By Blake Jackson
Now is an essential time to evaluate corn and soybean fields for potential fungicide applications, given the variable weather conditions across Pennsylvania.
While temperatures and degree-day accumulations are generally above average, rainfall patterns differ significantly by location.
Despite adequate rainfall during the primary planting period, many areas experienced abnormally dry conditions in June.
As corn and soybeans enter critical growth stages, Penn State Extension plant pathologists Alyssa Collins and Paul Esker recommend considering foliar fungicide applications to combat key foliar diseases.
The necessity of these applications in 2024 varies by location and requires continuous monitoring through July and early August.
Deciding on fungicide application should follow an integrated pest management approach, which includes cultural practices like variety selection, crop rotation, tillage, and crop scouting. The e-book "Fungicide Use in Field Crops" and updated 2024 foliar fungicide efficacy guides for soybeans and corn provide valuable insights for making informed decisions.
In soybeans, fungicide applications are recommended at the R3 growth stage, where the pod is three-sixteenths inches long at the uppermost nodes on the main stem.
Research from 2005 to 2018 indicates an average yield response of 1.64 bushels per acre when fungicides are applied at this stage, especially with earlier planting dates and higher rainfall averages.
For corn, the most significant yield benefits from fungicide applications are seen at the VT to R1 growth stages. This timing, although requiring specialized and costly equipment, protects crucial tissues like the ear leaf and younger leaves.
In high disease-pressure situations, some farmers also apply a second treatment two to three weeks after VT.
Scouting for diseases like gray leaf spot or northern corn leaf blight in corn and frogeye leaf spot in soybeans is crucial in early to mid-July.
Consideration of the soybean variety or corn hybrid’s disease resistance, along with economic factors such as current commodity prices and application costs, is essential in determining the necessity and economic viability of fungicide applications.
Registration costs $10 and is appreciated by July 22. To register, visit extension.psu.edu/manure-management or call 877-345-0691.
Photo Credit: gettyimages-klosfoto
Categories: Pennsylvania, Crops, Corn, Soybeans