Soybean farmers around the state faced one of their biggest enemies this year.
After early indications suggested this would be a low soybean aphid year, farmers around Minnesota were faced with one of the worst years for the insects in recent memory.
Bruce Potter, assistant professor of the department of entomology with the University of Minnesota, said the soybean aphid problem started out as a wide spread problem and wasn't confined to one area.
"It started out fairly slow, but the main difference is instead of areas of the state having problems and it spreading out from there, the entire state of Minnesota developed problems simultaneously," said Potter.
Gene Stoel, a board member of the Minnesota Soybean Growers Association and producer in the Lake Wilson area, said soybean aphids bounced back quickly this year.
"Aphids came back this year more than they have in any past year," said Stoel. "It was mainly due to the climatic conditions we had this year."
Potter said farmers around the state took action around the same time, spraying for soybean aphids early in the growing season.
"Southwest Minnesota started spraying the same time that northwest Minnesota and southeast Minnesota," said Potter.
Stoel said some companies were promoting early spraying - a practice that proved unsuccessful for many farmers.
"We're finding out that really doesn't do any good," said Stoel.
Potter said fields that were sprayed too early and didn't receive a second treatment later in the season likely saw a loss.
"There were growers that wanted to get it all over with early and just mixed their insecticide with their glyphosate application," said Potter. "The vast majority of those, if not all, needed to be treated. It was just too early."
Potter said it can be difficult to time spraying for soybean aphids.
"If you're spraying when the soybeans are growing, the top of the plants have no insecticides," said Potter. "In effect, no matter what the chemistry is telling you, the residuals are short-lived."
Stoel said it's important to spray for soybean aphids when a threshold is met.
"The threshold for spraying aphids is 250 aphids per plant. Once it reaches that threshold, it's time to spray. That gives you a window of three to four days to spray.
"If conditions are right, that population can quadruple after four or five days. You would be suffering some loss at that point."
Potter said it's difficult to predict how widespread or where soybean aphids will hit, but based on studies done last fall, this year was thought to be a down year for soybean aphids.
"Throughout the upper midwest, we have suction traps looking at aphid movements in the fall," said Potter. "Those numbers were fairly low. Everything suggested that populations going into the winter were a lower then they had been in previous years."
Potter said soybean aphids can travel great distances, including to areas that might otherwise not have a soybean aphid problem.
"Even if we would have no over-wintering in Marshall, all the buckthorn was free of aphids," said Potter. "If there was a problem in Mankato, for example, and you produced a lot of winged aphids with the right wind conditions - Marshall could still end up with them."
Stoel said the University of Minnesota a is working with the Minnesota Soybean Growers Association on a survey of soybean yields for Minnesota.
To participate in the study, visit www.mnsoybean.org.