Sugar beet-Saltmarsh caterpillar

Estigmene acrea

Pest description and crop damage "Woolly bear" caterpillars up to 2 inches long, covered by long, red-brown hairs. They are seen especially in late season but rarely are an economic problem.

Scouting and thresholds No formal economic thresholds exist for saltmarsh caterpillar insecticide treatment decisions.

Management-biological control

  • Bacillus thuringiensis aizawai (XenTari - live spores of an insect-killing bacterium)-See label for rates. PHI 0 days. Biological insecticide most effective against newly hatched larvae. No contact action; larvae must eat treated leaves. Use a spreader-sticker. REI 4 hr. Some formulations are OMRI-listed for organic use.
  • Bacillus thuringiensis kurstaki (Biobit HP, Crymax, Deliver, Dipel DF, Javelin WG, and others - live spores of an insect-killing bacterium)-See label for rates. PHI 0 days. REI 4 hr. Biological insecticide most effective against small, newly hatched larvae. No contact action; larvae must eat treated leaves. Use a spreader-sticker. Some formulations are OMRI-listed for organic use.

Management-chemical control

  • azadirachtin (Azatin O) at 0.025 to 0.1 lb ai/a. Foliar application against larvae.
  • azadirachtin + pyrethrins (Azera) at 0.0125 to 0.025 lb ai/a, and up to 0.044 lb ai/a under extremely heavy infestation. Dilution in a minimum of 30 gal of water per acre is recommended for conventional equipment. May be applied by air at the rate of 0.0125 to 0.025 lb ai/a in a minimum of 25 gal of water. Do not repeat more than every 5-7 days. OMRI-listed for organic use.
  • esfenvalerate, (Asana XL, S-fenvaloStar, Zyrate) at 0.03 to 0.05 lb ai/a. PHI 21 days. Apply as necessary but not more than 0.15 lb ai/a per season. Apply with ground or air equipment using enough water (at least 2 gal/a) to cover uniformly.
  • methoxyfenozide (Intrepid 2F, Troubadour) at 0.12 to 0.25 lb ai/a. Apply at egg hatch or when signs of feeding occur. PHI 7 days.
  • pyrethrins (Lynx EC 1.4, Lynx EC 5.0, PyGanic EC 1.4, Tersus)-See label for rates. REI 12 hr. PHI 0 days. Some formulations are OMRI-listed for organic use.