Start Scouting For Alfalfa Weevil Now Says Specialist

SPRINGFIELD, MO.
   As the spring begins to warm, forage producers need to be on the lookout for alfalfa weevil, according to Jay Chism, agronomy specialist with University of Missouri Extension.
   This is especially true now because the alfalfa weevil benefits from mild weather in winter and spring seasons.
   “Adult weevils will deposit eggs on new growth anytime the temperatures rise above 50 degrees for several consecutive days,” said Chism.
   Normally, alfalfa weevil larvae hatch in April, May and June. The larvae then embed themselves into the growing tips of alfalfa stems removing leaf tissue as they feed.
   The first damage a farmer who is scouting his field may notice will be small feeding holes in the leaflets that grow out of the terminals of plant stems. As the larvae begin to grow larger more plant tissue is consumed and this may cause economic loss.
   “The best way to scout for alfalfa weevil is to collect 50 alfalfa stems and tap them into a white bucket,” said Chism.
   Collecting 10 stems at five different locations will provide a good random sample of the field. The economic threshold for alfalfa weevil larvae is one or more per stem.
   “When a farmer finds one or more per stem early in the season, an insecticide application is the main management option,” said Chism.
   If, after scouting, a farmer determines that an insecticide application is necessary, contact the nearest University of Missouri Extension office for alfalfa weevil larvae iinsecticide recommendations . Agronomy specialist Jay Chism can be reached at (417) 682-3579 and agronomy specialist Tim Schnakenberg can be reached at (417) 357-6812. Δ