By Janet J. Knodel
Extension Entomologist
The IPM Survey scouts captured the first banded sunflower moths in pheromone traps located in Richland, Ramsey and Cavalier Counties of North Dakota last week. It is still very early for sunflowers, V2 to V8 crop stages. Adult moths spend most of their time in vegetation near sunflower fields during the day. When the sunflower is in the preferred crop stage, midsized buds (R3), eggs are deposited on the outer whorl of bracts. Very few eggs are laid on plants at pollen shed (R5.1) and later.
Most eggs are laid singly or in small clusters. Eggs hatch into larvae about five to eight days after being deposited. Egg laying will continue through early August. Egg scouting is a good way to determine if your field is at economic threshold level. This provides more time to arrange for aerial insecticidal spraying if necessary. See the NDSU Extension YouTube video on Banded Sunflower Moth Egg Scouting. The current threshold (economic injury level) for banded sunflower moth eggs is based on insecticide treatment costs, plant populations and sunflower market prices (see Table below with the current oilseed sunflower price). The excel spreadsheet that calculates the threshold is available on the NDSU Extension Entomology website.
The first migratory sunflower moth also was detected in the pheromone trap located in Richland County, only one moth per trap per week. When sunflowers start to flower, scouting will be a necessity. The economic threshold for sunflower moth is one to two adults per five plants at the onset of bloom (R5.1) or within seven days of the adult moth’s first appearance. There is an economic threshold based on pheromone traps and it is set at 28 moths per trap per week (or 4 moths per trap per day). Sunflower moths are small light-colored moths that hold their wings over the abdomen and appear cigar-shaped. Adults are about 8 to 12 mm long. The early blooming fields will be targeted by sunflower moth.