July and August are when New Mexico gardens are reaching their peak production!
Tomatoes are ripening.
Squash is producing.
Flowers are in full bloom.
Unfortunately, it's also when many of our most common garden pests become active.
The good news? Most problems can be managed if you catch them early. Here are six pests we're seeing most often this time of year—and what you can do about them.
🐛 Tomato Hornworms
If you've ever walked out to a healthy tomato plant only to find half the foliage missing overnight, you've probably met a tomato hornworm.
These large green caterpillars blend in remarkably well with tomato leaves and can strip a plant surprisingly quickly.
Look for:
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Missing leaves
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Large chew marks
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Dark green droppings beneath the plant
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Large green caterpillars with a horn-like tail
The easiest control method is simply picking them off by hand and placing them somewhere a hungry bird is likely to find them!
Before You Squish One...
If you find a hornworm covered in tiny white, rice-like cocoons, leave it alone.
Those aren't hornworm eggs.
They're the cocoons of beneficial parasitic wasps that are naturally controlling the hornworm population.
The hornworm won't survive, and the next generation of wasps will help protect your tomatoes from future pests. Sometimes nature is already doing the work for you.
🪲 Squash Bugs
If your zucchini, pumpkins, cucumbers, or squash suddenly begin wilting despite adequate water, squash bugs may be the culprit. Few pests frustrate New Mexico gardeners more than squash bugs!
Both adults and immature nymphs feed by piercing leaves and stems, weakening the plant over time.
Look for:
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Bronze-colored egg clusters on the undersides of leaves
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Gray nymphs
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Brown, shield-shaped adults
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Wilting vines
Inspect plants regularly and remove egg clusters before they hatch.
Over the years, we've tried just about every recommended squash bug control method—planting later in the season, growing squash vertically, using diatomaceous earth, hand-picking insects, and more.
What we've consistently found to be the most successful is planting squash in a newly established garden bed. Squash bugs commonly overwinter in garden debris and nearby soil, so planting squash in the same location year after year often gives emerging adults an easy meal when spring arrives.
If you've just started a new garden with fresh soil, early July is not too late to plant squash. Consider fast-growing varieties such as zucchini, spaghetti squash, or acorn squash.
If you've struggled with squash bugs in the past, consider rotating your squash crop to a different area of your garden and waiting a few years before planting squash there again. While crop rotation isn't a guarantee, we've found it to be one of the most effective long-term strategies for reducing squash bug pressure in the home garden.
One more tip: At the end of the growing season, remove old squash vines and plant debris rather than leaving them in the garden. This helps eliminate many of the places adult squash bugs use to overwinter and can reduce next year's population.
🕷 Spider Mites
Our hot, dry New Mexico summers are ideal for spider mites.
They're tiny—almost impossible to see—but their damage is easy to recognize. Watch for:
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Tiny yellow or white speckles on the undersides of leaves
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Bronzed foliage
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Fine webbing on heavily infested plants
Spider mites thrive in hot, dry conditions, so a strong spray of water on the undersides of leaves every few days can often keep populations under control.
We've also had great success using organic controls. Horticultural oil or neem oil can suffocate spider mites and disrupt their life cycle, helping to keep populations in check.
(Spider Mite webbing on boxwood plant)
🪰 Aphids
Aphids are one of the most common garden pests and can appear almost overnight.
Fortunately, they're also one of the easiest to manage.
Signs include:
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Curled leaves
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Sticky honeydew
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Clusters of tiny green, black, yellow, or red insects
Before reaching for an insecticide, look closely.
Lady beetles, lacewing larvae, hoverflies, and other beneficial insects often take care of aphid populations naturally.
(Check out the ladybug at the top right of this photo. It's about to feast on all these aphids. Adult lady beetles eat about 50 aphids per day!)
🦗 Grasshoppers
Every New Mexican knows grasshoppers can be frustrating.
They're especially troublesome during dry years, when they move into landscapes looking for fresh green growth.
Young vegetable plants and flowers are particularly vulnerable.
Floating row covers and encouraging birds can help reduce damage, although large outbreaks can be challenging to control completely.
🐛 Budworms
If your petunias looked beautiful one day and the next morning the blooms suddenly have holes—or the buds never seem to open—you may have tobacco budworms.
These small caterpillars feed inside flower buds and blossoms before gardeners even notice they're there.
Petunias are one of their favorite targets, but they'll also feed on calibrachoa, geraniums, nicotiana, and other ornamentals.
Watch for:
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Flower buds that fail to open
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Ragged petals
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Tiny green or brown caterpillars hiding inside blooms
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Small black droppings on flowers
Removing damaged blooms and inspecting plants regularly can help keep populations under control before they spread. My first choice is always hand-picking. However, if caterpillars become a big problem, Bt (Bacillus thuringiensis) is one of my favorite organic tools. It’s a naturally occurring soil bacterium that specifically targets caterpillars. Once they feed on treated leaves or flowers, they stop eating and die within a few days. Because Bt is so selective, it has very little impact on beneficial insects, birds, pets, or people when used as directed.
Healthy Gardens Aren't Bug-Free
Every garden has insects.
That's perfectly normal.
The goal isn't to eliminate every bug you see.
It's to create a healthy, balanced ecosystem where beneficial insects help keep pest populations in check.
Healthy soil grows healthy plants.
Healthy plants are naturally more resilient to insects, diseases, and environmental stress.
So before you reach for a spray bottle, spend a few minutes observing what's happening.
You may discover that nature has already sent in the reinforcements.
Healthy soil grows healthy plants—and healthy gardens are full of life.
