The first trap catches for banded sunflower moth (BSM) and Arthur sunflower moth (ASM) occurred this past week. Sunflowers are growing fast. At the trapping field sites, the crop stages ranged from V5 to R1 (terminal bud at top of plant forms a miniature floral head).

Trap catches for BSM were low and observed at only 2 trap sites in Cass (16 moths) and Hettinger (1 moth) counties (see map; Source:  NDSU IPM Crop Survey insect trapping network). Only one ASM was captured only at the Golden Valley trap site. For sunflower moth, one moth per trap was captured at trap sites in Foster and Renville Counties this past week.

Scouting for BSM and ASM:  BSM is a small (¼ inch long), straw yellow moth with a triangular, dark brown band crossing through the middle of the forewing (Figure 1). ASM is similar to BSM in size but, it is a whitish-gray moth with a broken brown and gray band on the forewings.

When sampling, use the W pattern and begin counting at least 75 to 100 feet into the field to avoid field margin effects. Count moths on 20 plants at 5 sampling sites to obtain the total number of moths per 100 plants. When scouting during the day (late morning to early afternoon), the moths remain quiet, resting on upper or lower leaves of sunflower plants or other neighboring broadleaf plants like soybeans. Look for the moth fluttering from plant to plant when disturbed. Yellow square has the 2020 Economic Threshold for BSM and ASM combined.Please see the revised Banded Sunflower Moth E823 (2019) Extension publication for more information.

Janet J. Knodel

Extension Entomologist