Agriculture: Lettuce Pest Management Guidelines

Saltmarsh Caterpillar

Description of the Pest

Early instars of the saltmarsh caterpillar can be found in various shades of yellow-brown with long, dark hairs. Older caterpillars are densely covered with black and red hairs and often have yellow stripes running lengthwise down their bodies. Adult moths have white wings with numerous black spots on the upper surface and yellow on the undersides.

Damage

Saltmarsh caterpillar is rare, but serious pest of lettuce and other crops in Low Desert areas of Southern California. Larvae feed on leaves and cause economic losses.

Management

To prevent saltmarsh caterpillar infestation in lettuce:

  • Monitor adjacent fields for infestations. Saltmarsh caterpillars will increase their numbers on neighboring crops such as cotton, beans or on weeds and then move into a lettuce field.
  • Place a barrier such as a 6-inch-high strip of heavy aluminum foil set on its edge in the soil, or a shallow irrigation ditch filled with water to minimize migrating saltmarsh caterpillars.
Text Updated: 04/17