Back to top

IPM Message for Cranberry Growers: May 1, 2017

May 1, 2017

It is time to get out and sweep!! Sweeps over the weekend indicate that winter moth, black-headed fireworm, and gypsy moth larvae are out.  They are very small!  You may need to wait and watch the sweep net to distinguish the small larvae from little pieces of leaf trash.  Marty found cranberry weevil over threshold on one sweep on Sunday, which was very cold and windy.  Sweeps on Saturday, which was near record warm temperatures, may have yielded even more. For more information, go to this UMass Fact Sheet on Gypsy Moths.

Applications of fungicides for Phytophthora should be out by May 15.  Both foliar and soil applications can be used.  Be sure to check the label of the product you are using as many of the foliar spray products have different REIs and application limits.

Treatments for control of upright dieback should also go out by May 15.  You can use Champ or chlorothalonil products.  Applications should be made once the bud has broken dormancy (begun to swell).  This is likely the case for all varieties at this point, except perhaps some cold locations with Howes.  If you use any chlorothalonil product for URD, you can only use 2 applications for fruit rot.

We have not yet had dodder emerge in the buckets that we monitor by the greenhouse on State Bog. You should be checking YOUR bog in warm areas and trash removal areas for seedlings.

We have had several reports, samples and bog visits on sites where the vines just look terrible and there’s a lot of leaf drop.  We are recommending applications of SulPoMag to help the vines along.  In many cases, the vines are definitely alive, they just do not have many leaves.  It’s possible that the stress from last summer’s drought combined with possible cold exposure over the winter may be contributing to the weak looking vines.