By Scout Nelson
The Dectes stem borer, a common insect pest in South Dakota, is becoming an increasing concern for sunflower growers. Recent data from the National Sunflower Association shows infestations have grown by nearly 30% between 2019 and 2023, posing a growing threat to the state’s sunflower fields.
The Dectes stem borer primarily affects sunflowers but can also infest soybeans and other broadleaf plants. Adult beetles lay eggs in sunflower stems during the summer, and larvae tunnel through the stalks as they develop.
This internal feeding weakens the stem, making plants more likely to break or lodge before harvest. Such damage can lead to significant yield loss and reduce overall crop quality.
Researchers and agronomists at South Dakota State University, supported by the National Institute of Food and Agriculture, are studying the pest’s lifecycle to create better control strategies.
They emphasize that understanding when adult beetles emerge and when eggs are laid helps farmers make timely management decisions.
Farmers are encouraged to scout their fields regularly, checking for signs of stem tunnelling and wilting. Management options include rotating crops, delaying harvest until after larvae pupate, and using pest-resistant sunflower hybrids where possible.
Some producers also use integrated pest management (IPM) techniques to balance natural predators with chemical control, ensuring sustainability.
The increase in Dectes stem borer populations highlights the need for continued research and farmer education. Preventive measures and early detection remain key to reducing infestations and protecting South Dakota’s sunflower production.
This ongoing research, funded through grant 2024-03471, focuses on protecting sunflower yields, promoting sustainable practices, and ensuring the long-term success of South Dakota’s vital sunflower industry.
Categories: South Dakota, Crops, Sustainable Agriculture