Pasture webworm

Hednota pedionoma

Overview:

Hednota pedionoma, commonly known as the Tropical Turf Webworm, is a moth species belonging to the family Crambidae. It is a turfgrass pest that can cause damage to lawns and grassy areas in tropical and subtropical regions.

Detailed Appearance:

  • Adult moths are small, with a wingspan ranging from 15 to 20 millimeters.
  • The forewings of the moth are typically brown or gray with indistinct markings.
  • Larvae (caterpillars) are often light green or yellow-green with dark head capsules.

Life Cycle:

  • The life cycle includes egg, larva, pupa, and adult stages.
  • Female moths lay eggs on or near grasses.
  • Larvae hatch and feed on grass blades and stems.
  • Mature larvae pupate in the soil.
  • Adults emerge from pupae, and the cycle repeats.

Identification of Crop Infestation:

  • Presence of small caterpillars on grass blades, creating silk webbing.
  • Damage appears as patches of brown or dead grass in affected areas.
  • Feeding occurs primarily at night, and young larvae may skeletonize leaves.

Management Strategies:

  • Cultural Controls:

    • Maintain healthy turf through proper irrigation, fertilization, and mowing practices.
    • Regularly inspect the lawn for signs of infestation.

  • Biological Controls:

    • Encourage natural predators such as ground beetles, spiders, and predatory insects.
    • Birds, including insectivorous species, can help control webworm populations.

  • Mechanical Controls:

    • Handpick or physically remove caterpillars and affected grass.
    • Use a high-pressure water hose to dislodge caterpillars and webs.

  • Bacterial Insecticides:

    • Apply bacterial insecticides containing Bacillus thuringiensis var. kurstaki (Bt).
    • Bt is effective against caterpillars and has low toxicity to non-target organisms.

  • Chemical Controls:

    • Apply insecticides labeled for turfgrass webworm control when necessary.
    • Follow recommended application rates and timings.

  • Insecticidal Soaps and Oils:

    • Insecticidal soaps or horticultural oils can be effective against young larvae.
    • These products have minimal impact on beneficial insects.

  • Preventive Measures:

    • Consider preventive treatments during peak periods of webworm activity.
    • Monitor and treat as needed based on local climate and pest prevalence.

Implementing a combination of these management strategies is crucial for effectively controlling Tropical Turf Webworm infestations and minimizing damage to lawns and turfgrass. Regular monitoring, early intervention, and a well-balanced approach contribute to successful pest management in affected areas.