Know What Your Seed Treatment Won't Do!

Just knowing corn seed is treated isn't enough.

Published on: Apr 12, 2011

Here's a real conversation which took place recently.

Neighbor: "So what are you using on your refuge corn for insect control?"

Farmer: "It' got seed treatment on it."

Neighbor: "So what kind is it?"

Farmer: "I'm not sure, Poncho maybe. The seed company took care of it."

Neighbor: "So what rate of whichever product you have is on the seed?"

Farmer (Growing impatient): "All I know is it's treated with a seed-coated insecticide and I shouldn't have to worry about it."

The farmer in this example is sharp. He simply trusts his seedsman to make those decisions. And hopefully, his seedsman is making the right call for his area. But let's take a closer look at why you might want to ask more questions to pin down exactly what type and how much seed treatment active ingredient you are getting when your seed goes in the ground.

First, there are several reputable seed treatments on the market that are classified as insecticides. Two examples are Poncho and Cruiser. One big unknown to turn into a known is whether or not the seed treatment provides rootworm protection against corn rootworm larvae.

Second, what level of product is on the seed? Many of these products today come at three levels- low, medium and high rate. For example, Poncho is now available at the 150, 500 and 1250 rate. Most entomologists suggest it takes the 1250 root to work against rootworms, and add that even then, it's not as effective as the traditional soil-applied insecticides.

Third, what's the likelihood of having a sever pest problem in your area? For example, if you live in northwestern and north central Indiana, moving eastward, the western corn rootworm variant that lays eggs in soybeans is more prevalent. However, it's also been identified in spots in central and southern counties.

If you have high rootworm pressure from the variant, and you're planting corn into soybeans, you're going to want the 1250 (highest) rate. Even then, most university studies across the Midwest indicate that under high pressure, control of seed-applied insecticides is better than the check (doing nothing) but not as good as soil-applied insecticides.

If you live in central or southern counties and know you don't have much pressure from the variant, and you're staying with a corn and soybean rotation, it's possible you won't see damage using only a seed treatment at the highest rate. You may not even se damage with seed treatment at the medium rate, depending upon pressure from the rootworm population.

Here's the point. Knowing your refuge corn is treated with an insecticide isn't enough. You also need to know what level it's at, and how that compares to rootworm pressure in your area.