1. Insect
  2. Agronomic Crops
  3. Field and Silage Corn Pests

Field and silage corn-Corn earworm

  • Facebook logo
Image related to Field and silage corn-Corn earworm
Corn earworm
Helicoverpa zea Boddie
Adult
© Ken Gray Insect Image Collection
Image related to Field and silage corn-Corn earworm
Corn earworm
Helicoverpa zea Boddie
Immature showing damage
© Ken Gray Insect Image Collection
Image related to Field and silage corn-Corn earworm
Corn earworm
Helicoverpa zea Boddie
Immature showing damage
© Ken Gray Insect Image Collection

Helicoverpa zea

Pest description and crop damage Adult moths measure up to about 19 mm in length, with a wing span of 25 to 38 mm and are from olive green, to tan, to dark reddish brown in color. Egg laying occurs singularly on fresh young foliage throughout corn growing season. Eggs are spherical with 12 or more ridges radiating from the top. Young larvae are greenish with brownish/black heads, with conspicuous black hairs on the body. Fully developed worms are about 38 mm long and range in color from pale green or pinkish to brown.

First-generation larvae may feed as "budworms," damaging leaf whorls and newly formed ears. As subsequent generations hatch throughout the growing season, larvae target the plant's ear tips and silks. Pheromone-baited cones or net traps can be placed around the field at corn ear height in early ear development for monitoring. Lures should be replaced every two weeks.

For a more comprehensive description of this pest, visit: https://www.uidaho.edu/extension/ipm/ag-pests/arthropods/corn-earworm

Management-biological control

Generalist predators and parasitoids, such as Triochogramma wasps can aid in suppression and control of corn earworm.

