How to Clip Sunflower Heads for Weevil Prevention

Plant several rows of early blooming sunflowers around the outside of your sunflower field one week to 10 days earlier than you plan to plant your main crop of sunflowers.

Decide what the level of infestation is that your crop can sustain before you lose money on the crop. To do that you need to know the cost of spraying the exterior of your field with insecticide and the predicted selling price of your sunflowers. Contact the agricultural extension agent of your local university to help you estimate the number of weevils per sunflower head your field can handle from year to year.

Monitor the field crop of sunflowers for signs of adult weevils by taking samples from all sides of your field. You will collect three flowerheads per side.

Walk 75 feet into your field and randomly select three plants. Don't evaluate the plants before selecting them.

Place a plastic bag over the seedhead and hold the bag with your free hand.

Clip the head off the sunflower by placing the sickle below the bulge at the bottom of flowerhead with the blade facing away from you. Cut through the stem with the sickle and collect the flowerhead. Mark the field side and sample number on the bag.

In the barn, lab or other work area, remove the flowerhead from the bag and place it on the table. Check the bag for weevils and count them.

Spray the face of the flowerhead with DEET. The DEET will make the adult weevils come out of the head. Count the weevils and enter the numbers into a logbook. Compare to your threshold number determined earlier.