Pests & Diseases

Pocket gophers are often the most damaging vertebrate pests in alfalfa. The amount and form of damage they cause can be quite varied but includes a loss in vigor and/or mortality of plants, damage to subsurface drip lines and loss of irrigation water down burrow systems.

The alfalfa weevil (Hypera postica) has developed resistance to the most common, effective and affordable insecticides used to control its damage (pyrethroids), complicating and threatening current management (Figure 1).

University researchers are testing methods for controlling herbicide-resistant weeds at harvest.

The drought conditions affecting some forage-producing areas of the country have seen an uptick in blister beetle activity. Blister beetles are rarely problematic in the Upper Midwest, but drought conditions increase the concern for blister beetle-infested alfalfa.

Will Ricks had a big problem with aphids in his alfalfa. “Aphids can do a lot of damage, especially in large numbers,” he says.

For dairy farmers, the goal for corn silage is simple: harvest the most tons possible of a highly digestible hybrid.