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IPM Message for Cranberry Growers: August 5, 2022

August 5, 2022

Leaf Nutrient Analysis. If you want to plan fertilizer decisions based on leaf tissue tests, it is time to start thinking about scheduling collection of tissue samples, The best time to take samples is between August 15 and September 15. Samples should be collected particularly if a deficiency is suspected. For routine analysis, usually one sample per bog is adequate. If your acreage is more than 10 acres or is of varied productivity or differing varieties, taking more than one sample may provide more specific information.

Collect 1 to 1.5 cups of new growth, (leaves and stems), no more than 2 inches down from the tip. Sample randomly; mix vegetative and flowering uprights. If vines are dusty from any recently applied materials, rinse in clear water and allow to dry overnight on a paper towel. Wrap the sample and ship immediately for analysis. Do not use plastic bags as they promote mold. Be sure to request nitrogen determination.

Due to staffing shortages, UMass is currently NOT doing tissue tests, so you must send your samples to another lab such as UMaine ( or UConn (  You can also seek out commercial labs.

Red berries from Sparganothis and Cranberry Fruitworm are clearly apparent on bogs now.  It is, however, too late to manage these insects.  It is highly unlikely that Intrepid or Delegate targeting these insects will have much impact at this point.

Cranberry weevil numbers have gone down on most bogs.  They have moved into the woods to overwinter and again, sprays targeting them are ill-advised.

Flea Beetle has been reported on just a few sites and Diazinon sprays are only warranted if you have very high counts across the bog (25+).

Scale window is fast approaching.  We have scouted many bogs with summer scale damage and females are starting to size up.  Likely timing Aug 15 may be appropriate for a Diazinon management if the crawlers start to emerge.  Check with Marty if you are planning a spray.

Remember, most handlers require a pesticide report by Aug 31 so start getting that info together!

We are hosting a zoom bogside on Tuesday August 9, from 9-10 am. 1 contact hour will be offered. Please contact Robyn Hardy for the link.

This will be the last WEEKLY update. Please check the website for notifications of new messages. I anticipate updating 1-2 more times before we break for harvest and the winter.

Thank you for reading the IPM message.