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IPM Message for Cranberry Growers: May 8, 2018

May 7, 2018

We have heard of several reports of single gypsy moth larvae; most were off-bog but one was on-bog.  We think it will be a low GM and winter moth year, but if you have had issues with these insects in the past, you should start sweeping and monitor your populations. We also had a report of 1 cranberry weevil on-bog.

If you are treating for upright dieback, you want to cover the newly emerged tissues, so you want a little bit of growth to be apparent. Sprays go out based on the condition of the vine and usually between April 25 and May 15. One pre-bloom application is recommended.  You can use Champ or Chlorothalonil products. If you use chlorothalonil for URD, that gives you one less spray of chlorothalonil for fruit rot control. Make sure the product you use has upright dieback on the label.

If you are planning to applying fungicides for Phytophthora control, now is the window. You can use Aliette and many phosphite products are available.  These are foliar-applied fungicides. Soil applications can be made with the Ridomil or other phenylamide products; check the Chart Book and the label!!  Ridomil Gold can only be applied by ground or air; no chemigation. Before starting ANY fungicide program for Phytophthora, get a diagnosis first; if positive, fix the drainage and THEN start a fungicide program.

If you haven’t already checked out the excellent bud development/frost pictures on our web site, please click on this link: http://ag.umass.edu/cranberry/frost-tolerance-reports