Q&A: What ate my tomato plants?
Meet the Tomato Hornworm: Your Garden's Best-Disguised Villain
Tomato Hornworms (and their close relative Tobacco Hornworm, pictured above) are one of the most menacing stealth destroyers of the garden world. With their green, almost alien-like appearance, they blend seamlessly into your tomato plants, munching away under the cover of foliage. These critters can grow up to 4 inches long and have a distinctive horn-like projection on their rear—hence the name. But by the time you actually see one, the damage they’ve inflicted on your tomato plants will likely be pretty severe.
Is anyone else feeling the Star Wars vibes off these guys? Are you ready for Jedi training? Let’s go.
The Clues: How to Identify Hornworm Damage
Before you can nab these stealthy caterpillars, you need to know what to look for. Here are the telltale signs:
Defoliated Plants: If your once lush tomato plants suddenly look like naked, hornworms might be to blame. They have a voracious appetite and can strip leaves virtually overnight. Damage usually starts at the top of the plant.
Chewed Fruit and Stems: These hungry caterpillars don’t stop at leaves. Look for large, open wounds on your tomato fruits and gnawed stems.
Frass (Caterpillar Poop): Look for dark green or black droppings around the base of your plants. It's a sure sign that hornworms are having a feast.
Note: they may also attack other plants in the nightshade family, like eggplants, peppers, and tomatillos.
Night Vision: Using a Blacklight to Spot Hornworms
Here’s where it gets fun (and now we’re in an episode of CSI: Garden). Hornworms have a secret weakness—they glow under blacklight. Grab a blacklight flashlight and head out to your garden after dark. Shine the light on your tomato plants, and watch these sneaky critters glow like neon signs.
The Battle Plan: Treating Hornworm Infestations
Once you’ve identified the culprits, it’s time to take action. Here’s your battle plan:
Handpicking: It might sound gross, but handpicking is probably the most effective method of control. Arm yourself with gloves and pluck those pests off your plants. Drop them into a jar of soapy water to ensure they don’t come back.
Beneficial Insects: Use the Force (of nature)! Introduce beneficial insects like ladybugs and lacewings to your garden. They love feasting on hornworm eggs and larvae. They will even lay their own eggs on the hornworm so the babies can eat as soon as they hatch!
Bt (Bacillus thuringiensis): For a more hands-off approach, spray your plants with Bt, a natural bacterial insecticide that targets caterpillars. It’s safe for plants, pets, and humans but deadly for hornworms. Usually this is best for small insects. If they are already 3+ inches, definitely pick them off.
Prevention: Keep Hornworms from Invading
To keep hornworms from returning, try these preventative measures:
Companion Planting: Plant alyssum, marigolds, and dill near your tomatoes. These plants can help repel hornworms and invite the beneficial insects that attact them.
Regular Inspections: Make it a habit to inspect your plants regularly. The sooner you catch an infestation, the easier it is to manage.
Victory in the Garden
With these tips and a trusty blacklight(saber) in hand, you’re ready to defend your tomatoes from the tomato hornworm. Remember, a keen eye and a proactive approach are your best weapons. Happy gardening, and may your tomatoes grow plump and hornworm-free!
Feel free to share your own hornworm stories or tips in the comments below.
