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IPM Message for Cranberry Growers: May 28, 2010

May 28, 2010

Black-headed fireworm moths have been caught in traps.  We saw our first one on Monday of this week.  When treating the summer generation with Intrepid or Confirm, timing is 2 weeks from the onset of flight, so you must be monitoring now!!  The second spray would follow 10 days later.  If using conventional insecticides, apply 10 days after peak moth flight, which is usually during bloom.  Avaunt and Diazinon are also best management choices.  Cranberry fruitworm moths have also been reported and Spag is out as well.  Be sure to check your traps at least weekly and change the lures and bottoms as needed.

It is likely that early varieties in warm locations will need their first fruit rot fungicide spray early this coming week.  Fungicides should be made based on the Keeping Quality Forecast.  The Preliminary KQF was GOOD (5 out of 10 points).  We may get one or two more points.  In some cases, the number and/or amount of fungicide could be reduced this year, so consider your fruit rot history in this decision process.  Use of Abound and Indar are best when made pre-infection, so include these fungicides earlier in your schedule if you will be using them.  Be careful with your use of these products as resistance development is very real.  Do not use these products more than twice per season.  Chlorothalonil products are Zone 2 restricted; hold water for 3 days.  Water must be held for 14 days after an Abound application.

Some growers have called asking about a quick formula for Callisto mixes.  If you add 1 oz of Callisto to 6 gal of water, that is equivalent to 5 oz/A (in 30 GPA) rate.  If you combine 2 oz of Callisto to 10 gal of water, that is equivalent to 6 oz/A (in 30 GPA) rate.  If you combine 2.5 oz of Callisto to 10 gal of water, that is equivalent to 7.5 oz/A (in 30 GPA) rate.  You would then need 3.2 oz of NIS for every 10 gal (and 1.9 oz NIS for every 6 gallons).  If using COC, use 12.8 oz for every 10 gallons or 7.7 oz for every 6 gallons.

Callisto (oz) 1 2 2.5
NIS (oz)  1.9 3.2 3.2
COC (oz)  


12.8 12.8
oz/A rate in 30 GPA    5 6 7.5

Keep in mind, that in general, you will get better performance from any herbicide when you apply it to plants that are not stressed.  So, it is good policy NOT to apply during hot, dry conditions when plants will be losing a lot of water or experiencing other types of stress.