Scouting Method: Like most insects, field borders generally will have higher weevil numbers so it is important to move deeper into the field. Scouting should begin in the R-3 and R-4 (bud) stages and continue to R-5.7. At the bud stage the weevils tend to feed and hide among the bracts. An easy way to get them to emerge is spray a mosquito repellent containing Deet on the face of the heads. The same can be used when the buds have opened. NDSU has created a video in which Dr. Jan Knodel, NDSU Entomologist, walks you through the process of scouting for the weevil and determining potential crop loss. Watch it here: Scouting for Red Sunflower Seed Weevil in Sunflowers .
Management: There are many effective insecticides labeled for the adult weevils. Since the red seed weevil adults need to consume pollen before laying eggs, spraying at early pollen shed when about 30% of the plants are at R-5.1 is recommended. It is recommended that confections be sprayed even earlier and two sprays may be warranted depending on populations. The timing of control of the red seed weevil is well suited for controlling both the banded and the sunflower moth. For the gray weevil spraying at early bud stage R-2 is recommended. However, gray weevil populations have historically been low and no control has been required.
Common Mistakes: Waiting too long to scout and take control measures are historically the most common mistake with the red seed weevil.
Research: The goal of research programs partially funded by the NSA is to develop hybrids that are resistant to the seed weevil complex. USDA ARS Sunflower Unit in conjunction with NDSU and SDSU have been field screening currently available sunflower accessions, interspecific crosses, and lines for those having reduced seed damage from larval feeding by the red sunflower seed weevil. The discovery of germplasm that has lower insect damage can provide the seed companies with breeding material to be incorporated into hybrids targeted to locations where specific insect problems occur. A long-term goal is to identify germplasm with resistance or tolerance to more than one insect pest. The NSA has provided a post-doctoral scientist to the USDA ARS Sunflower Unit for 2008-11 to accelerate this work.
Crop Surveys: The Sunflower Crop Survey is conducted bi-annually prior to harvest. Volunteers from all levels of the sunflower industry visit sunflower fields to survey the crop condition. Teams survey for yield and production practices, weeds, insects, diseases and bird damage.
Another resource about Insects can be found in the Archive section of The Sunflower magazine.