Fitting in a spraying #544555 - Ask Extension


Fitting in a spraying #544555

Asked February 21, 2019, 12:07 PM EST

I know to spray when it's not freezing, and have heard that you want it to stay above 40 degrees for a 24 hr. cycle after. I also know you should spray when it's not likely to be wet for the next 24 hours. Those options have been limited in the past 2 months and I'm losing ground for spraying. I have some anthracnose in my apples and have so far been successful keeping it at bay with copper dormant spray. How important are these guidelines re moisture and temperature? Can I spray on a foggy day such as today, even though it's likely to freeze tonight?

Lane County Oregon

Expert Response

It is BEST to spray without rain and temps above 40 degrees.

Since we are not having many GOOD days, you can actually spray in the rain.......or get the spray on when every you can.  If the spray hits the anthracnose disease, it will kill the disease.  It is better to do this in dry weather so the spray stays around, but the key is TO SPRAY.
Ross Penhallegon Replied February 22, 2019, 12:25 AM EST

Of course, the label is the law, so always follow directions on the label. Many products are not labeled for application in wet conditions and applying them when it is wet could wash them off, harming non-target species and wasting time and money.

Most labels should describe how long before or after precipitation and in what temperatures the product can be applied. If you need help interpreting a label a great resource is National Pesticide Information Center:

Elizabeth Records Replied February 22, 2019, 6:08 PM EST

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