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IPM Message for Cranberry Growers: Jun 30, 2011

June 30, 2011

The Ent lab reports several calls with growers reporting BHF larvae out on the bog. The larvae are about 0.25” long and counts have been as high as 5 or 6.  Do not wait to spray if you have numbers this high.  Usually the timing is 2 weeks after the ONSET of flight if using growth regulators like Confirm or Intrepid (and again 10 days later).  For other insecticides, including Delegate and Avaunt, apply 10 days after peak flight, which is usually during bloom.

Early cultivars such as BL have reached 50% oob already.  See page 15 of the Chart Book on calculating %oob.  Timing of this spray is critical.  If pressure has been high in previous years and berries are sizing up, spray should occur very soon after 50% oob.  Delegate, sprayed only at night when residues can dry by morning, is the compound of choice during bloom.  Keep in mind that all insecticides, with the exception of Confirm and Intrepid, are toxic to bees.  The timing is 0-7 days after 50% oob for ST and BL and 7-9 days for Howes and EB.  Your second treatment (if you are planning on this) goes out 10 days later.  Then fruit inspection starts.

I have had a couple of growers mention that they have had good success with controlling poison ivy using a combination sprays of 1.5 oz of Callisto and 1.5 oz of Poast plus an adjuvant (in a gallon of water).  The sprays were applied as spot treatments (Poast cannot be chemigated).  Most applications were put on late May or so.  Control was not total after 1 year of treatment, but growers who have tried this say that the combination significantly reduced the PI patch, especially if applied for at least 2 consecutive years.