Tomatoes: Dealing with Pests

Pest Symptoms Control
Nematodes (microscopic round worms)

  • Generally attack the roots and cause decrease in root volume and a general weakness in the plant.
  • Can make the plants susceptible to other disease.
  • Nematodes may transmit viral disease.
  • Plants appear unthrifty
    • Stunted
    • Wilt prematurely and recover slowly after watering.
    • Can look like the plants aren’t getting enough nutrients (since the root mass is reduced, this is actually true.)
    • Fruit may color early.
  • Rotate crops to reduce multiplication of nematodes in the soil by removing the nutrient source.
  • Grow nematode resistant varieties of tomatoes (labeled N)
  • Add organic material to soil since nematodes thrive in sandy soil.
  • Plant marigolds, chrysanthemums or dahlias close to tomatoes.
Cutwormlarvae of caterpillars
  • Seedlings appear to be cut off
  • Remove weeds long before planting
  • Place a collar around the base of the stem. Collars can be made of wax paper, tin cans, plastic soft drink bottles.
  • Mulch soil well
  • Leaf yellowing
  • Plants appear shiny and feel sticky due to the excrement of aphids called honeydew
  • Main vectors (transmitters) of viral diseases.
  • Plant basil among the tomatoes because basil produces chemicals that repel aphids. Also tastes great in a tomato basil salad or tomato sauce.
  • Insecticidal soaps may also be used.

  • About 1 mm long and are dark brown to pale yellow.
  • Adults have two pairs of narrow wings.
  • Damage is minimal
  • Transmit viral diseases
  • Basil repels thrips
  • Use plant oils which stick to insects and slow their movement.
  • Hang sticky traps among the plants.
Tomato bollworm or fruitworm

  • Colors range from green to yellow to pinkish red to chocolate brown
  • Has 4 pairs of legs on abdomen (looper has only 2 pair of legs)
  • Tunnels into fruit and causes it to rot
  • Pesticides not recommended
  • Natural predators include spiders, ants, ladybugs, and birds.
Whiteflysmall(1 mm) and white
  • Feed on plant and also secrete honeydew
  • Sooty mold fungus can stick to honeydew
  • More of a problem in greenhouses than in the outdoors.
  • Natural predators include spiders, ants, ladybugs, and birds.
  • Pesticides not recommended.
Stink bugsgreen or brown and shield-shaped and emit a pungent smell when disturbed.
  • Dark pinpricks surrounded by a light discoloration on green fruit.
  • Spots may remain green or turn yellow as fruit ripens.
  • Cavities may form under damaged skin.
  • Keep area weed free
Spider mite
  • White-yellow speckling on leaf surface.
  • Decreased plant growth and death of plant
  • Problem in hot dry weather.
  • Frequently spray plants with water mist.
Fruit Fly
  • Small maggots in fruit.
  • Pick fruit regularly.
  • Do not leave fruit lying on the ground.
  • If infestation is a problem, pick green tomatoes and let ripen indoors.
  • Use fly-proof net.
  • Destroy plants by chewing stems at or close to ground level.
  • Look for cricket holes and fill with hot water.
Slugs and snails
  • Not much of a problem but will destroy ripe fruit.
  • Put collar made from plastic soft drink bottle or tin can around the stem.
  • Peck marks in fruit
  • Regular picking of fruit.