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IPM Message for Cranberry Growers: May 28, 2021

May 28, 2021

Sprays have been going out to manage green spanworm and cranberry weevil. Avaunt has been very effective in most cases, but reports of lower efficacy have been heard.

Bogs are in full roughneck especially in warmer areas with a few hooks here and there.  If you are using slow or controlled release fertilizers, 50-100% of your N dose goes out now (if you do not use 100%, apply the balance at set).  Fast-acting soluble fertilizer would be about 20% at roughneck to hook.  Bogs that held late water floods can typically skip the first N dose.

Use of pheromone traps will help you time your insecticide sprays for Spag, girdler and black-headed fireworm.  They should be set out by June 1.  Use 1 trap per 10 acres.  Place on the upwind side of the bog.  Traps should be checked weekly; write down the number of moths captured.  The bait should be changed every 3 weeks. 

Fungicide applications to protect against fruit rot can start early to mid-bloom (still have probably 10-14 days in most locations). If you are considering broad-spectrum fungicides such as Chlorothalonils (e.g., Bravo Weather Stik and Bravo Ultrex) and Mancozebs (e.g., Manzate Max, Dithane M-45) as part of fungicide regimes, use them when the maximum number of flowers are open: early to mid-bloom).

Applications of grass herbicides should be made when grasses are 4-8 inches tall and prior to bloom.  You can make multiple applications with all of the grass herbicides.  This will help you target/manage early, mid and late season grasses. Be sure to include an adjuvant with all POST herbicide applications.  Intensity One is the only grass herbicide that can be chemigated.  A grower reported good moss control with 2 consecutive years of applications of Zeus with little to no vine injury; they anticipate the moss control to be good to excellent in locations where the moss infestation was light to moderate.  Callisto (chemigated or spot applications) can be used to control poison ivy.  Make sure the leaves are fully expanded before applying.  You want to have the most leaf surface possible to maximize herbicide activity.

We will be hosting a lunchtime Bogside on June 9, noon-1.  Contact Robyn at the station for more information and the link.