We know there are many benefits that make no-till worthwhile — less cost for fuel and labor, improved soil structure and health, better water infiltration and holding capacity — the list goes on.
Unfortunately, every farming system has its challenges, including no-till. Recent reports out of Indiana and Illinois say no-tillers may be dealing with some pests this season.
Scout for Armyworms
University of Illinois Extension says there was significant armyworm damage to a field of no-till corn that previously had a cereal rye cover crop in McHenry County, located just northwest of Chicago.
Crop scientist Michael Gray says that throughout his career, the most common reports of damaging infestations occurred in corn where rye was a cover crop. That’s because cool, wet springs favor development for the pest, and hinder parasite and predator populations.
Larvae primarily feed at night and often go unnoticed until injury is severe, so scouting is important. For corn, University of Illinois Extension recommends examining 20 plants in five locations of one field, for a total of 100 plants, to determine the percent of damaged plants.
Extension says an insecticide treatment may be justified when 25% of seedling corn is damaged. If corn is past pollen shed, then insecticide may be necessary when feeding occurs above ear level.
The good news is that in most years, armyworm populations are below economically damaging levels thanks to predators, parasites and pathogens. DuPont Pioneer recommends no-tillers terminate cover crops early, and use effective at-planting residue management to reduce risk of pest damage.
Beat Back Slugs
Purdue University Extension says reports of slug damage are coming out of north-central Indiana due to a cool, wet spring.
The buildup of slug populations is greatest in no-till systems and weedy fields, since wet soils and lots of residue are optimum conditions for slug survival. As juvenile slugs grow, so will their appetites.
Slugs aren’t insects, so conventional methods of insect control, including seed treatments and insecticides, will not work. One option is a metaldehyde-pelleted bait, but spreading these pellets evenly can be a challenge, Extension says. Experts recommend using the bait as a last resort to protect crop stands in high-populated slug areas.
Fortunately, feeding will slow down as sunshine and temperatures increase, which will help the crop grow faster and get out of the danger period. Most damage and stand losses from slugs occur when fields are too wet to plant and seed slots didn’t close properly. Virginia Tech Extension says that any practice that allows for more vigorous plant growth, such as use of row cleaners or waiting until soils have warmed to plant, will help.
For more information, check out the article “6 Tips to Help No-Tillers Eradicate Yield Robbing Slugs” from the April 2015 issue.