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Sunflower Insect Trapping (07/25/19)

Sunflowers were late planted this year and most fields now range from R1 (terminal bud with a miniature floral head) to R3 (immature bud elogates > 2 cm above the nearest leaf).

Sunflowers were late planted this year and most fields now range from R1 (terminal bud with a miniature floral head) to R3 (immature bud elogates > 2 cm above the nearest leaf). 

Banded sunflower moth (BSM) and Arthuri sunflower moth (ASM)

Identification:  

The banded sunflower moth, Cochylis hospes Walsingham, is a small (¼ inch long), straw yellow moth with a wingspan of about ½ inch. Its forewings have a triangular, dark brown band crossing through the middle of the wing (Figure 1). The peak of the triangle is oriented toward the leading margin of the wing. The hind wing is grayish black.

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Arthuri sunflower moth, Cochylis arthuri Dang, is similar to BSM, small (¼ inch long), whitish-gray moth with a wingspan of about ½ inch. Its forewings are crossed by a broken brown and gray band and the outer ¼ has brownish markings and dark fringe (Figure 2). The hind wing is white to gray

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Trap counts for BSM and ASM from the NDSU IPM Survey insect trapping network indicate that BSM increased this past week in NW, NE and SE areas of ND. ASM is fewer than BSM. Scouting is key now for both moths and should be conducted from the late bud stage (R3) through early flowering. If treatment is warranted, it should be delayed and applied at the R5.1 sunflower plant growth stage (when 10% of head area has disk flowers that are flowering). At R5.1, most BSM or ASM eggs have hatched and young larvae are feeding on the florets on the face of the sunflower head.

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Scouting for BSM and ASM:  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. The table to the right shows a similar threshold for BSM and ASM as last year.

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Sunflower moth:

Sunflower moth migrates to North Dakota from the southern states. Because of the migratory nature, it is usually not a major problem for sunflower production in North Dakota. However, late-planted sunflower fields will be at more risk for sunflower moth infestation since flowering will be later.

Identification:  The adult moth is about ⅜ inch long, grayish-tan and has a cigar-shaped appearance when at rest.

Trap catches for the sunflower moths were observed at most trap sites, except NE and SW sites (see map on next page; Source:  NDSU IPM Survey insect trapping network). Most traps catches were <10 moths per trap per week, so the infestation is considered non-economic, so far.

Scouting:  Moths move into fields during early bloom. It deposits its eggs on the face of the flower. Damage is caused by the larval feeding on seeds and tunneling in the head. Using the same scouting method as described for BSM, walk a W pattern in the field and count moths on 20 plants at 5 sampling sites and calculate an average number of moths per 5 plants. Since female moths lay eggs on the face of sunflower heads, insecticide should be applied during early flowering (R5.1 - R5.3). 

 

Janet J. Knodel

Extension Entomologist

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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