Plant Diagnostic Database

Imported Cabbage Worm  (Pieris rapae)

                       

importedcabbagewormlarva

importedcabbagewormadult

importedcabbagewormpupa

importedcabbagewormegg

 

 

 

 

 

                                                                                                                                                                                              
Hosts:

Broccoli and other cabbage family plants (cabbage, cauliflower, brussels sprouts, kohlrabi, kale), lettuce, radish, rhubarb.

Description:
 Larvae are velvety-green with a faint yellow stripe up to 1-1/4 inch long. They are very slow moving. Adults are white butterflies.
Life Cycle:
The adult butterflies are usually active during the months of May and June. Larvae hatch and begin feeding, usually on the outside leaves.       
Controls:
Cultural:
Biological:

Grow resistant varieties if available. Heavy rainfall helps to decrease worm populations, so overhead irrigation or directed sprays of water can somewhat decrease population levels in the early stages.

Start checking for these worms as soon as you begin to see adults flying around your plants. Spray with Bt(Bacillus Thuringensis) when you find 1 worm per 2 plants. It is most effective on newly hatched, smaller (1/2 - ¾") worms.   

Mechanical:

Chemical:

Cover plants with floating row cover(remay) before butterflies are present.

Spinosad or pyrethrin can be sprayed on larva.

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