Cranberry IPM Message

IPM Message for Cranberry Growers: May 6, 2022

To hear audio recording, call 508-258-9191.

No good sweeping days except this past Thursday (end of next week looks good too!). Many growers got out and found generally clean bogs. Just a few weevil here and there; few flies and spiders. Just a few very small green spanworm here and there. No treatable populations anywhere reported. Picture has 3 tiny green spanworm circled.

Some bogs went under water due to the rain on Wednesday night into Thursday. This is a bad time to have fruit under water. Applying a fungicide at this time will not help reduce fruit rot but could give you peace of mind. Growers should do all they can to get the water off as soon as possible (including from low spots of the bog). That would be the most critical action to take at this time.

Flea beetle continue to be a nuisance feeding on overgrowth on the bog. Unless you sweep and get 25 or more on average per sweep set, it does not warrant using a Diazinon at this point.

Sparganothis fruitworm is starting to show up in berries, only about 1/4". If Altacor applications did not get on or if spots were missed, cranberry fruitworm red berries are clear now. Flea beetle are out now feeding on lush growth. Upright dieback has started to appear on some bogs.

Dealing with scald

If growers missed the timing on their Altacor, red berries are starting to show up. Chasing these with very expensive Delegate is likely a bad idea as it will only hit a few of the larvae in the berries. However, timing now with Delegate or Intrepid is rather good if you had high Sparganothis moth flight and want to hit those hatching eggs and young larvae.

Most growers are finishing up fruitworm and fungicide spraying. Altacor for fruitworm is a good choice and you should allow at least 7 days between applications, 10-14 is better. It does have a good residual but don’t take chances and possibly miss your application window. Do not exceed 9 oz/A per season.

Weevil is definitely an issue! We have heard reports of very high sweep counts. You must wait until bees are removed to spray Actara! Exirel is not a good option for weevil and certainly not at this time of year (cannot be used during bloom and is expensive).

Timely application of management strategies with consistent monitoring of bloom is very critical to achieve the best fruit quality. Bloom monitoring is also important if any of your handler chemical usage restrictions are associated with bloom progression. In the past two weeks, bloom is progressing at a quicker pace.

We had one report last week of what we believe is Funky Flower. The pathogen is unknown but thought to possibly be a soymovirus. The flowers are distorted, usually a vibrant pink color; it causes vegetative...

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