Corn seed treatment: what seed treatment does and what the label allows
A seed treatment protects against the target diseases, insects or other pests named in its directions. Registration review assesses both the treating pesticide and the treated seed, including uptake into seedlings and availability to exposed organisms.
The treated-article exemption applies when a registered pesticide protects the seed and what it becomes. The treating product must be registered for that seed crop, and distribution and use must follow its labeling.
Fungicides for seed treatment: contact and systemic fungicides matched to the pathogen
Contact protectants act on the seed surface and generally have a short residual. Captan, thiram and fludioxonil are examples used against susceptible seed- and soil-borne pathogens. Systemic fungicides enter the emerging seedling and act inside plant tissues. Mefenoxam and metalaxyl primarily target Pythium, a water mold.
Other systemic seed-treatment ingredients include azoxystrobin, carboxin, thiabendazole and trifloxystrobin. Triazole examples include difenoconazole, ipconazole, tebuconazole and triticonazole. These ingredients differ in their target range; select a registered formulation for the diagnosed problem. Fungicide seed treatments address susceptible fungal or water-mold diseases, while bacterial and viral diseases need other management measures.
On-seed treatment targets pathogens on the seed and those contacting the seed or young root in soil. In-furrow fungicide treats the soil and generally uses more active ingredient.
For biological seed treatment, match the microorganism or strain to the target pest; microbial active ingredients have specific target ranges. A microbial pesticide uses a bacterium, fungus, virus or protozoan as its active ingredient, while a plant-incorporated protectant is a pesticidal substance produced by a plant from introduced genetic material. For a Trichoderma proposal, identify the actual strain, formulation and labeled seed-crop use before choosing a biological seed treatment.
Soybean seed treatment: when a fungicide seed treatment may help
Damping-off is a major concern for early-planted soybean, and a fungicide seed treatment may be beneficial for early planting in cold, wet soils, in reduced-till and no-till fields, and for seed with a germination rate below 80% or low vigor. The most common seed and seedling rot fungi in Iowa are Rhizoctonia and Fusarium, the water molds Pythium and Phytophthora, and seed-borne Phomopsis. Mefenoxam and metalaxyl control the water molds, so a product for soybean needs a second active ingredient to cover the other soil-borne fungi.
Best seed treatment for wheat and seed treatment of coriander
There is no single best seed treatment for wheat or for coriander: fungicide seed treatments address susceptible fungal or water-mold diseases, and the formulation is chosen for the diagnosed problem and the crop named on its label.
For wheat, start from what the seed can carry. Fungicide seed treatments control seed-transmitted diseases caused by fungi, and soilborne fungi that cause damping off and root and crown rots. Seed lots from fields known to have low levels of loose smut, flag smut or common bunt come first, then wheat grown for seed in the following years, then lots with low germination caused by seedborne fungi. Loose smut is the case where the product type matters: the fungus lives inside the seed, so protective fungicides that only work on the surface of the plant do not control it, and when in doubt an appropriate systemic fungicide is the choice. Seed treatment does not control black chaff, which is a bacterial disease.
Keep your spray records in one place. Free to start.
Buy certified treated seed, or have the seed cleaned and treated at a commercial seed conditioner; if you treat on the farm, clean the seed first. If you must plant farmer-saved or bin-run seed, clean it thoroughly and treat it with a systemic fungicide before planting. Write the product, rate and seed lot in the spray and seed records.
For coriander (cilantro), against Alternaria leaf spot, a leaf disease, the first measures are Alternaria-free seed or hot-water treated seed at 127°F for 30 minutes. Any fungicide you add must name coriander or cilantro on its label.
Seed rot and damping-off: diagnose before treating
Seed rot destroys corn seed before germination. Damping-off kills seedlings soon after emergence. Water-soaked tissue can accompany Pythium infection. White-to-pink tissue occurs with Fusarium and bluish tissue with Penicillium. An infected seedling’s stem can become brown and soft near the soil line, with yellowing and wilting aboveground.
Check planting depth, soil temperature, drainage, compaction, seed quality and mechanical damage to the seed coat. Sweet corn, particularly supersweet hybrids, is more susceptible than dent corn.
Field disease risk and seedbed
Cool soils slow seedling growth, extending contact with pathogens. Continuous corn and high-residue conditions can increase disease pressure; account for rotation and seedbed conditions when choosing a treatment.
Heavy corn residue slows soil warming and can interfere with seedbed preparation. Chopping residue or using strip tillage in the planting zone can reduce contact between seed and surface residues. Where residue is removed for other uses, weigh erosion, soil-organic-matter loss and nutrient removal before deciding how much to harvest.
Seed treatments protect the early establishment period; continue the field’s disease-monitoring and residue-management program through the season.
Compare treatment expense with the expected yield response and grain price. If you replant after poor stand establishment, especially in wet spots, fungicide-treated seed may improve the survival of the replanted seed.
Treating seed on the farm and planting it
Seed-treatment formulations can be dry or liquid, concentrated or ready to use. Some products require commercial operators and closed application systems. For a product permitted on the farm, calibrate the treating equipment and use dedicated equipment where available. Overapplication can injure the seed; underapplication can reduce effectiveness.
Planter-box powders need uniform distribution over the seed. Uneven coverage leaves some seeds inadequately treated and changes the exposure received by others.
Check planter calibration, maintenance and the lubricant specified for the seed and equipment to reduce dust.
Treated corn and treated seed corn: labels, grain mix-ups and leftover seed in Minnesota
In Minnesota, treated seed labeling must indicate the treatment and name the substance applied. Nonpesticide processes such as inoculation or dye treatment need a brief description. An inoculant label must also show its expiry month and year.
When treatment is harmful to humans or vertebrate animals, the seed label must warn against food, feed or oil use. Seed treated with highly toxic substances requires the applicable poison symbol and statement.
The Minnesota Pollution Control Agency regulates waste treated-seed disposal. Follow its requirements for excess seed. Sellers in Minnesota must display the state’s treated-seed waste fact sheet conspicuously at the sales location.
Next step
For label reading see the label checklist.