Alfalfa Weevil
Information for this article was compiled by Dr. Kevin Wanner (MSU Extension Entomologist) and Dr. Emily Glunk (MSU Extension Forage Specialist).
Alfalfa weevil is the key insect pest of alfalfa, causing variable levels of economic damage across Montana each growing season. The female weevils lay eggs in alfalfa stems Larvae hatch and crawl up to the developing terminal buds where they chew small “pin” holes in the leaves. The larvae develop through four instar stages. The larger 3rd and 4th instar larvae feed openly on unfurled leaves and cause the largest economic loss. Severe...