Management-chemical control

  • alpha-cypermethrin (Fastac CS) - at 0.011 to 0.025 lb ai/A. REI 12 hr. PHI 30 days grain and stover; 60 days forage. Retreatment interval 3 days. Do not exceed 0.075 lb ai/A per season. IRAC group 3.
  • Bacillus amyloliquefaciens D747 TGAI/bifenthrin (Ethos 3D, Ethos XB) at 0.04 to 0.2 lb bifenthrin ai/A. Do not exceed 0.3 lb bifenthrin on field corn per season. REI 12 hr. IRAC Group 3A insecticide, Group 44 fungicide.
  • beta cyfluthrin (Baythroid XL) at 0.013 to 0.022 lb ai/A (1.6 to 2.8 fl oz/A). PHI 0 days for green forage and 21 days for grain or fodder. REI 12 hr. Maximum 2.8 fl oz/A in 7-day interval. Do not exceed four applications or 0.088 lb ai/A per season. IRAC Group 3.
  • bifenthrin (Brigade 2EC, Sniper) at 0.033 to 0.1 lb ai/A (2.1 to 6.4 fl oz/A). PHI 30 days for harvest, grazing, or cutting for feed. REI 12 hr. Do not apply more than 0.3 lb ai/A per season. IRAC group 3A.
  • bifenthrin/chlorantraniliprole (Elevest) at 0.098 to 0.167 lb ai/A. REI 12 hr. PHI 30 days. No more than three applications per year. Do not apply more than a total of 0.2 lb ai/A of chlorantraniliprole and 0.3 lb ai/A of bifenthrin per year. Apply ELEVEST insect control when silking begins and repeat as necessary to maintain control. IRAC group 3A and 28.
  • bifenthrin/zeta-cypermethrin (Hero) at 0.04 to 0.1 lb ai/A (4.5 to 11.2 fl oz/A). PHI 30 days grain and stover; 60 days forage. REI 12 hr. Do not graze for 30 days after treatment. Do not exceed 0.1 lb ai/A at-plant application or 0.099 lb/A zeta-cypermethrin and 0.398 lb/A bifenthrin per year. IRAC Group 3A.
  • Burkholderia spp. (Venerate XC) bioinsecticide at 1 to 4 quarts/A. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • carbaryl (Sevin 4F) insecticide at 1 to 2 lb ai/A. PHI 14 days for forage or silage grazing, and 48 days for grain harvest. REI 24 hr. Do not exceed four applications or 8 lb ai/A per season. Latex-based formulations, such as Sevin XLR Plus, are less hazardous to bees.
  • chlorantraniliprole/lambda-cyhalothrin (Besiege) at 0.045 to 0.08 lb ai/A (5 to 10.0 fl oz/A). For control before larva bores into plant stalk or ear. PHI 21 days. REI 24 hr. Do not exceed 0.12 lb ai of lambda-cyhalothrin or 0.2 lb ai of chlorantraniliprole per acre per growing season. Retreatment interval 7 days. IRAC group 3 & 28 insecticide.
  • chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/A. PHI 14 days. REI 4 hr. Do not exceed 4 treatments nor 0.2 lb ai/A per season. Retreatment interval 7 days. IRAC Group 28 insecticide.
  • Chromobacterium subtsugae (Grandevo) bioinsecticide at 0.6 to 0.9 lb ai/A per 100 gal (2.0 to 3.0 lb product /A). PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • cyfluthrin (Tombstone) at 0.025 to 0.044 lb ai/A (1.6 to 2.8 fl oz/A). PHI 0 days for green forage and 21 days for grain or fodder. REI 12 hr. Retreatment interval 7 days. Do not exceed four applications or 0.175 lb ai/A per season. IRAC group 3A.
  • deltamethrin (Delta Gold) at 0.018 to 0.022 lb ai/A (1.5 to 1.9 fl oz/A). PHI 21 days for grain or fodder, or 12 days for forage or grazing. REI 12 hr. Do not apply more than 0.095 lb ai/A per season. 5 lb ai/A. PHI 21 days. REI 12 hr. Do not exceed 0.25 lb ai/A per season. IRAC Group 3.
  • esfenvalerate (Asana XL) at 0.03 to 0.05 lb ai/A (5.8 to 9.6 fl oz/A). PHI 21 days. REI 12 hr. Do not exceed 0.25 lb ai/A per season. IRAC Group 3.
  • gamma cyhalothrin (Declare) Group 3 insecticide at 0.0075 to 0.0125 lb ai/A. Effective prior to larvae entering the ear only. PHI 1 day for grazing and forage, or 21 days for fodder and silage. REI 24 hr. Do not exceed 0.06 lb ai/A per season. IRAC Group 3.
  • HZNPV (Gemstar LC)-Insecticidal virus product (biopesticide). OMRI-listed for organic use.
  • indoxacarb (Steward EC) at 0.059 to 0.11 lb ai/A. PHI 14 days grain, 1 day forage, fodder, silage. REI 12 hr. Limit 2 treatments. Do not exceed 0.22 lb ai/A per year. IRAC Group 22 insecticide.
  • lambda-cyhalothrin (Warrior II) at 0.015 to 0.025 lb ai/A. PHI 21 days. REI 24 hr. Do not apply more than 0.12 lb ai/A per season, 0.06 lb ai/A after silk initiation, or 0.03 lb ai/A after milk stage. IRAC Group 3 insecticide.
  • malathion (Drexel 5EC, Fyfanon 57EC, Fyfanon 8 lb Emulsion and several other formulations)-See label for rates. Rates may vary between formulations. PHI 7 days. REI 72 hr for detasseling, 12 hr for other activities. IRAC Group 1.
  • methomyl (Lannate SP) at 0.22 to 0.45 lb ai/A. PHI 21 days for ears, 3 days for forage, 21 days for fodder. Do not exceed 2.25 lb ai/A or 5 treatments per season. REI 48 hr. Retreatment interval 5 to 7 days. Restricted use pesticide. IRAC Group 1A insecticide.
  • methoxyfenozide/spinetoram (Intrepid Edge) at 0.188 to 0.281 lb ai/A. PHI 28 days. REI 4 hr. Do not exceed 0.625 lb ai methoxyfenozide and 0.125 lb ai spinetoram per acre per year. Limit 3 treatments. Retreatment interval 4 days except 2 days for silking. IRAC Group 5 and 18 insecticide.
  • permethrin (Ambush 25W) at 0.1 to 0.2 lb ai/A. PHI 0 days for forage; 30 days for grain harvest or fodder. REI 12 hr. Allow 6 days between treatments. Do not apply more than 0.6 lb ai/A per season. IRAC Group 3.
  • spinetoram (Radiant SC) Group 5 insecticide at 0.023 to 0.047 lb ai/A. PHI 3 days forage or fodder; 28 days grain. REI 4 hr. Do not exceed 0.125 lb ai/A per year. Do not exceed 3 treatments. Retreatment interval 4 days.
  • spinosad (Success, Entrust SC) at 0.023 to 0.094 lb ai/A. PHI 28 days grain or fodder; 7 days forage. REI 4 hr. Do not exceed 0.188 lb ai/A per season. Entrust SC was found effective at suppressing larvae when treated at 4-day intervals. Some organic formulations. IRAC group 5.
  • tebuconazole/lambda-cyhalothrin (Crossover) at 0.14 to 0.16 lb ai/A. PHI 21 days fodder and silage. REI 24 hr. Retreatment interval 7 days. Do not exceed 0.48 lb ai/A tebuconazole or 0.12 lb ai/A lambda-cyhalothrin per season. IRAC group 3.
  • zeta-cypermethrin (Mustang, Mustang MAXX) at 0.022 to 0.05 lb ai/A (Mustang) 0.011 to 0.025 lb ai/A (Mustang MAXX). PHI 7 days for grain, stover and forage. Do not exceed 0.2 (Mustang) lb ai/A and 0.01 lb ai/A (Mustang MAXX) per season. REI 12 hr. Group 3A insecticide Retreatment interval 3 days.