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IPM Message for Cranberry Growers: Apr 17, 2020

April 17, 2020

Although the Station buildings are not open, we are “open for business” and accessible by phone or email ( ). Please call us.  It is great to hear from you.  Chart Book updates have been mailed out by both email and snail mail.  If you need a new 2018-20 Chart Book, contact Krystal at to arrange a pick up.  We are accepting samples for diagnoses. Please call Leela at 334-728-1025 to make arrangements.

The Preliminary Keeping Quality Forecast is FAIR; we got 3 out of 10 points.  Based on the preliminary forecast, fruit rot fungicide applications and the rate of fungicides applied should not be reduced. As for the holding of late water, there are no definitive indicators pro or con. LW floods for inland areas are out by now with Coastal Plymouth flooding between April 15-20 and the Cape at April 20 or later.

Late Water is Advised:

  • Once in three years for 4 weeks from Mid-April to Mid-May.
  • If your bog looks healthy and not showing signs of stress.
  • If your bed was properly flooded at the periods of coldest temperatures.
  • If the scale and/or fruit rot incidences were high in 2019.
  • If you have access to good quality water supplies.

Late Water is Not Advised:

  • If you held late water in the past three years.
  • If your bog produced a heavy crop in 2019.
  • If the bed was sanded the previous year.
  • If the bog is stressed and shows signs of winter injury.
  • If your bog is severely out of grade.


We will be holding a virtual (zoom) Grower Lunchtime Bogside on Wednesday May 6, 2020 12:00-1:00 PM.  More than 30 folks attended our first one. We will discuss more herbicide timing, fertilizer recommendations, early season insect management, winter moth, gypsy moth and blackheaded fireworm, and continued timing and chemical options for upright dieback as well as fairy ring.  Please contact Robyn Hardy at or 508-295-2212 x10 for the meeting information.

 We have a Special Local Needs label for the herbicide, Zeus, which can be used to control of moss. Applications should go out BEFORE the buds reach cabbagehead stage to minimize injury to the vines; for some varieties and locations, that window could be closing soon.  It is Zone II restricted, so if you want to apply in a Zone II, email me your bog’s address (and GPS coordinates, if you have them).  Zeus may control other weeds, such as dodder, and it is legal to use the herbicide to target weeds other than moss.  Please see our March 2020 newsletter for more information.  We would NOT recommend using Zeus on new plantings. Please only treat only a small bit of your acreage in 2020. We suspect it should be fine, but we want to start small and mitigate any possible issues before people start to use it on a large scale.  We applied Zeus to State Bog (~ 3.5 A) on Wednesday April 15.

We also have a Section 18 Emergency Exemption to use Kerb for dodder control.  The permit is active from April 15 through June 30, 2020.  Copies of the label are available on our web site at:

and from wherever you will buy your product.  You will need to report your use of Kerb to MDAR by November 30, 2020. Forms are available on our web site or where you buy your product. If you are in a Zone II and want to use Kerb, please follow the notes above for Zeus.