Hidden Springs Homestead may earn a commission for purchases made after clicking links on this page. Learn More.
Nothing is more frustrating than picking a tomato off the vine only to find that it is rotting from the inside out and has this pencil eraser size hole in it! The culprit that causes this kind of tomato fruit problem is the tomato fruitworm. Also known as the armyworm. Learn how to kill tomato fruitworms easily!
How do you kill tomato fruitworms organically and how do you control them so they don’t destroy your tomato crop?
3 pests that Can Destroy Tomatoes
Also known as the corn earworm or armyworm, it’s a caterpillar that eats on both the leaves and the tomato fruit. The holes can be shallow on the surface even deep into the center.
Not only does it leave a nasty holes in your tomato, it will immediately begin to rot from the inside out. Knowing the signs for them is part of the process of getting rid of them or killing them all together.
What are tomato fruitworms?
Tomato fruitworms are horrible! They are sneaky, hide really well and appear, it seems, out of nowhere.
If left undetected for only a few days, they can wreak havoc on your whole tomato crop. Have you noticed a tomato beginning to ripen on the vine only the next day to find this same tomato has already began to rot? If so you’ve got a pesky tomato fruitworm lurking around on your plant.
How to identify tomato fruitworms
So what does this armyworm look like? The young or small caterpillar has very distinct rows of dark bumps on its back and the older ones will have a dark gray or yellow to light brown stripes that run lengthwise on its whole body.
They can be even yellow, green and even reddish-brown in color and grow to about 1.5 – 2 inches long in size.
Many people refer to them as “black worms on tomatoes.”
Lifecycle of Tomato Fruitworms
Tan – gray colored moth with a single black spot in the center of each wing. Some say this look like eyes on it’s wings. The wing span is around 1.5 inches total.
They are nocturnal meaning they lay their eggs right at dusk.
The eggs of an adult moth are off white with a slightly flat-look, round shaped just about the size of pin head, so very tiny and hard to see.
They are easier to spot right before they hatch when they develop a reddish-brown stripe on them which makes them more noticeable.
The larva (worm) hatches into this tiny small light colored, with a brown or dark-colored head covered in hairs. The larva is what destroys your plants.
They feed off not only on the fruit, but also the stem as well as the leaves. It feeds on plants first and then moves to your tomatoes once they begin to ripen.
This is why many tomatoes that are not totally ripe, but pink in color are attacked. They prefer the fruit when it is going from green to barely ripe. Of course they do destroy green tomatoes too.
Can you eat tomatoes with holes in them? Once it eats its way into your tomato, it is no longer good. It should be thrown away. You should not eat tomatoes with holes in them!
When they are finished feeding, they drop to the ground near the plant and form a cocoon to start the cycle over again in about 14 days. One season can have multiple generations.
The pupa is brown cocoon that overwinters in the soil about 2-3 inches deep for protection. And in the spring it emerges to begin the cycle again.
Damage Done to plants by Tomato Fruitworms
The most noticeable damage is small holes in ripening fruit. We don’t seem to notice as much when they are feeding on the plant itself.
You can often cut the tomato open and find distinct tunneling through the tomato, with clear juice, frass and rot of the tomato itself.
How to kill tomato fruitworms organically
1) Attract Natural predators
Fortunately, tomato fruitworms do have natural predators. Attracting these to your your garden can be a huge help in controlling these pesky things.
- parasitic Trichogramma wasp
- big-eyed bugs
- minute pirate bugs
- damsel bugs
2) How to Prevent tomato fruitworms
- Minimize their food source. Avoid planting near corn or cotton – the corn plant is there favorite. So keep tomatoes as far away as possible.
- Watch for eggs on both sides of the leaves – begin by looking closest to the bloom. Pick off any leaves found with eggs and destroy them.
- You can use cover cloths to keep adult moth from laying eggs on your plants
3) How to Get rid of tomato fruitworms
- 1) Watch for larva which looks like a tiny worm
- 2) Apply Bt- Bacillus thuringiensis – liquid- this does break down in UV light – so you will need to apply it every few days at the first sign of eggs
- 3) Use Neem Oil or Insecticidal soap (see recipe below) once a week and after each rain
- 4) Apply Diatomacous Earth around the base of the stems to kill larva
- 5) Hand-picking when you can find them
To attract these natural predators to your garden plant – grow lots dill, parsley, asters, goldenrod, daisies, alfalfa and stinging nettles near the garden or very close to your tomatoes.
You Don’t have to let Tomato fruitworm win
I know it can be very frustrating to feel like your tomato crop is being destroyed by all these tiny holes in your tomatoes.
Don’t give up! Start the season early looking for eggs and those “moths” that flit around at dusk. If you can destroy the eggs before they hatch, you are way ahead in controlling tomato fruitworms.
Plant lots of the flowers to attract their natural predators and you’ll be enjoying harvesting delicious tomatoes every season.
So there you have it! Controlling and killing tomato fruitworms is possible with just a little knowledge and preparation. What is the first thing you’ll do to better prepare to control them and kill in your garden?
- 5 TBSP Castile Soap
- 1 Gallon Water
- Garden Sprayer
- Fill sprayer with 1 gallon of water
- Add Dr. Bronner's Castile Soap
- Shake to mix well
- Spray directly on stems, leaves (top and bottom) and fruit
Spray every 5-7 days and after each rain.
As an Amazon Associate and member of other affiliate programs, I earn from qualifying purchases.
More Gardening tips
- How to Grow Tomatoes
- 11 Common Mistakes Made Growing Tomatoes
- Growing Potatoes, All You Need to Know
- How to Grow Cabbage in the Home Garden
Dianne Hadorn is the owner of Hidden Springs Homestead nestled in the hills of East Tennessee. She is a Master Gardener and enjoys helping others learn how to grow and preserve their own food and sharing tips for living a more self-sufficient lifestyle.