Impacts of treated seed

Each spring I plant several food plots to benefit wildlife. I usually plant a combination of corn, soybeans, and occasionally sunflowers. Sometimes I broadcast the seed and incorporate by lightly disking, especially the soybeans. By doing this, there is always some seed left exposed on the surface. All seed today has various chemical treatments. I’m concerned about the toxicity to wildlife if consumed, especially by wild turkeys. Is this a valid concern? 

Michael Mahn, Auburn, Iowa 

Seed treated with insecticides called neonictinoids came into widespread use in the mid-1990s in the U.S. and Canada. The treatment provides protection from insects, not only to the seed but in the plant as well. Treated seeds and the resulting plants are far less susceptible to insect damage, so these treatments have helped to increase yields in grain crops, fruit and vegetables. Treated seed has made farming operations more efficient and helped to produce more food and keep prices down.

In the last decade, concerns have been raised, and a number of studies have been conducted to try to evaluate the impact of treated seed on birds when the seed is eaten. In addition, some researchers believe that insects feeding on the plants produced with treated seed ingest small doses of the insecticide, and birds feeding on those insects might be affected. Other researchers are studying the potential impact of the treated plants on bees and other pollinators. Neonictinoids have a long half-life. In other words, the product can remain in soil and plants for a number of years.

There is good reason to study the issue, but the jury is still out on the potential impacts. Studies done in Europe and the U.S. looking at treated seed consumption by gray partridge and red-legged partridge (in Europe), and sharp-tailed grouse and prairie chickens (in the U.S.) suggest that most of the seed consumption takes place in the fall when cover crops are planted rather than in the spring. The birds did not consume lethal doses of the seed, but scientists want to know whether consuming the seed could ultimately affect survival or reproduction. No conclusive studies have shown ill effects on grouse, partridges, pheasants or wild turkeys so far, but there remains much to learn about the long-term effects of these pesticides. Being careful to prevent spills when planting or carrying treated seed is advisable.

Untreated seed, where available, is an option for hunters developing food plots. Because most seed is treated, there are some things you can do to avoid potential problems. Make sure you clean up or cover any spills of seed when you are planting. When you lightly disk, drag or culti-pack your plots, make sure most of the seed is covered. That will limit access to the treated seed by foraging wild turkeys and other birds. It is not likely that your food plots planted with treated seed pose threats to the local wild turkey population, but keep your ear to the ground for more information as additional studies are done. Hopefully, further study will help us determine what methods of keeping insects at bay are safest for all concerned.    


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