Week 8 - Insect Pests

For episode/article 8 for This Week in the Garden, we’ll cover insect pests in the garden. This is a topic that I could talk about for hours because there are so many small differences that make identification and treating insect pests difficult. Fortunately, this video is less than 5 minutes long, and I’ve tried to develop an easier method to I.D. insects in the garden.

The first step in identifying and getting rid of the insects that are feeding on your vegetables is to find the insects! Most insects hang out on the undersides of leaves or in notches of branches during the day. Plants that are bushy or plants/rows that are crowded are perfect places for insects to hide. I’ve found that vegetables like tomatoes, beans, and squash provide the perfect habitat for these pests. Proper pruning and spacing will drastically reduce your insect pressure.

Most insects aren’t a problem until they proliferate or aggregate in large numbers. Constant monitoring of your garden, whether that’s every day or every other day, will reduce your likelihood of outbreaks. If you find an insect while searching your garden, look to see if there are any feeding marks to determine if it might be a pest. If you’re not sure, let it be and check the same plant/area over the next few days to see if any injury has occurred, or if more have shown up. Once you’ve decided that it’s a pest, you’ll need to properly identify it to have a better idea of what treatment options are available to you.

In my mind, identification is the hardest part. I’ve taught a number of classes on this, but until you have a good understanding of insect physiology and taxonomy, it will remain difficult. But, who has the time or desire to do that? With that in mind, I’ve been trying to develop a way for people to I.D. pests with little knowledge of insects. I think I’m a little closer in what I call the “Google Method”.

The name may sound dumb, and it may seem obvious, but I’ve tested it a number of times and it works for most insect pests of the garden. The first step is to determine if the insect is a beetle or bug. Beetles have a hard outer wing called elytra, while bugs have a leathery wing that looks like a teardrop called hemelytra. The only other main pests group are caterpillars which most people can tell the difference of compared to beetles/bugs. The next step is to figure out what vegetable it is feeding on. Insect pests of vegetables generally feed on a select group of vegetables, which narrows down the search. The last step is to accurately describe the color or shape of the insect. Does it have spots, is it long, is it bright red or metallic? Combining the type of insect with the plant it feeds on and a description in an internet search is the easiest way to I.D. insect pests without much knowledge of insects. Of course, if you want to know more about insects, let me know by filling out our form and I can teach a painless online insect series!

Let’s test out this method. Here is an image of a common garden pest. You can tell it’s a beetle by the outer wings that are completely hard, no leather teardrop shape. Sometimes the insect’s abdomen will stick out, but that should be easy to differentiate from the wings as it’s segmented. Next, you need to know what plant it’s on, we’ll say a cucumber. The final step is a physical description. I’d say it is yellow with black spots. If you search “yellow and black spotted beetle on cucumber” in a search engine, you should see multiple pictures that look like this. Further investigation should help you I.D. this as the Spotted Cucumber Beetle. If you’d like to try for yourself, I’ve got a ten question quiz for practice.

That’s all for this article from This Week in the Garden. If you’ve missed any articles, check out our website where we keep them archived and fill out our form if you have any comments or questions. Of course, stay tuned until next time for This Week in the Garden.

-Adam