Pests & diseases › Tomato Hornworms

Tomato Hornworms

Huge (4-inch) bright green caterpillars with a horn on the rear. Strip tomato plants overnight.

Symptoms

  • Entire branches stripped of leaves
  • Black-green frass (droppings) on leaves below
  • Chewed green tomato fruit
  • Spot the huge caterpillar by careful inspection — they hide in plain sight

Lifecycle

Adult is the impressive hawk/sphinx moth. One or two generations per year.

What to do

  • Hand pick (you may want gloves — they grip hard)
  • DROP any caterpillar carrying white rice-grain cocoons on its back — those are parasitic wasps, leave them to hatch
  • Bt spray on smaller caterpillars
  • Spinosad

If it's bad

  • Carbaryl (Sevin) as last resort

Stop it coming back

  • Till soil in autumn to expose overwintering pupae
  • Plant dill, basil, marigold nearby (deterrents and trap crops)

Crops it goes for

Plan the plot, track every sowing, cook the harvest

Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.