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IPM Message for Cranberry Growers: Jul 15, 2010

July 15, 2010

From the Entomology Lab: Keep in mind that Belay is only being recommended for cranberry weevil; it is a better choice than Actara for weevil management. Black-headed fireworm, cranberry fruitworm and Spag are on the Belay label but will likely only suppress at the 4 oz rate. Fruitworm are showing up at low levels at many beds and lots of red berries on some Stevens beds where fruitworm sprays went out too late.

Reminder for those delivering to Ocean Spray: No Sevin (carbaryl) applications can be made after August 1. Delegate is looking great for cranberry fruitworm control but you can only apply a total of 19.5 oz/A per season. Black headed fireworm is still showing up and there have been a few Southern Red Mite reports here and there.

There has been some talk about a combination spray of Callisto, Poast and crop oil that seems to be controlling poison ivy. Based on the mode of action of Poast, it is only effective against grasses. Broadleaved plants, like poison ivy, are naturally resistant to herbicides like Poast because they have do not have the enzyme that is affected by the herbicide’s active ingredient. So, there is no straightforward reason to believe Poast is helping here unless one of its inert ingredients is doing something (this is very unlikely).

I suspect it is the high rates of Callisto that are producing the control of the poison ivy. Keep in mind, to apply the equivalent of the highest label rate of Callisto (8 oz/A), use just 1.6 tsp per gallon (this assumes an application rate of 30 gallons of water per acre, which is very reasonable for most ground applicators); 1.6 tsp equivalent to about 0.27 oz. The maximum amount of NIS should be 1.9 tsp (0.32 oz) per gallon or 2.5 TBsp (1.3 oz) crop oil; you can use about 2 oz of Poast per gallon of water to deliver the high-end rate of a 1.5% solution. If this combination is working and there are no application issues, then this is good news. Just be sure your recipe keeps to the rates permitted by the label.