By Mike Surbrugg

msurbrugg@joplinglobe.com

LAMAR, Mo. — As temperatures begin to climb, it opens the door for the alfalfa weevil, said Jay Chism, University of Missouri Extension agronomist in Lamar.

“Adult weevils deposit eggs on new alfalfa growth when temperatures are above 50 degrees for several consecutive days,” Chism said.

Larvae normally hatch in April, May and June and begin to eat the growing tips of alfalfa plants.

The first visible sign of damage is small holes in the leaflets. Damage continues to increase as larvae get stronger.

Chism recommends checking for weevils by collecting 50 alfalfa stems and tapping them into a white bucket. Collecting 10 stems from five different locations provides a random sample of what is happening in the field, he said.

Insecticide control is justified when one or more larvae is found per stem early in the season, he said.

Spring is also critical for grazing management to reduce summer grazing problems, said Eldon Cole, extension livestock specialist, Mount Vernon.

Allowing cattle to selectively graze means some fescue will be closely grazed and plants in other areas get time for growth.

Mike Surburgg is The Joplin Globe’s farm editor.