Tiny 1/4 inch red worms are eating my ripe tomatoes

by Joseph Marincel
(Osakis, Minnesota)

Q. I have found tiny red worms by my tomato plants and have found small holes in ripe tomatoes. What might they be?

Tomato Dirt responds ...
A. Sounds like tomato fruit worms.

Tomato fruit worms can be cream, yellow, green, red, or brown. They feed on leaves, stems, and fruit. Worms (larvae) enter fruit, usually at the stem end, and can work their way through the entire tomato. The entry hole can be up to the size of a pea.

They attack a tomato by tunneling. The worm consumes the tomato’s interior and leaves a cavity filled with fluid and droppings. The tomato quickly decays and rots. Once tomatoes have been attacked by fruitworms, the fruit is no longer usable. Pick and discard them.

How to treat tomato fruit worms
Prevention is the most effective way to control worms (see below). Once larvae enter fruit, they cannot be treated directly, since they’re protected by the tomato’s exterior. But before that happens, you can take these precautions.

• Apply Bt: Bacillus thuringiensis (Bt)- sold commercially as
  Bonide Bt Pint - is a microbial biological control, considered to be very effective on fruitworms. Bt doesn't harm a majority of beneficial insects. It’s available in liquid, powder, and granules. Follow manufacturer’s directions for application. Treat plants with Bt in the afternoon or evening, since it breaks down in UV light. Apply Bt at the first sign of worm eggs. Once the pests hatch and ingest the chemical, they are paralyzed, unable to eat, and die.
  
• Apply oils. Use neem oil or insecticidal soap once a week and after rain.
  
• Apply other controls. Treat plants with Spinosad,
  a natural, broad-spectrum insecticide made from soil microbes. Or treat plants with the insecticide Sevin every 5-7 days when fruit begins to set (worms are untouchable once they get inside tomatoes).
  

Find out all kinds of other information about tomato fruit worms on this page.

Good luck and happy gardening!
Your friends at Tomato Dirt