Renewable Farming

Your littlest livestock: Best protection against plant pests and disease

The best news of our day so far is this fact from longtime friend Hal Brown, Mulberry, Indiana: “Did you know there are 1,700 beneficial insects for every one specie of bad insect?”

No… I didn’t know that, even though I grew up on a southwest Iowa farm, spent almost 10 years at Farm Journal and have lived on a farm here in northwest Iowa almost 40 years. 

Cover crop on Hal Brown’s farm following wheat

Hal provides habitat for the beneficial critters, and they come. “Cover crops are our third crop, every year,” he says. He blends several species of cover crops, which is consistent with what microbiologist Dr. Robert Kremer says: Each species of plant favors an array of microbes and larger “food web” creatures in the soil and in the crop canopy.

Hal mixes several species into his cover crop seedings. Since tillage radish does not encourage mycorrhizal growth, he includes grasses and legumes which do. The result is an array of complimentary broadleaves and grasses which attract pollinators and lots of beneficial microbes into the soil food web.

Hal raises about 250 acres of wheat for seed wheat each season. This acreage offers a rotating area for installation of tile or waterways, and provides diversity in cover crops early in the season.  One of his comments indicates the importance of cover crops in his rotation: “We see covers as the third crop in our rotation every season.”

Hal adds: “We are basically no-till and let the covers be our tillage.  Living roots can do far more than steel — with many other benefits once 
you know what different species can do.  At least that is from my viewpoint here in Indiana.” 

Today, he e-mailed us to say:  “Our ditcher is finishing up a project in the wheat covers.  He says it is like working in a jungle.  There are huge black spiders and bees everywhere, he says.”

Advanced corn bacterial leaf stripe

Beneficial insects are predators against the bad bugs. And beneficial bacteria plus fungi are predators against evil organisms down there, such as the “new” bacterial corn disease just reported in Illinois: “Bacterial Stripe.”  The link nearby takes you to the University of Illinois IPM bulletin. The  photo of bacterial stripe on corn is courtesy of the University of Illinois Plant Clinic.

In late September, the Illinois Department of Agriculture also confirmed a new fungal leaf disease, “Tar spot.” 

I did know, more than 20 years ago, that persistent infusion of glyphosate into the soil kills beneficial bacteria, and shifts the soil microbial population toward the fungal side. Until the glyphosate era, “Corn was one of the healthiest crops out here,” as Dr. Don Huber says.  Now it routinely needs fungicides in a corn-soybean rotation without benefit of cover crops. 

Practical Farmers of Iowa has been emphasizing cover crops for several years, and a direct result is that thousands of acres across the state are protected through more months of the growing season. This should help reduce waterway nitrates, as the covers lock up nitrates against leaching and release them as they decompose during the growing season.

Jill Clapperton

Practical Farmers of Iowa hosted Jill Clapperton, co-founder of Rhizoterra Inc., as featured speaker at the 2015 PFI Conference. Her presentation was rich with usable details.  We encourage you to visit their site for more details on cover crops.

Our neighbor, Dennis Kruger of Kruger Seed at Dike, IA, has been seeding cereal rye as a cover crop this season and last season. This fall, he flew the cereal rye into standing beans. Following the soybeans, he vertical-tilled the bean stubble with a tillage tool similar to Jim Martindale’s CurseBuster.

The field looks like smooth, green velvet. It’s evidence that the large-scale operators can do an excellent job with cover crops, which require intensive management — especially at seeding time, when a lot of pressure is on fieldwork.

Overview of cereal rye in mid-October

 Here’s a closeup of the cereal rye:


Cereal rye as of Oct. 14

Published Oct. 7, 2015 by Jerry Carlson

Updated Oct. 14, 2015