Agriculture & Natural Resources

Cabbage Insect Scouting Guidelines

1. General Scouting Pattern: 5 consecutive plants in 10 locations for up to 50 acres; add one additional sampling location for every 10 acres of land; V- shape should be used to cover entire field

2. Before Heading: Be sure to check for insects feeding deep in the whorl

Pest
When to Sample
Action Threshold
Thrips Spring Planted; From transplanting/plant emergence to harvest 20 % plants infested – treat before thrips move deep into wrapper leaves
Aphids Generally Spring Planted; Seedling Stage Plants Rarely a problem in our area; 10 % of the plants with one or more colonies per plant
Imported Cabbageworm Spring Planted Cabbage; Seedling Stage to Harvest; overwinters in the Mid-Atlantic Pre-Heading: 20% plants infested
Heading to Harvest: 5% plants infested
Cabbage looper Generally a pest of fall planted cabbage; migratory pest; Can attack spring planted fields in June if migrates early to our area Pre-Heading: 20% plants infested
Heading to Harvest: 5% plants infested
Diamondback moth larva Spring and Fall Planted Fields; Significant problem with fall plantings; overwinters in the Mid-Atlantic Feeding in the heart preheading: 5 % infested
Feeding on wrapper leaves preheading: 20% infested plants
Heading to Harvest: 5 % infested plants

University of Delaware IPM Program
Joanne Whalen – Extension IPM Specialist

Bill Cissel – Extension IPM Agent