Stalk Borer in Soybean
Crop Damage: Common stalk borers (Papaipema nebris) occur from the Atlantic Coast westward to the Great Plains in the U.S. They are also found in southern Canada and Mexico. Larvae bore into soybean stems and tunnel upward. Tunneling destroys the growing point and causes wilted leaves and petioles. Stalk borers lay their eggs in the fall, typically on grasses or weeds along the edges of fields. Eggs hatch in the spring, and larvae feed on plants in the field edges before moving into the crop.
Stalk borer injury in soybean.
Adam Sisson, Iowa State University
Pest Description: Young larvae have a thin cream-colored band along the top. A characteristic brown to purple band starts at the segment behind the thoracic legs and covers four segments. The remaining segments have alternating brown and cream bands that run the length of the larvae. Full-grown larvae are 2 inches long with uniform brown to gray coloration. Adult moths ranges from light to dark brown with a jagged line across the forewings. Males have two sets of light spots and females have dark spots.
Stalk borer tunneling in soybean stem.
Daren Mueller, Iowa State University
Stalk borer adult. The orange arrow shows the jagged line and blue arrows show light spots (male).
Mark Dreiling, Bugwood.org
Scouting and Management: There are no established scouting or management guidelines for stalk borers in soybeans. Infestations are often limited to the first few rows and may occur shortly after plant emergence to late vegetative stages. If you notice wilted plants, slice open the stems and look for the stalk borers. Neighboring plants often compensate for the gaps left by dead plants that were infested by stalk borers. Therefore, yield losses have not been documented. If stalk borers become a recurring pest, manage grass and weeds in borders as they attract adult moths.
Developed and reviewed by Carol Pilcher, Iowa State University and Robert Wright, University of Nebraska-Lincoln, with support from the United Soybean Board.
Stalk borer tunneling in soybean stem. Photo by Daren Mueller, Iowa State University.
Stalk borer adult moth. Photo by Mark Dreiling, Bugwood.org.
Wilted soybean plant. Photo by Adam Sisson, Iowa State University.
Gallery images courtesy Daren Mueller, Iowa State University; Adam Sisson, Iowa State University; and Mark Dreiling, Bugwood.org.
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