See tips Florida ranchers need to know to scout for armyworms in Florida grazing pastures in order to combat this pest.

Armyworms are a handful of destructive caterpillar species that invade Florida grazing pastures—Fall Armyworm (Spodoptera frugiperda), Southern Armyworm (Spodoptera eridania), and Beet Armyworm (Spodoptera exigua). According to a UF/IFAS blog, they are “a significant concern for cattle ranchers.” The adult moths—brown with a dark stripe on their forewings—can lay up to 1500 eggs in a few weeks. See tips for scouting for these Florida pests.

Scouting for Armyworms

The blog shares these tips:

  • “Armyworms prefer well fertilized grasses and may feed on a variety of forages, causing severe damage to pastures and hayfields. Armyworms can infest hundreds of plant species, including the following forages:
    • Bermudagrass (Cynodon dactylon)
    • Limpograss(Hemarthria altissima)
    • Bahiagrass (Paspalum stelatum)
    • Aeschynomene (Aeschynomene americana)
    • Rhizoma perennial peanut (Arachis glabrata)
    • Sunn hemp(Crotalaria juncea)
    • Sorghum (Sorghum bicolor [L.] Moench)
    • Annual ryegrass(Lolium perenne L. ssp. Multiflorum) and other cool-season forages”
  • The best times to scout are “late Summer to Early Fall (August-October): Peak activity typically occurs after heavy rains or storms.”
  • Armyworms prefer “new growth; Scout areas with lush, green grass, as these are most attractive to armyworms.”
  • The caterpillars are “green to brown, often with dark stripes; Up to 1.5 inches long;” and have and “Inverted “Y” shape on the head.”
  • “Inspect fields weekly during high-risk periods.”
  • Look for signs of feeding damage or caterpillars themselves. The last 2-3 days of the caterpillar stage, 80% of leaf consumption occurs causing quick pastures destruction.”
  • “Scout in the early morning and late afternoon when armyworms are most active.”
  • “Waiting for signs of birds in a pasture could be too late to avoid damage.”

Read our follow-up blog on management options for controlling armyworms.

Griffin Fertilizer is committed to helping both growers and ranchers make sound agronomic and economic decisions in order to maximize the health of their grove and pasture. As a full-service custom dry & liquid fertilizer blender and crop protection product distributor, we will continue our mission to further advance Florida agriculture. For questions -or concerns about your farm or pasture, contact us and one of our team will be in touch.