How to Use Lime to Kill Hornworms

Hornworms get their name from the horn appendage on the tail.

Hornworms, also known as tomato or tobacco hornworms, are the caterpillar of the hawk or sphinx moth. They are common pests of potato, tomato, eggplant and pepper plants in the garden. These worms can quickly consume the foliage of the plant. They are large and easy to spot, which makes hand removal the best method for control. You can also spray the affected plants with a lime mixture to kill any hornworms you miss.

Things You'll Need

• Spray bottle
• 32-oz. water
• 1-oz. hydrated lime
• 1 teaspoon castile soap

Instructions

1. Fill a spray bottle with 32 oz. of water. Pour in 1 oz. of hydrated lime and 1 tsp. of castille soap.

2. Put the lid on the bottle and shake until the ingredients incorporate. Spray the plants completely with the lime mixture.

3. Repeat the spraying twice a week. Avoid spraying hornworms that have white, rice-like growths on their backs. These are the larvae of parasitic wasps, and are beneficial in the garden.

References

• Colorado State University; Tomato/Tobacco Hormworms; Judy Sedbrook
• GH Organics: Lime Spray