatments for upright dieback If you had this disease in 2012, consider an application of fungicide following the recommendations in the Chart Book.