Biological seed treatment
- Also known as
- seed treatment, seed-applied biological
A biological seed treatment is a product containing beneficial microorganisms or biologically derived substances that is applied to seed before planting, so that the organisms or compounds are in place as the seed germinates and roots begin to grow.
What is a biological seed treatment?
Seed treatment means coating seed with a product before planting. Chemical seed treatments, mainly fungicides and insecticides, protect seedlings from early pests and diseases. A biological seed treatment instead delivers living beneficial microorganisms, such as rhizobia, Bacillus or Trichoderma, or biologically derived compounds. Because the treatment travels with the seed, the organisms are right where the first roots emerge.
What biological seed treatments do
Depending on the product:
- Supply nitrogen-fixing bacteria to legumes, the most established use; see microbial inoculant.
- Promote early root growth and vigor.
- Improve nutrient availability, for example through phosphorus solubilization.
- Suppress seedling diseases by competition or antimicrobial activity.
How they are applied
- Commercially, by the seed company or a treating facility, often together with chemical treatments.
- By a dealer or retailer shortly before sale.
- By the grower, including as planter-box products; see box-applied biological.
What affects performance
- On-seed survival. Living organisms decline over time on seed, especially in heat and dry conditions. Products specify planting windows after treatment.
- Compatibility. Some chemical seed treatments, and the solvents or carriers in them, can harm microbes. Manufacturers publish compatibility guidance.
- Dose. Labels specify the number of live organisms, usually as colony-forming units, to be delivered per seed or per unit of seed.
- Field conditions after planting, which affect whether organisms colonize the roots.
Seed treatment vs. in-furrow
Seed treatments put a small, concentrated dose directly on the seed. In-furrow applications place a product in the seed furrow at planting, allowing higher rates and avoiding contact with chemical seed treatments, but requiring planter equipment. Some biological products are offered in both forms.
Frequently asked questions
It depends on the product and conditions. Many rhizobia seed treatments specify a limited window after treatment; some newer formulations extend it. Always follow the label.
Often yes, but not always. Compatibility depends on the specific products, and manufacturers publish lists of compatible treatments and the maximum time between treatment and planting.
Sources
- Seed treatment and inoculation guides, Land-grant university extension
- Microbial inoculants in agriculture, Peer-reviewed reviews