Early planted sunflowers in the north are starting to bloom meanwhile sunflower plants to the south are in R1. With bloom time also comes the potential for seed feeding insects and knowing how to protect your crop. The banded sunflower moth is one of these insects of concern. The moth itself doesn’t do damage to the plant, but rather its larvae. When the larvae hatch they eat the seed and then exit, leaving behind a small hole. Typically the moth will move into the sunflower field around the R3 stage and will lay their eggs on the back of the bracts.
Scouting can be done one of two ways. The first is by looking for eggs on the back of the bracts when the sunflowers are R3 to R4. The threshold for the number of eggs per bract varies based on the cost of treatment and market price. Right now an $18 sunflower crop with an $8 treatment with 20,000 plants per acre would need 3.2 eggs per 6 bracts to reach threshold. The second is to monitor for the adults by walking into the field away from the margins and looking for the moths. They tend to rest on the leaves during the day and can often be seen when you walk through a field. An $18 sunflower crop at 20,000 plants per acre has a threshold of less than one moth per 100 plants. To help monitor the adults there are traps available that get placed within a field. If you would like some traps to set out Nuseed will gladly provide you with some.
NDSU has some great resources out there with videos for egg scouting and tables showing Economic Injury Levels so a grower knows when they should spray. Click on link below to seed video.
When putting together a monitoring trap remember to wear gloves when placing the pheromone so the human scent doesn’t get on it. Also, use a fiberglass pole or a piece of wood to attach it to in the field away from the margins.
Optimal time to spray with an insecticide is at R5.1 (early bloom) and most labeled insecticides are very effective. If you have a confection field, consider spraying twice.