The combination of slow soybean harvest and rainfall in Northwest Ohio has made wheat planting challenging for some. What should you do with your wheat seed if you weren’t able to plant?
- Check with your seed dealer. Your seed dealer may have options available to return seed. Check with your seed dealer to see what your options are.
- Store seed in a climate and humidity-controlled environment. If you are unable to return seed or have bin-run seed, store the seed in a climate and humidity-controlled environment if possible. High temperature and high relative humidity increase the rate of seed deterioration, and the combination of the two is the most detrimental. In general, if the temperature in °F and the percent relative humidity added together are less than 100, then the environment should be OK to store the seed and maintain viability. Relative humidity can affect internal seed moisture content and keeping this lower is key to slow the rate of deterioration in wheat. Wheat stored at 77°F and 45% relative humidity for one year had a decrease in viability and vigor by 15-20% compared to storage at 40°F and 45% relative humidity.
- Protect seed from insect infestation. Wheat seed stored for a year or more is at risk of being infested by insect pests, especially Indian meal moth (IMM) and possibly grain weevils. This is one of the reasons for running a germination test before using wheat seed stored for more than a year. Protecting this seed from insect infestation can be difficult because of what it is typically stored in and relatively small quantities being store. However, there are products that can help protect the grain. Storcide II (chlorpyrifos-methyl + deltamethrin) is registered for use on small grains such as wheat. It is effective against a broad spectrum of stored grain pests, including grain weevils. Bacillus thuringiensis (Bt) (Biobit, Dipel) is registered for use on all grains including wheat but is only effective against IMM caterpillars. If the wheat seed is being stored in a grain wagon, the wagon could be covered with a tarp and a no-pest strip (DDVP, Dichlorvos) hung from a rib under the tarp. This insecticide is very effective against flying insects especially IMM adult moths. The wheels, frame and tongue of the wagon could be sprayed with a synthetic pyrethroid (e.g., Tempo) to protect the wheat seed from crawling insects.
- What about seed treated with fungicide? Fungi are among the major causes of seed deterioration in stored seed if conditions are favorable for their growth and spread. However, once seeds are adequately treated and stored under cool, dry condition, fungal growth will be greatly reduced. We routinely store fungicide-treated seeds (albeit small amounts) from year to year under cool, dry conditions without seeing a significant reduction in viability.
- What about seed treated with insecticide? Some wheat seed can also be treated with insecticidal seed treatments and are mostly the same type used for corn and soybean. These treatments will control Hessian fly, aphids, and other early season pests. The data is limited on how long these seed treatments last while in storage. Keep in mind, though, that the efficacy of the insecticides is short-lived in corn and soybean, lasting about 4 weeks. However, wheat planted past the Hessian Fly-Free date will likely not need a seed treatment anyway, since this date works well to prevent infestation of the main early-season insect pests of wheat.
- Test germination prior to planting in 2022. Seed quality is key to establishing a good crop, with a major component being physiological quality (seed germination and vigor). Over time, the physiological quality of a seed lot can change, especially because of its storage environment. Variability in temperature and humidity can cause reductions in germination as well as vigor (ability to emerge under less-than-ideal conditions). At minimum, any seed saved should have a standard warm germination test prior to planting in fall 2022. Based on the germination test, seeding rate may need to be adjusted. A seed vigor test can provide further insight into how a seed lot may perform in the field under stressful conditions compared to other seed lots. This information could help producers plan for what lots should be planted early vs later, as well as positioning fields that are typically more stressful for seedlings. A higher vigor score is usually more tolerant of adverse conditions than a lot with a lower vigor score. Common seedling vigor tests for small grains would be an accelerated aging test or a tetrazolium (TZ) test.
Strelec, I., Popovic, R., Ivanisic, I., Jurkovic, V., Jurcovic, Z., Ugarcic-Hardi, Z., and Sabo, M. 2010. Influence of temperature and relative humidity on grain moisture, germination and vigor of three wheat cultivars during one year storage. Poljoprivreda 16:20-24.