Wayne Bailey spends much of his summers in fields searching for pests. The University of Missouri Extension entomologist says it is something farmers can do as well.
In a recent video, Bailey demonstrates techniques for scouting insects in an alfalfa field. He gives farmers a practical approach to looking for pests that are robbing yield and ultimately, a farm's bottom line.
The alfalfa weevil hit the crop hard this spring, eating its way through the leaves of alfalfa with potential to ruin its forage value.
"Alfalfa weevil defoliates the plant, and if populations are high enough they can take all the leaf material off the plant, leaving only the stems," Bailey says. "We end up with a field that's what we call 'silvered,' where all the leaf material is gone and we just have remnants of leaf veins that turn silverish brown."
That is a big problem for farmers. Since most of the protein is in the leaves, the leftover stems do not provide much feed value for a herd.
Pea aphids are adding to that damage. The green insects, which are the size of a pinhead, puncture alfalfa with piercing/sucking mouthparts to drink its juice.
"With high populations of pea aphid we see a yellowing of the field and a loss of quality to the alfalfa," Bailey said. "They are more of a spring problem, and while they won't kill this 2-year old stand, they can cause a new stand to die."
In this video, he discusses how a 5-gallong bucket and sharp pocketknife will help farmers determine if an alfalfa field has surpassed a pest threshold level.