Pictorial guide for common insect pests of alfalfa in South Dakota
Content by Adam Varenhorst
Large grasshopper populations have been observed in Central South Dakota. These populations have required management in other crops and should be monitored prior to and during winter wheat planting.
Another insect that has been mistaken for the Asian giant hornet (also known by its media-popularized name of ‘murder hornet’) is the horntail wasp. Horntail wasps are wood-boring insects that are harmless to humans, as they do not have venom and cannot sting.
An additional soybean defoliator to monitor this week is the redheaded flea beetle. Although these beetles are typically not a serious soybean pest, large populations can result in considerable defoliation.
We have received reports of bean leaf beetles feeding on soybean in a couple different areas of the state. Bean leaf beetles go through two generations each year in South Dakota. Adult bean leaf beetles can vary in color from brown, yellow and orange to red.
Every year, there is a risk that sunflower in South Dakota will be infested by Dectes stem borer larvae. At this point in the season, adults are active, and females have likely been laying eggs in sunflower plants.
Squash bugs are a headache for gardeners almost every year in South Dakota. As their name implies, squash bugs feed on squash along with many other cucurbits. Injury caused by extensive feeding appears as wilting and may result in the death of infested plants.
Potato leafhoppers are a migratory pest that commonly impact alfalfa fields throughout South Dakota. Feeding injury caused by potato leafhoppers resembles drought stress and, if left untreated, can reduce both yield and forage quality.
Banded sunflower moths are active in South Dakota, which means it is time to start scouting sunflowers for their eggs. Banded sunflower moth caterpillars can reduce yields and oil content by feeding on the developing florets and tunneling into developing seeds.