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IPM Message for Cranberry Growers: July 21, 2022

July 21, 2022

We recommend scouting for Putnam scale now. Outbreaks and vine injury were apparent on many acres this spring and scale was successfully managed in early June. However, new scale spots have appeared on other bogs.  During bloom, many small areas that looked burned and had fewer flowers turned out to be scale spots.  Now, the affected vines appear off color, and scales can sometimes be found on the leaves and berries.  A vulnerable population of immatures (crawlers) emerge once again in August from under the protective cover of the female and can be managed with a well-timed spray.  We are monitoring a number of bogs, so keep in touch if you are planning a spray (Marty 508-265-6921).

Bees continue to be pulled from bog sites and if your bloom is complete, Actara could be used at this point if weevil numbers are very high (10-25+).   

If you have done your 2 Altacors for Cranberry Fruitworm and you have a history of Sparganothis, now is the time to apply your Intrepid (or Delegate).  

Of course, the topic of the day is the heat and drought.  Cranberries really do not fair well when temperature exceed 85F; they start to shut down and go into photorespiration. Here is some guidance on keeping your vines and fruit cooler.

When to run:

run sprinklers mid-day when there are temperatures greater than 85 F, if the dew point is less than 55 F during midday hours, wind speed more than 11 mph, and no rainfall in the past 48 hours.

How long to run:

If the heads on your sprinkler system complete their rotation quickly, that is advantageous as you get the evaporative cooling effect in a short time frame. The irrigation system can shut down sooner and minimize the increase in soil moisture. Run for 10 minutes.

With older systems and/or those with slow rotating heads, the opposite is true, and the balance is harder to maintain. Run for 20 minutes.

We will be hosting a Zoom Bogside meeting on Tuesday, August 9 from 9-10 am.  1 contact hour will be offered.  We will be covering scale scouting and timing for the August generation.  Heat stress and scald will also be covered. Please contact Robyn Hardy for link information.