Alfalfa weevil is one of the first pests to emerge in the spring. Purdue Extension entomologist Christian Krupke says even if temperatures are cool and it seems too early for pests to be a problem – that doesn’t mean it’s too early for the alfalfa weevil.
Krupke says growers should scout the newest growth and to look for “tip feeding”. “Early on it will appear as little pinholes in the leaves that aren’t opened up yet,” he says. “Later on, as the larvae grow, the grubs look like little caterpillars. As they grow – that feeding will become more noticeable and the leaves will become more tattered and it will be visible from farther away.”
He says if you can begin to see damage from the road – Krupke says you’ve missed the window to treat the field with an insecticide. “When the field takes on this silver appearance from the roadside and the field edge it indicates a lot of that new growth has been completely eaten down to the midrib,” he says. “At that point – most of the damage has been done.”
That’s why, Krupke says, it’s important to get in the fields early and see exactly how much damage, if any, has been done.
*Audio is courtesy of Purdue.*