Seed treatments are an important part of wheat production in Kansas. The K-State publication MF2955, Seed Treatment Fungicides for Wheat Disease Management, is available at http://www.ksre.ksu.edu/bookstore/pubs/MF2955.pdf.
This publication provides information about setting seed treatment priorities, considerations for seed treatment success, a key to common seed treatment active ingredients, and a list of some of the more common seed treatments labeled for use in Kansas.
Most fungicide seed treatments protect against several seed-borne diseases (common bunt, loose smut, flag smut) and seedling diseases that may result in poor emergence or damping off. Additionally, fungicide seed treatments should be a priority if the seed is saved from fields with Fusarium head blight.
Additional considerations for seed treatments:
Fungicide seed treatments help keep seed-borne diseases such as smuts and bunts in check. Loose smut and common bunt, sometimes called, “stinking smut”, can be controlled very effectively with most commercial treatments that include an ‘azole’ fungicide (think tebuconazole or difenoconazole). Some regions of the state have struggled with these diseases in recent years. If you are planning to keep seed that is known to have common bunt or loose smut, it is critical to use a fungicide seed treatment to avoid more severe problems in the future.
Seed production fields are a top priority for fungicide seed treatments. These fields have a high value, and investments in seed treatments here help prevent the introduction and development of seed-borne diseases on your farm. Due to the high value of the seed produced, even small yield increases can justify the use of seed treatments.
Seed treatments can aid stand establishment when planting wheat after soybean harvest, even on seed that has high test weight and good germination. Planting wheat late into cool, wet soils often delays emergence and reduces the tillering capacity of wheat seedlings. This reduced tillering capacity diminishes the plants' ability to compensate for stand loss and maintain yield potential.
Some fungicide seed treatments also suppress the fall development of foliar diseases. For example, treatments containing tebuconazole and difenoconazole provide some protection against fall infections of powdery mildew, leaf rust, and Stagonospora leaf blotch. It is important to note that most seed treatment fungicides will provide a maximum of 30-45 days of control. A seed treatment will not prevent the disease from becoming reestablished in the spring, and foliar fungicide applications may still be required to protect the yield potential of the crop.
Things to remember
As with most things in agriculture, producers must balance the possible benefits against the cost. Some growers also prefer not to risk having leftover treated seed to deal with at the end of planting. If the seed is treated on-farm, pay close attention to thoroughly covering the seed. Incomplete coverage can reduce the efficacy of the seed treatment.
There are many different seed treatments available for wheat. Although most seed treatment ingredients are fungicides, some will also contain insecticides. Each ingredient targets a slightly different spectrum of disease-causing fungi or insect pests. Therefore, many commercial formulations include combinations of ingredients that provide a broader spectrum of protection.
Kelsey Andersen Onofre, Extension Plant Pathologist
andersenk@ksu.edu
Romulo Lollato, Extension Wheat Specialist
lollato@ksu.edu