How to Control Leaf Miners on a Tomato Plant

Overview

Leaf miners are the larvae of small flies that lay eggs in the leaves of tomato plants. When the eggs hatch, the larvae eat the interior layer of the leaves, leaving trails called mines. Leaf miners can cause leaves to die and drop off. Though the larvae only feed on the tomato leaves for two weeks, seven or eight generations of leaf miners can feed each summer. Heavy infestations can kill tomato plants.

Step 1

Monitor plants for damage. If only a few leaves are damaged, pick off these leaves and destroy them. If one or two plants are affected, the best control is to uproot and destroy these plants, which will destroy any leaf miner larvae and eggs on the plants.

Step 2

Spray the leaves of affected tomato plants with an organic insecticide containing spinosad. This insecticide is approved for use on organic crops, and it won't harm beneficial insects.

Step 3

Hang flypaper in greenhouses to capture leaf miner flies before they have a chance to lay their eggs.

Step 4

Purchase parasitic wasps Diglyphus begini or Chrysocharis parksi and release them into the garden. The University of California Agricultural and Natural Resources department recommends these wasps as effective biological controls against leaf miners.

Tips and Warnings

  • Avoid use of broad-spectrum insecticides, which can destroy beneficial insects, including natural enemies of leaf miners.

Things You'll Need

  • Garden sprayer
  • Organic insecticide containing spinosad
  • Fly paper
  • Parasitic wasps

References

  • University of California: Tomato Leaf Miners
  • University of Missouri Extension: Managing Indoor Plant Pests

Who Can Help

  • Arizona Master Gardener: Pests of Gardens
Keywords: leaf miners, tomato pests, beneficial insects

About this Author

Cynthia James is the author of more than 40 novels and her nonfiction work has appeared in publications ranging from Modern Bride to Popular Mechanics. A graduate of Sam Houston State University, she has a degree in economics. Before turning to freelancing full time, James worked as a newspaper reporter, travel agent and medical clinic manager.