With alfalfa breaking dormancy in parts of the country, producers should plan to keep a close watch for insect activity, says Jeff Whitworth, entomologist with Kansas State University Extension.
“Alfalfa weevils are probably the first insect pest to start scouting for at this time of year,” Whitworth says. “Some eggs were probably deposited last fall. With the warm weather we have had sporadically and which can be expected over the coming weeks, we have now accrued several degree days or thermal units towards hatching these eggs. Heat units accumulate for alfalfa weevils at temperatures above 48°F.”
Even so, Whitworth advises against being too quick to treat. “Wait until the field reaches the treatment threshold.”
Be on the lookout for pea aphids, too. “They can also start relatively early in the spring and can be a problem on first-year stands. If weevil treatments are applied, the insecticides will wipe out any beneficial insects that normally do a good job of keeping aphid populations under control.”
Reports of army cutworm activity last fall mean producers should also be scouting for that insect soon. “Army cutworms will start feeding again anytime temperatures are above 50°F,” Whitworth says.