SCN populations thrive despite very cold winter
The record low temperatures over the past few months may reduce some pest populations this spring, but university and Syngenta experts predict soybean cyst nematodes (SCN) will still threaten yields.
“Many growers hope the cold weather we’ve been experiencing will help decrease pest populations,” said Dale Ireland, Ph.D., seed treatment technical product lead at Syngenta. “But it doesn’t affect SCN.”
According to the Iowa State University Extension, unusually large numbers of SCN may infest fields where soybeans were grown in 2012—a year when SCN reproduction was particularly high. The number of SCN eggs in the soil at the time of planting contributes significantly to the degree of damage and yield loss to SCN. With an overwintering survival rate of nearly 100 percent, the potential for damage in 2014 is great.
The University of Nebraska – Lincoln suggests SCN can reduce yield by 20 percent to 30 percent, even when plants appear to be green, healthy and have no visible symptoms. Soil testing is the best way to determine if SCN is present. Since 2005, SCN has been identified in 29 Nebraska counties for the first time as a result of soil testing.
To help manage and reduce SCN populations in SCN-infested fields, researchers at the Iowa State University Extension suggest rotating crops, selecting SCN-resistant varieties and using appropriate seed treatments.
“Choosing a variety with high-yield potential and good nematode tolerance along with a nematicide seed treatment is vital to managing SCN,” Ireland said.
Syngenta offers Clariva Complete Beans nematicide/insecticide/fungicide, an on-seed application of separately registered products. It adds a nematicide to the company’s broad-spectrum insecticide/fungicide seed treatment to add effective protection against SCN throughout the season, on top of broad-spectrum defense against early-season insects and diseases.
“Clariva Complete Beans offers season-long protection against SCN by reducing nematode activity and damage with Pasteuria nishizawae (P. nishizawae), the nematicide active ingredient,” Ireland said. “The treated seed is covered with millions of P. nishizawae spores that colonize and attach to the nematode, ultimately killing it.”
Click the animation here, “The stages of Pasteuria nishizawae,” shows how the nematicide protects soybeans from SCN. This process occurs in five stages, with the P. nishizawae spores remaining in the soil and repeating the cycle, leading to a drastic decline in pressure so farmers can grow more soybeans, Syngenta notes.