Wireworm reduced my stand even though I seed treated. What can I do?
We are far enough into the season that impacts of wireworms are present and visible. I recently had a couple conversations about wireworm impacts on fields that have been seed treated to suppress wireworm. These wireworm seed treatments work through ingestion by the wireworm. This means that the wireworm must feed on the seedling before it is impacted. This feeding will kill some seedlings. If the wireworm population is high enough, it will cause noticeable reductions in your plant stand. This can lead to variable maturity, more opportunity for weed growth, as well as yield reductions.
One way to combat this is to assess the wireworm damage. Conduct plant stand counts in wireworm problem areas versus non-problem areas. This will give you an idea of what percentage your stand is being reduced by feeding. Wireworms can live in the soil for five to seven years and they don’t move far, other than up and down in the soil profile. Because of this, you can assume that the damage inflicted this year will be similar in following years. If you find that you have a 15% reduction in plant stand due to wireworm feeding, increase seeding rates in those problem areas by 15% the following year.