Mustard greens-Imported cabbageworm

Pieris rapae

Pest description, crop damage and life history

See:

Pest monitoring The following information is from California but is generally applicable in the Pacific Northwest: Cabbageworms can be monitored at the same time as cabbage loopers. Sample 25 plants selected randomly throughout the field. Although treatment levels combine the two species, cabbageworms may be harder to find because of their smaller size and their inconspicuous coloring. Look for small larvae and eggs on the undersides of leaves. Larger worms feed toward the center of the plant, often near the midribs of leaves. Good clues to cabbageworm presence include their greenish brown fecal pellets, or many white cabbage butterflies fluttering around the field (check for eggs in a few days).

Base treatment on numbers of healthy larvae present. Treat seedlings or small plants if populations of medium-size to large caterpillars are high enough to stunt growth. Prior to heading, well-established plants do not need to be treated unless you find more than nine small to medium-size larvae per plant.

Management-biological control

Natural enemies can assist significantly in the control of imported cabbageworm. Important parasites include the pupal, larval, and egg parasites in the Trichogramma genus, as well as tachinid flies. Timely mass releases of commercially available trichogramma during peak flight can be an effective control agent. Viruses and bacterial diseases are also sometimes important control factors in the field.

Where possible, use Bacillus thuringiensis (Bt) to avoid adverse impact on natural enemies. Bt is very effective against imported cabbageworm, especially when applied to young (early-instar) caterpillars.

Management-cultural control

Make new plantings as far as possible from those of the previous year. At the end of the year, harvest crops without delay. Plowing under or destroying plant residues at this time eliminates an important food source for the overwintering generation of cabbageworms.

Management-chemical control: HOME USE

  • azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
  • Bacillus thuringiensis var. kurstaki (Btk)-Some formulations are OMRI-listed for organic use.
  • bifenthrin
  • carbaryl
  • cyfluthrin
  • lambda-cyhalothrin
  • malathion
  • permethrin
  • pyrethrins-Some formulations are OMRI-listed for organic use.
  • spinosad-Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin

Management-chemical control: COMMERCIAL USE

  • alpha-cypermethrin (Fastac EC) at 0.014 to 0.025 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.075 lb ai/a per season.
  • Bacillus thuringiensis (Javelin) at 0.12 to 1.5 lb/a. PHI 0 days. REI 4 hr. Acts slowly; may need multiple applications. Add an appropriate spreader-sticker to enhance control. Most effective on small larvae. Some formulations are OMRI-listed for organic use.
  • beta-cyfluthrin (Baythroid XL) at 0.013 to 0.019 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a per season.
  • beta-cyfluthrin/imidacloprid (Leverage 360) at 0.07 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a beta-cyfluthrin or 0.2 lb ai/a imidacloprid per season.
  • bifenthrin (Brigade 2EC) at 0.033 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.4 lb ai/a per season.
  • bifenthrin/imidacloprid (Brigadier) at 0.06 to 0.095 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Limit 5 treatments after bloom. Do not exceed 0.24 lb ai/a imidacloprid and 0.5 lb ai/a bifenthrin.
  • bifenthrin/zeta-cypermethrin (Hero) at 0.04 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.45 lb ai/a per season.
  • Burkholderia spp. (Venerate XC) at 1 to 8 quarts/a product. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • carbaryl (Sevin 4F) at 1 to 2 lb ai/a. PHI 14 days. REI 12 hr. Retreatment interval 7 days. Limit 4 treatments. Do not exceed 6 lb ai/a per season.
  • chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/a at plant, drip or foliar. PHI 3 days. REI 4 hr. Limit 4 treatments per year. Retreatment interval 3 days foliar, 10 days drip. Do not exceed 0.2 lb ai/a per season.
  • chlorantraniliprole/thiamethoxam (Voliam Flexi) at 0.1 to 0.172 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season.
  • Chromobacterium subtsugae (Grandevo) at 0.3 to 0.9 lb ai/a per 100 gal. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • cyantraniliprole (Exirel) at 0.045 to 0.088 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 5 days. Do not exceed 0.4 lb ai/a per year.
  • cyclaniliprole (Harvanta 50SL) at 0.036 to 0.054 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 5 days. Limit 3 treatments. Do not exceed 0.22 lb ai/a per year.
  • cyfluthrin (Tombstone) at 0.025 to 0.038 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.2 lb ai/a per season.
  • cyfluthrin/imidacloprid (Leverage 2.7) at 0.08 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.17 lb ai/a cyfluthrin or 0.24 lb ai/a imidacloprid per year.
  • cypermethrin (Holster) at 0.05 to 0.1 lb ai/a. PHI 1 day. REI 12 hr. Allow at least 7-days between applications. Do not exceed 0.4 lb ai/a per season.
  • emamectin benzoate (Proclaim) at 0.0075 to 0.015 lb ai/a. PHI 14 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.09 lb ai/a per season. Do not graze.
  • esfenvalerate (Asana XL) at 0.05 lb ai/a. PHI 7 days. REI 12 hr. Do not exceed 0.2 lb ai/a per season.
  • indoxacarb (Avaunt) at 0.045 to 0.065 lb ai/a. PHI 3 days. REI 12 hr. Retreatment interval 3 days. Do not exceed 0.26 lb ai/a per season.
  • malathion (Malathion 8) at 1.0 lb ai/a. PHI 7 days. REI 12 hr. Limit 3 treatments. Retreatment interval 5 days.
  • methomyl (Lannate SP) at 0.45 to 0.9 lb ai/a. PHI 10 days. REI 48 hr. Do not exceed 3.6 lb ai/a per season. Limit 8 treatments per season.
  • methoxyfenozide (Intrepid 2F) at 0.06 to 0.12 lb ai/a for early-season application; at 0.12 to 0.16 lb ai/a for mid- to late-season application or heavy infestation. REI 4 hr. PHI 1 day. Adding adjuvant improves performance. Do not exceed 1 lb ai/a per season.
  • spinetoram (Radiant SC) at 0.039 to 0.078 lb ai/a. PHI 1 day. REI 4 hr. Retreatment interval 4 days. Do not exceed 0.266 lb ai/a per season. Limit 6 treatments per season.
  • spinosad (Success, Entrust SC) at 0.047 to 0.09 lb ai/a. PHI 1 day. REI 4 hr. Do not exceed 0.45 lb ai/a per crop. Limit 6 treatments per season. Entrust SC is OMRI-listed for organic use.
  • tebufenozide (Confirm 2F) at 0.09 to 0.12 lb ai/a for early season; 0.12 lb ai/a for mid to late season. PHI 7 days. REI 4 hr. Do not exceed 0.12 lb ai/a per application or 0.63 lb ai/a per season. Retreatment interval 10 days. Use of a spreader-binder is recommended.
  • thiamethoxam/chlorantraniliprole (Durivo) at 0.195 to 0.257 lb ai/a applied to the soil. PHI 30 days. REI 12 hr. Do not exceed 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season.
  • zeta-cypermethrin (Mustang) at 0.028 to 0.05 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.3 lb ai/a per season.