Suhas Vyavhare & Katelyn Kesheimer, Texas A&M AgriLife Extension
It’s go time for the cotton planters on the Texas High
Plains. Planter wheels are turning throughout the region with clouds and patchy
rain loomed in the forecast. There has been some early planting underway and we
already are seeing some emerged cotton. Wireworms will be one of the first
pests you will see in the Texas High Plains cotton.
The wireworm adults (click beetles
and darkling beetles) become active in early spring and lay their eggs in the
soil in clusters. The adults, as well as the larvae produced from the late
summer and fall egg-lays, overwinter in the soil in leaf litter, stubble, or
other suitable habitats. Wireworms attacking cotton tend to be most severe
following grains crops, especially sorghum, fallow or weedy ground, or in
reduced-tillage systems.
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| Click beetle |
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| Darkling beetle |
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| Wireworm larva |
Most damage is inflicted by larvae,
although some darkling beetle species can girdle or clip seedling cotton off at
the soil surface much like a cutworm. The larvae damage cotton by feeding on
the root, hypocotyl (stem of the germinating seedling), and cotyledon (seed
leaves) of plants before emerging from the soil. Root feeding can kill plants, but usually
results in stunting. The most severe damage occurs when the hypocotyl is
severed resulting in plant death and stand reduction.
Planting shallow and under warm conditions often allow cotton seeds to
germinate rapidly and for plants to outgrow wireworms. From planting to 4-5 leaf
cotton, darkling beetle adults should be watched for invading cotton from
pastures, weedy areas, and corn and sorghum stubble. These beetles are only a
threat if they cut off the seedling plants resulting in stand reduction. Treat
for wireworm adults only when
encountered in large numbers, plant clipping is evident and unacceptable stand
reduction probable. Insecticidal seed treatments are the most effective means
of preventing wireworm damage. More information on wireworm damage and control
tactics can be found at: http://lubbock.tamu.edu/files/2017/05/Wireworms_ENTO-068.pdf
