Originally Submitted: September 10, 2023
Written collaboratively by Adam Varenhorst, Philip Rozeboom, Patrick Wagner, and Brad McManus.
When we think of observing sunflower bud moths, it probably isn’t during the fall before harvest. In South Dakota, sunflower bud moths are considered a minor pest, with most of the damage to sunflowers caused when the caterpillars burrow into unopened sunflower heads. When this occurs, the sunflower heads become deformed. However, that isn’t the only location that the caterpillars will feed. There are two generations of sunflower bud moth in South Dakota, and the caterpillars of the later generation move to the base of the plant to overwinter. While scouting for Dectes stem borer larvae last week, I observed numerous sunflower bud moth caterpillars at the base of almost every plant (Figure 1). These caterpillars will overwinter in previously undisturbed pith and plug the entrance hole with frass or other plant debris. Unlike Dectes stem borer, more than one sunflower bud moth caterpillar can be observed in a single sunflower stalk. No management is recommended for sunflower bud moths.
Identification
Sunflower bud moth caterpillars have a smooth, cream-colored body with a dark head capsule. They can range in size from approximately one-quarter to one-half of an inch long at their final instar (Figure 2). Adult sunflower bud moths are gray in color, with two dark traverse markings across the back of the forewings. Their wingspan is approximately two-thirds of an inch (Figure 3).
