Advice to growers: Match the cure to the pest problem

This undated photo shows cedar apple rust infection on cedar in New Paltz, N.Y. Cedar apple rust begins its seasonal cycle on cedar trees and is one of many diseases attacking apples, but not all apple varieties are susceptible. (Lee Reich via AP)

This undated photo shows cedar apple rust infection on cedar in New Paltz, N.Y. Cedar apple rust begins its seasonal cycle on cedar trees and is one of many diseases attacking apples, but not all apple varieties are susceptible. (Lee Reich via AP)

The caller on the other end of the phone was worried: Her apple trees had suffered severely last year from cedar-apple rust disease, and she wanted to know how to keep them from being attacked again.

I can offer two important pieces of advice, whether you’re growing apple trees or any other plant.

1. Plants vary in pest resistance

When putting in new plants, consider pest-resistant varieties, if they exist. In the case of apples, Golden Delicious and its progeny generally are most susceptible to rust disease. Some apples, such as the tasty variety Liberty, are resistant to rust as well as other major apple diseases.

Your plants may be spared a particular pest problem because that pest never makes it to your garden. Cedar-apple rust, for example, is pretty much absent where susceptible juniper species — Eastern red cedar, Rocky Mountain juniper, creeping juniper and common juniper — are not native.

Powdery mildew, on the other hand, is among those pests that threaten the health and beauty of phlox plants almost everywhere from midsummer on. However, varieties such as Katherine and David are among those resistant to it.

If your hybrid tea roses are being decimated by blackspot disease, another frequent unwanted visitor to gardens, why not try the old-fashioned, soft pink Blush Moss or the English rose Tamora, whose cuplike blossoms are the color of peach ice cream? Neither of these roses is particularly affected by blackspot.

2. If spraying, choose an appropriate spray

My worried caller was not interested in replanting and waiting for new trees to bear fruit. She said she might try an oil spray to bring the needed relief. Which brings us to our second bit of advice on pests: Before you spray, make sure you’ve got the right one. In the case of cedar-apple rust, spraying oil would be a waste of time.

Too many gardeners rush to the garden store when a pest threatens and reach for anything with “-icide” on the container. But “insecticides” control only insects; “miticides” control only mites; “nematocides” control only nematodes; and “fungicides” control only fungus diseases. And a given insecticide does not necessarily control all insects; the same goes for the other “-icides.”

So spraying a fungicide on your rose, whose leaves are mottled white because of a virus disease, would be for nought. Spraying B.t., short for bacillus thurengiensis, can be an environmentally sound way to control caterpillars, but would have no effect on cedar-apple rust.

“Pesticide” is a very general term. For effective control, match the specific pesticide to the general kind of pest — or even better, the specific pest — that’s gotten out of hand.

Garden sprays are available that contain mixtures of insecticides and fungicides. Such sprays are easy to use, but they have a financial and environmental downside. They cost more and you’ll likely be dousing the environment with some pesticides that are not needed.

Always read the fine print on the label, whether it’s a mix of pesticides or a single pesticide, to find out just what pests will be controlled. Not only does this ensure that your spray is effective, but it keeps you on the right side of the law. It is illegal to spray for anything except what is listed on the label, or in a manner other than specified.

Also consider other measures to thwart pests, such as giving a plant a good site and growing conditions, cleaning up or pruning off diseased parts and, in the case of annuals, timing plantings to avoid certain pests.

More in Life

Make-ahead stuffing helps take pressure off Thanksgiving cooking. (Photo by Tressa Dale/Peninsula Clarion)
Holiday magic, pre-planned

Make-ahead stuffing helps take pressure off Thanksgiving cooking

tease
Off the shelf: Speculative novel holds promise of respite

“A Psalm for the Wild-Built” is part of the Homer Public Library’s 2024 Lit Lineup

The cast of Seward High School Theatre Collective’s “Clue” rehearse at Seward High School in Seward, Alaska, on Thursday, Nov. 7, 2024. (Jake Dye/Peninsula Clarion)
Seward’s ‘Clue’ brings comedy, commentary to stage

The show premiered last weekend, but will play three more times, on Friday, Saturday and Sunday, Nov. 15-17

The cast of “Annie” rehearse at Kenai Central High School in Kenai, Alaska, on Wednesday, Nov. 6, 2024. (Jake Dye/Peninsula Clarion)
Kenai Central hits the big stage with ‘Annie’

The production features actors from Kenai Central and Kenai Middle School

Andrew Garfield and Florence Pugh in “We Live in Time.” (Promotional photo courtesy A24)
On the Screen: Pugh, Garfield bring life to love story

“We Live in Time” explores legacy, connection and grief through the pair’s relationship

Mary Nissen speaks at the first Kenai Peninsula history conference held at Kenai Central High School on Nov. 7-8, 1974, in Kenai, Alaska. Photo provided by Shana Loshbaugh
Remembering the Kenai Peninsula’s 1st history conference — Part 2

The 1974 event inspired the second Kenai Peninsula history conference, held in April, 2017

This slow-simmered ox tail broth makes this otherwise simple borscht recipe quite luxurious. (Photo by Tressa Dale/Peninsula Clarion)
Borscht from the source

This homestyle stew recipe draws on experience of Russian cook

In 1954, David Nutter (right) and his younger half-brother Frank Gwartney were ready for their first day of school in Sitka. (Photo courtesy of the Nutter Family Collection)
Finding Mister Nutter — Part 6

Chasing down the facts about Warren Nutter was never going to be simple

Photo provided by Shana Loshbaugh
Dena’ina writer, translator and ethnographer Peter Kalifornsky speaks at the first Kenai Peninsula history conference held at Kenai Central High School on Nov. 7-8, 1974.
Remembering the Kenai Peninsula’s 1st history conference — Part 1

Kenai Peninsula history gathering 50 years ago remains relevant and rousing

Most Read