Select Page

Gardening on the Oregon Coast, and the entire Pacific Northwest for that matter, has unique issues. Let’s face it, we’re special. If it’s not one challenge, it’s another. Whether it’s temperature, pests, soil or disease, every year we are usually battling a number of issues.

There are a lot of books and webpages that have the information we need, but it’s not always easy to find. And truthfully, it’s pretty overwhelming because half the time I’m not even sure what to search for in the first place.

For example, I have an apple tree and the apples are small and have brown spots. Because I’ve never had apple trees before (remember, I’m from New Mexico – unlike Oregon, every house didn’t have an apple tree) I asked a neighbor if they knew what was wrong with our tree. She said it was apple scab and I needed to spray it.

With what?


That brief conversation provided two answers, but still left me with questions. Primarily, what is scab?

Recently, I took a gardening class on plant disease and it was there that I was turned on to an amazing science-based resource for problems related to insects, disease or weeds.  And best of all, it’s FREE!

The Pacific Northwest Pest Management Handbooks, is a collaboration between Oregon State University, Washington State University and the University of Idaho. The site contains three handbooks: 

Insect Management Handbook

Plant Disease Management Handbook

Weed Management Handbook

And my favorite part is that they are searchable! The handbooks are available for purchase and are updated every year. However, they are also available online, for FREE. And the online version is always the most up to date version. I choose the free, online edition as my go to reference.

So, back to the problem. Apple scab and copper spray. Now what? Below is a walk-through of what I found on Pacific Northwest Pest Management Handbooks.

The homepage is simple and straight to the point. Is the problem related to insects, weeds or disease? Scab is a disease, so I typed “scab” into the disease search window. One of my favorite features of their search window is that it brings up all the results for topics with the term “scab” before I even hit the apply button. Here, we can see Apple scab is the first option.

Here I added in the search term “scab”.




I clicked on Apple scab, then clicked apply. This brings up all the apple scab options. I clicked the apple scab, not crabapple scab, option.


Here, I was in geek heaven. The first thing I did was look at the pictures to make sure my scabby apples matched the official “apple scab” images. It was a match. But what is scab? The first section included lots of information on the cause and what it is – spoiler alert: it’s a fungus.


Scrolling down, we can see symptoms of apple scab. Confirmed again, my trees have apple scab.


The next section is my favorite – cultural control. These are that we can do to control, prevent or make less likely for apple scab to continue to be a problem. If you’re interested in Integrated Pest Management, then you know cultural control is our first approach to keeping our gardens healthy.


The next section covers chemical controls. I looked for copper spray, as recommended by a neighbor and what do you know – it isn’t a recommended chemical control for apple scab. While copper may work, I would choose to follow the recommendations of the OSU Extension Service.


As you can see, there are a lot of chemical options. The options include the chemical name and/or dilution, timing, and frequency. But which one should we choose? In the gardening class I attended, they recommended home gardeners only use the option with the “H”. The “H” is for home gardens, the “O” is for orchard farmers and the remaining – those are for the professionals. See image below.


So, based on the chemical recommendation in the PNW Handbook, I would use Bonide Captan 50 WP. The directions for dilutions and application are on the label. If a label is too small to see, you can often find it available online in a font that is actually readable.

It’s important to add here that when anyone uses a chemical, federal law requires that we follow the label. Using a chemical in alternative ways is illegal.

Lastly, the page ends with forecasting, if you really want to get your geek on, and references.


The Pacific Northwest Pest Management Handbooks is priceless as far as gardening resources go. It is free, science-based, provides plenty of information to appease our inner gardening geek, and is readily available. I get a lot of use out of it and hope you find it as a valuable tool to help with your gardening weed, insect and disease problems too.

What is your favorite resource for dealing with gardening problems on the Oregon Coast? Please share it in the comments. The more resources we have, the better!

Clean fingernails are a sign that your garden that needs attention.

Don't Miss Out On The Latest Dirt

Don't Miss Out On The Latest Dirt

Like what you've read so far? Join us now to receive the latest updates from An Oregon Coast Garden.

You have successfully signed up for updates. Your first email should be in your inbox right now!