Friday, February 28, 2020

An Oldie But A Goodie

An Oldie But Goodie
By Kristina Hughes
Clear Creek County Master Gardener
Clinician, Diagnostic Plant Clinic, Jefferson County Extension

Have you ever found tiny holes in the leaves of your spinach plant and wondered what caused them? Or have you found little caterpillars demolishing your rose buds before they could become flowers? Or maybe one year your pea plant didn’t grow as vigorously as you’d expected.

There are so many maladies that can affect our garden and it can be hard to figure out exactly which of the many possibilities is the actual culprit in any given instance. A lot of damage looks similar and everyone, from your neighbor to the garden center, has advice about their own fool-proof remedy.

In the Diagnostic Plant Clinic at the Jefferson County Fairgrounds, we sort through the confusion and get to the bottom of all kinds of plant problems. We use lots of different books and websites to identify the most likely culprit.

Pests of the West by Dr. Whitney Cranshaw
A favorite resource of our most seasoned Clinicians is Pests of the West, revised edition c1998 by Dr. Whitney Cranshaw. It is a small book, but it covers an impressive array of topics in simple straightforward language. It focuses on common issues in our region and it is especially good for solving vegetable problems.

Using our first example above, you can dive right in and look up common disorders of spinach. ‘Holes in leaves’ are likely caused by flea beetles. Go to page 87 to find further details on Western Cabbage Flea Beetle (Phyllotreta pusilla). Typical damage of flea beetles is described, so you can double-check if it’s a good match for what you see on your plant. If it is a good match, read on for control methods.

Dr. Cranshaw includes many control options, from beneficial insects and cultural practices, which enhance the health of the plant, to chemical controls of varying intensity. If you want to better understand how the control methods work, Cranshaw includes detailed information about each control strategy to help you decide which is appropriate for your situation. The book takes the guess work out of trouble-shooting garden problems.

Most garden books are geared toward climates with more moisture than ours, and it can be hard to find advice appropriate for our climate. Pests of the West addresses issues specific to the arid west. In the introduction Cranshaw states “a discussion of soil problems unique to the West is...the place to start.” Chapter 1 tells us salts are common in arid areas and goes on to explain why. He says “potassium is rarely deficient” in our region. And clay soils hold water, which can be an advantage in our arid climate. I have found this to be true in my personal experience gardening in Colorado. He then goes on to discuss the pros and cons of clay soil.

There are chapters on a wide range of topics and in each Cranshaw highlights issues particular to our area. The chapter on butterfly gardening has a table listing plants used by the butterflies that live in our region. Birds eat insects, especially when raising their young. Pests of the West includes advice on attracting specific, western birds to nest in your garden.

There is a section on mammal garden pests, including an extensive discussion of deer, which are a huge issue for us the mountains. Cranshaw describes the damage done by deer as ‘ragged’ because deer lack upper incisors. This is different from the very clean cuts made by rabbits, which have both upper and lower front teeth.

There is so much more contained in this book, I could go on and on. I really appreciate how small the book is and its accessible style. I have used it as a reference book in the past but after reviewing it more closely for this article, I am even more impressed with its breadth and how well it hones in on issues specific to our region, which are often neglected in mainstream garden books.

It does not address lawns, which are rare in the mountains anyway, nor landscape plants. The focus is vegetables, fruits, iris and roses. The photos are black and white, but it is easy enough to find photos on the internet once you have narrowed down the possible problems. Even though the book is older, I find the information to be very relevant.

Pests of the West, revised edition is an excellent all-around reference for understanding the issues we face in our Colorado gardens and for solving garden problems common to our area. It was published by Fulcrum Publishing in Golden, CO in 1998. Used copies are readily available online.

PS - I lost all of my rosebuds one year to Tobacco Budworm (Heliothis virescens), page 103. And slow growing pea plants can be due to high temperatures, page 61.

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