Tomato hornworms are notorious garden pests that can cause significant damage to your tomato plants. These large, green caterpillars can strip a plant of its foliage and ruin your chances of a bountiful tomato harvest. Fortunately, with some vigilance and the right strategies, you can effectively manage and eliminate these pesky invaders. Here’s a guide to hunting tomato hornworms and an extra tip for keeping your tomato plants healthy.

Identifying Tomato Hornworms

Tomato hornworms are the larvae of the five-spotted hawk moth (Manduca quinquemaculata). They are bright green with white and black markings and can grow up to 4 inches long. A distinctive horn-like projection on their rear end gives them their name. Despite their size, they can be surprisingly hard to spot due to their excellent camouflage.

Signs of Infestation

Before you see the hornworms themselves, you might notice signs of their presence:

• Defoliation: Large sections of leaves missing or completely stripped from the plant.
• Frass: Dark green or black droppings on the leaves and ground beneath the plant.
• Chewed fruit: Damage to tomatoes, often with large, open wounds.

Hunting and Removing Hornworms

1. Inspect Your Plants Regularly

Check your tomato plants daily, especially the underside of leaves and near the stems, where hornworms tend to hide. Early detection is crucial to prevent severe damage.

2. Handpick the Hornworms

Once you spot a hornworm, remove it by hand. Wear gloves if you’re squeamish about handling them directly. Drop the hornworms into a bucket of soapy water to ensure they don’t return to your plants.

3. Use a Blacklight

Hornworms fluoresce under ultraviolet light. If you’re having trouble spotting them during the day, use a blacklight at dusk or after dark to make them glow, making them easier to find and remove.

Biological Controls

4. Encourage Natural Predators

Beneficial insects such as ladybugs, green lacewings, and predatory wasps feed on hornworms and their eggs. Planting flowers like dill, fennel, and marigolds can attract these natural predators to your garden.

5. Introduce Parasitic Wasps

Braconid wasps are tiny parasitic wasps that lay their eggs on hornworms. The wasp larvae feed on the hornworm, eventually killing it. If you find a hornworm with white cocoons on its back, leave it be – it’s already been parasitized and will soon die.

Organic and Chemical Controls

6. Use Bacillus Thuringiensis (Bt)

Bt is a naturally occurring soil bacterium that produces proteins toxic to caterpillars. Spraying your plants with Bt can effectively control hornworm populations without harming beneficial insects.

7. Apply Insecticidal Soap or Neem Oil

For severe infestations, insecticidal soap or neem oil can be effective. These treatments should be applied according to the manufacturer’s instructions and can help reduce hornworm numbers without resorting to harsh chemicals.

Extra Tip for Healthy Tomato Plants

Mulch Your Tomato Plants

Mulching your tomato plants can offer several benefits. It helps retain soil moisture, suppresses weed growth, and prevents soil-borne diseases by keeping soil from splashing onto the leaves. Use organic mulch, such as straw, grass clippings, or shredded leaves, and apply a 2-3 inch layer around your plants, being careful not to cover the stems directly.

Conclusion

By staying vigilant and employing a combination of manual, biological, and organic methods, you can keep tomato hornworms at bay and protect your tomato plants. Regular inspection, fostering beneficial insects, and using safe treatments will ensure a healthy, productive garden. Don’t forget to mulch your plants to provide additional protection and promote overall plant health. Happy gardening!