It’s not a question as to whether John Lindamood plants treated corn and soybean seed. That’s a given. It just gets down to which fungicide and insecticide products are most cost effective to his northwest Tennessee operation.

Lindamood and his father Bill don’t chance seedling exposure to cold, damp soil early on; symptoms that can create powerful problems that are difficult to overcome.

They farm a corn, soybean and cotton rotation near Tiptonville, TN, and operate a regional cotton gin. Every seed they plant is treated for disease and insect protection. Backup plans are sometimes needed, but not enough to turn the Lindamoods away from a total treatment program.

“We have made the decision to commit to fungicides and insecticide treatments on seed,” Lindamood says. “That’s a bottom line that works for us.”

He can’t be sure how much yields are increased. “But I know from observing the heath and vigor of the seedlings that we’re getting a better stand establishment on our corn, beans and cotton,” he says.

Seed treatments can be confusing to growers because it’s difficult to know exactly how much the treatments cost and there are several options to consider, says Scott Stewart, University of Tennessee Extension entomologist.

 “For corn, unless you special order your seed differently, almost all corn seed will come standard with a base fungicide and insecticide seed treatment,” Stewart says. “Soybeans, however, can be purchased untreated or with various selections of fungicide and insecticide treatments.”

Farmers can expect an increase in corn yields with treated seed, Stewart says. “It’s still unpredictable how much of a yield growers will obtain with treated seed,” he says. “But the 4-5-bu. range is still common among many growers.

“For soybeans, they can look for an average of a 2-3-bu./acre yield increase with insecticide treatments,” Stewart says. “The yield response varies depending on pest pressure. In some years there may not a response, but I’ve also seen 5-10-bu. yield increases in test plots.

 “Since growers can hardly find seed without an insecticide seed treatment, I guess it’s a good thing that these treatments are generally recommended in most of the South,” Stewart says. “Poncho 250, a clothianidin from Bayer CropScience, and Cruiser 250, a thiamethoxam from Syngenta, are the standard treatments marketed by seed companies, but higher rates are available upon request.

“Both are pretty good broad-spectrum choices, but neither is foolproof; neither provides substantial protection against cutworms. Cruiser 250, or the 500 rate available by request, won’t provide much protection from sugarcane beetles,” he says.

Stewart says that when growers order the 500 rate of Poncho or Cruiser, a nematicide is often included. Some feel the nematicide isn’t as valued in some areas as it is in others. “The value of a nematicide seed treatment for corn appears to be limited in Tennessee,” Stewart says.

He notes that the cost of corn seed treatments is sometimes difficult to determine, but it typically ranges from $15 to $30/bag of seed. “It isn’t transparent so you have to compare seed costs with and without various treatment options,” Stewart says.

Stewart says Acceleron seed-treatment packages are marketed by Monsanto for seed under DeKalb, Asgrow and Delta Pine, but treatment components vary across crops. “In corn, the standard Acceleron treatment currently includes a base fungicide and insecticide seed treatment (Poncho 250),” he says.

Lindamood says he depends on various treatment packages offered for Pioneer and DeKalb corn hybrids. “Our seed providers keep us informed on which treatments are recommended for our area and we decide which ones are the most cost effective,” he says.

Hybrids are stacked with glyphosate and Bt genes. “Since cutworms aren’t fully controlled by the treatment, we also spray our fields with a pyrethroid,” he says. “We also keep fields clean after harvest with Valor herbicide to reduce host weeds for insects.”

Unlike much corn seed, soybean seed can be purchased untreated, with a base fungicide seed treatment, with fungicide plus insecticide, or with fungicide, insecticide and a nematicide. Costs can vary from $10 to $14/bag.

“Downstream treatments can typically be made by your local seed distributor,” Stewart says. “Fungicide or fungicide plus insecticide seed treatments are often recommended in the South, especially in early planted soybeans. The standard base fungicide treatments offered by seed companies are pretty robust.”

He says the most common insecticide treatments are imidacloprid (Gaucho) or thiamethoxam (Cruiser).

“Another insecticide option is NipsIt (clothianidin) being packaged with fungicides as Inovate from Valent. We have less data on this product but it appears comparable to the other options.”

Stewart says that unless there are significant infestations of nematodes, nematicides should not have much value to growers – “so sample your fields for nematodes.” 

He says growers can order soybean seed from Monsanto and other lines with Acceleron or Acceleron I. “Acceleron just includes fungicide components, while Acceleron I includes fungicide and insecticide (imidacloprid),” he says.

Lindamood usually depends on a Gaucho or Cruiser treatment for beans. “There’s absolutely no question in my mind that there’s no more important part of the growing season than the day you put seed in the ground,” he says. “Seed treatments give us more confidence in getting that seed started.”

Do late-planted beans benefit? “Not as much, Stewart says. “Normally in soybeans, if there’s a delay in planting, as was seen for many growers in 2011, you’re not going to see as much benefit from seed treatment as with early planting,” he says.

“We encourage growers to use seed treatments on early planted beans for sure, then maybe back off especially if they are planting later. There will be less chance for cold-season diseases. Beans grow up more quickly and get through susceptible stage.”