A wireworm-infested field in Natchitoches. Stunted growth and uneven stands. (Photo by J. Villegas)
Louisiana's spring season has been marked by unseasonably cold weather, which has slowed the growth and emergence of corn already in the ground. This has led to an upsurge in soil-borne insect problems that are becoming more apparent as producers and agricultural consultants survey their fields. This week, I looked at a cornfield in Natchitoches with Steve Schultz, that was severely affected by wireworms, a persistent and damaging pest that can wreak havoc on several crops.
Wireworms are the larvae of click beetles, which are brown or black beetles that are about 1/2 inch long. These larvae are slender, brown, or yellowish-brown, and have rigid, cylindrical bodies with a wire-like appearance. They can survive for several years in the soil, feeding on plant roots and other organic matter. Depending on the species, it takes 3-5 years before the larvae turn into adults.
Wireworms were found after up-rooting severely stunted corn plants. (Photos by J. Villegas)
Wireworms can cause significant damage to corn by feeding on the roots, leading to stunted growth, reduced yield, and even plant death. This can be particularly problematic in seedling corn, as wireworm feeding can reduce the plant's ability to absorb water and nutrients, making them more susceptible to stress and disease. There are no rescue treatments for wireworm infestation, but as the season progresses and corn plants put on more roots, the crop becomes less susceptible to wireworm feeding.
Wireworm damage: stunted, uneven stands and feeding injury at the base of the roots. (Photos by Steve Schultz).
One of the biggest obstacles in managing wireworms is their long life cycle and ability to survive in the soil for several years. Therefore, controlling wireworms requires multiple years of implementing control measures to be effective. Insecticidal seed treatments are a reliable option, but environmental factors such as excessive moisture may hinder their effectiveness by causing the insecticide to move out of the root zone, leaving seedlings susceptible to wireworms. Crop rotation can disrupt the pest's life cycle and potentially reduce their populations, but it may take several years to achieve the desired results. Tillage is another option that can disrupt wireworm habitats, but it may not be suitable for all farming operations (e.g. no-till or reduced-till production systems). Producers should evaluate these strategies when designing a comprehensive wireworm management plan that suits the situation of their fields.
The LSU AgCenter and the LSU College of Agriculture