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IPM Message for Cranberry Growers: May 6, 2013

May 6, 2013

Winter moth larvae were picked up in sweeps last week. There is only a small window of opportunity to get out and sweep this week before the poor weather conditions come in, so try to get out there to see if winter moth is on your bog. Growers were picking up averages of 8-10 larvae last week. They are very small but you should be able to see them. At this size, it is hard to tell if they are WM, black-headed fireworm or Spag, but most likely, they are WM. Avaunt is a good choice along with Delegate and Intrepid. 

Cranberry weevils have been swept in the past few days, but not in numbers to trigger a spray. Grey weevils have also been picked up, but these weevils do not eat cranberry.

Dodder seedlings have been reported inland over the weekend (May 4). Scout in the duff layer for emerging seedlings; you do not need to dig into the soil to find the seedlings. Plan herbicide treatments for about 2 weeks after early seedling emergence. Day-old seedlings were noted in Onset on May 8. Photo below shows single dodder seedling (probably several days old) on duff layer.

doddler seedling

The first frost warning was issued on April 16. Most growers have been out frost protecting almost every night since then as we have had 16 warnings. Protecting started earlier in the night for typical spring time protection such that we already have as many "pump hours" as we did all of last year.

We are past the window for applying preemergence herbicides in all but the coldest of locations. It is probably too early to be applying Callisto or other postemergence herbicides but if you are in a warm location and the weeds are up, you could be in the window. Callisto needs about 4 hours to become rainfast. Most growers should probably wait until next week before applying any early Callisto sprays. 

We are looking for sites to study POISON IVY. If you would be willing to help us out, please call extension 21 or 27. We will be testing combinations of Poast and Callisto (so no crop-destruct). We are also looking for DODDER sites where we can use QUINSTAR. We are getting desperate, so if you are cleared for using QuinStar and have dodder and would be willing to help us out, please call extension 21 or 27.