Will Neem Oil Kill Tomato Hornworms?

Neem oil should be effective against all 1,450 species of hornworm.

Although adults don’t always deposit their eggs on domesticated plants, they occasionally do.

Although we’ll concentrate on two particular species, the neem treatments should work for any other species that harm your garden.

Tomato Hornworm (Manduca quinquemaculata)

Adults will deposit their eggs on tomato plants and other plants of the nightshade (Solanaceae) family, as the common name implies.

The adults are drawn to huge, fragrant white flowers on plants, where they consume the nectar and lay their eggs on neighboring crops.

The green caterpillars that hatch from the eggs will eat the plant before moving farther outside to areas that receive partial shade throughout the day. The eggs are frequently laid on new growth close to the plant’s stem.

Tomato hornworms are green in color with 8 white V-shaped lines running along their abdomen and a horn facing backwards on their last segment.

Tobacco Hornworm (Manduca sexta)

The Carolina sphinx moth is another name for the tobacco hawk moth, which is similar to the five-spotted hawk moth.

They consume plants in the nightshade family, much like their siblings, except this species prefers tobacco when it is available.

Contrary to tomato hornworms, tobacco hornworm caterpillars have red backs with a red horn and straight white lines.

This species, often known as goliath worms, is occasionally kept as a pet by children in the South.

Can tomato hornworms be gotten rid of with neem oil?

In the vegetable garden, neem oil serves as both a fungicide and a pesticide. It works on arthropod pests including tomato hornworms, maize earworms, aphids, and whiteflies that frequently consume your produce.

Neem oil also manages common fungus that develop on vegetable plants, such as:

  • Mildews
  • Rusts
  • leaf stains
  • Wilts
  • Rotten stem

Neem oil should be sprayed on vegetable plants twice—once at night and once in the morning. By spraying during these times, you can be sure that you are not harming any helpful insects, like bees, who are important for pollinating vegetable plants.

What are tomato hornworms sprayed with?

The natural insecticide Bt (Bacillus thuringiensis), a bacterium that acts as a stomach poison on some insect larvae but is harmless to other plants and animals, can be used. To be successful, Bt must be consumed by the caterpillars, and it must be reapply to plant foliage after rain.

Which plants should not be exposed to neem oil?

I started using neem oil in my garden a few years ago to get rid of spider mites and aphids, and I’ve grown to adore it. I’ve had great success using neem oil, which naturally repels insects, especially when it comes to keeping the pests away from my tomato plants.

But I recently discovered a hard lesson: Neem oil simply isn’t a favorite among all plants. Thus, the issue arises: Which plants should you avoid using neem oil on?

Herbs like basil, caraway, cilantro, dill, marjoram, oregano, parsley, or thyme shouldn’t be sprayed with neem oil. Neem oil should only be sprayed sparingly on plants with fragile or wispy leaves, such as spinach, arugula, lettuce, and peas, to avoid burning the foliage.

Be careful while mixing and applying neem oil, though, as even hardier plants with tougher foliage might be scorched (or even killed) if you don’t.

Neem oil is made to cover a plant’s leaves and any invasive insects lurking among them in an oily film that will suffocate some insects and harm many others by damaging their cells. Neem oil is an oil, though, so even on a moderate day, if you ignore good advise and spray at the wrong times, you risk literally cooking the leaves of your plants.

In light of this, let’s look at a list of plants that tolerate neem oil, those that are sensitive to neem oil, and those that don’t actually require neem oil because they already ward off many of the most pesky bugs.