Diamondback Moth - Plutella xylostella                              Alton N. Sparks Jr., The University of Georgia, www.ipmimages.org HOSTS: Cabbage family plants (cabbage, cauliflower, brussels sprouts, broccoli, kohlrabi, kale). DESCRIPTION: Larvae are greenish-yellow, 5/16 inch long, pointed at both ends and covered with fine black hairs. LIFE CYCLE: Adult moths overwinter under cover; they emerge early in spring to mate and lay eggs. Larvae hatch to feed on the undersides of outer leaves, then pupate in a loose cocoon. The cycle from eggs to adults takes only 4-6 weeks. There are usually several generations per season. CONTROLS: Biological: Check plants weekly as soon as they are planted. Spray if you find 1 worm per 2 plants. Beauveria bassiana (mycotrol) reduced diamondback moth larvae on cabbage transplants in the field. Multiple applications improved performance. Bt is not particularly effective on this worm; use only when larvae are small and add 1-2 Tblsp/gal of insecticidal soap. Wasps parasitize these worms. Spiders and damsel bugs feed upon both eggs and young. Chemical: Neem.
Missoula County Extension Office; Missoula, Montana 59808 - Updated for 2006