When is the best time to spray a cherry tree for worms?



The timing of your spray depends on the development of the fruit. We usually recommend starting applications at 1060 degree days after March 1 (base 41). However, the flies cannot penetrate the skin of the cherry to lay eggs until the cherry has developed a salmon-blush color. So use that guideline for when to start spraying. Check the fruits at the top of the tree and in the sunniest locations as these will color up first.

This excerpt came from last year (20080 advisory, go to  http://utahpests.usu.edu/ipm/files/uploads/AdvisoryUpdates/Advisory08/Fruit-IPM-05-28-08.pdf to see photo of cherry fruit appearance for timing of spray.

The best thing to do is to check the USU Fruit Tree IPM(Integrated Pest Management) Advisories that are emailed weekly to subscribers, or you can check online.

To check advisories go to http://utahpests.usu.edu/ipm/htm/advisories/treefruit

To subscribe go to http://utahpests.usu.edu/ipm/htm/subscriptions 

As of May 13th weekly advisory Degree Day accumulations, in Holladay is 600 and in West Valley is 644.  Look at our advisory for total of 1060 or go by physical appearance of salmon blush of cherry fruit to spray.

Posted on 26 May 2009

Maggie Shao
Horticulture Agent, Salt Lake County

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