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IPM Message for Cranberry Growers: Jun 7, 2013

June 7, 2013

This is the week of spag. There is, however, no easy answer!

Many growers have reported finding Sparganothis larvae in their sweep nets this week. Small, medium, and large larvae have all been reported, as well as the beginning of flight in the pheromone traps (that should be up by now). A few growers reported higher counts of larvae, but most reports were right at or under threshold. Perhaps Avaunt took out all the other caterpillars and now all we find is Spag. It DOES appear to be higher than normal reports. Pheromone trap numbers will go up for the next 3-4 weeks before they start going down! The eggs take 9-12 days to hatch.

The only choices to manage Sparganothis fruitworm are Intrepid, Altacor and Delegate. Intrepid and Altacor will not kill large larvae. They need to be eaten and are best timed against eggs and small larvae. They require good chemigation systems and likely anything over 6-8 minutes will be too watered down to be effective. Several days of good weather are also necessary to maximize effectiveness. Delegate is more likely to take out the medium or larger larvae. We have gotten a few reports of Delegate failures; spag numbers increasing after a spray. Remember, Sparganothis are particularly hard to manage as they are squirrely, web-up and resistant to all organophosphates. Intrepid added to Bravo for first fungicide will help for a few weeks and Altacor for first fruitworm should also impact any spag that are out there.

Bogside Workshop Friday June 21 8:30-10 AM at the Cranberry Station. Katie Ghantous and Hilary Sandler will demonstrate how to use hand-held flame cultivation devices to control weeds. We will be demonstrating a 'mini cannon'sprayer that can be mounted on an ATV, golf cart, or back of a pickup and sprays about 30 feet. Peter Jeranyama will cover irrigation issues, Carolyn DeMoranville will cover fertilizer use, and Frank Caruso will discuss disease management. This will be Frank's last event with us prior to his retirement at the end of the month!