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IPM Message for Cranberry Growers: Jun 22, 2018

June 22, 2018

Do not spray for weevil or scale on most varieties at this time.  You might be able to spray Howes if they are not yet in bloom. Please let the Entomology lab know if you have a scale problem or if you think you have a problem. They can help you diagnose it and we want to know how much is out there.  Spag and blackheaded fireworm moth flights are in progress.  See last week’s message for spray timing information. First fruit rot fungicide sprays should be out by now on all varieties, except Howes, in most locations.  Some Rutgers varieties may be ready for their second spray.

First fruitworm sprays are just around the corner.  Some Ben Lear pieces already have fruit sizing up on them.  Now is the time to be planning your CFW management approach as 50% out-of-bloom won’t be that far away.  Be sure to get at least ONE count before 50% oob; two are better. Altacor is your best choice for early fruitworm sprays; it does not work well on larger larvae.  First CFW spray for all varieties except Howes is 0-7 days after 50% oob.  The Chart Book recommendation for Howes is 7-9 days after 50% oob, but some growers are opting to spray when there are swollen pollinated fruit out there (i.e.,  a bit earlier than 7-9 days).  Apply your second treatment 10 days after the first one. Don’t wait to use Altacor later in the season; it is ok to two back-to-back Altacor sprays; you can use Delegate sprays later against larvae of both cranberry fruitworm and sparganothis fruitworm.

Clethodim products (Select, Intensity) cannot be sprayed between hook and fruit set. Poast is another grass herbicide with a related, but different, active ingredient (sethoxydim).  There is no label restriction on applying Poast during hook to fruit set.  It is recommended that Poast be used with crop oil, and grass control is more effective when it is included.  The label states that using Poast with adjuvants at temperature above 90° F (or anytime the temperature exceeds 100° F regardless of the humidity) and relative humidity at or above 60% may result in injury.  Flower petal fusing has not been observed with Poast use.