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IPM Message for Cranberry Growers: Aug 9, 2013

August 9, 2013

News on the disease and insect fronts has been quiet. We have seen some flea beetle damage but reports are fewer. Remember that our fungicides work as protectants, not as curatives. That means if you apply a fungicide AFTER you see the rot, it will do no good. In general, applying fungicides this late is of little use. Consider managing your irrigation to allow the vines to be dry as much as possible; this helps to limit fungal growth. It is getting to be the time to put out bud set fertilizer applications if that is part of your nutrition program. This is usually 20-25% of your total N goes out in this dose.

If you plan to do tissue tests, collect your samples from mid-August through mid-September. You can get your samples analyzed locally or send them off to UMass for analysis. Samples should contain no more than the top 2 inches of growth (no roots, soil, runners, or fruit). Collect tissue from vegetative and flowering uprights. You typically need about 1 cup of vine tissue. Do not collect samples when the vines are wet and do not send the samples in plastic ziploc bags. Always request nitrogen determinations when you submit your samples. 

If you are still applying pesticides (e.g., 2nd application of Ridomil or Aliette for Phytophthora), be sure to observe all needed PHIs. Ridomil products have a 45-day PHI; Aliette has a 3-day PHI. The IPM Message will now only be updated on an "as needed" basis.