Fungicide use

Asked May 21, 2019, 1:03 PM EDT

Hello: We just discovered yesterday that we've got rust forming on some of our new apples and powdery mildew on 2 apple trees as well. We were going to spray with Copper fungicide, but it looks pretty toxic. Would Sulfur be a less toxic choice and as effective? If we did end up using the copper, should we wear a respirator, goggles and clothing protection? Anything else we should be doing for the rust and mildew? Thanks very much!!

Multnomah County Oregon apples rust

1 Response

Hello and thanks for your question! Good job identifying both problems early. You may know this, but it's a good idea to remove and burn diseased branches and leaves. Sanitize your tools before using them again.

Both rust and powdery mildew spread when spores move with water/wind to uninfected parts of the plant. Spores are produced continuously for powdery mildew, and rusts generate spores after a rain event, typically.

This publication may be perfect to meet your needs.
https://catalog.extension.oregonstate.edu/ec631/html

Be sure to click on the table called "Apples" to see a list of recommended products and practices. There are some lighter options presented, compared to copper. Also included in the publication, good practices when handling pesticides. Lower exposure is lower risk. Whatever product you choose, follow the label directions. The label will tell you which personal protective equipment is required (i.e. gloves, respirator, etc.).

Thank you again!
Kaci