Soybean aphids have begun to establish colonies in soybean fields across southern Minnesota, including areas like St. Paul and Lamberton. While other crop-related concerns may currently be at the forefront of your mind, it is crucial to remember the significance of scouting your fields as June progresses. Presently, aphid infestations remain below thresholds that necessitate insecticide treatment for yield protection.
The success and size of aphid infestations on soybean crops will depend on various factors, including weather conditions, soybean plant quality (influenced by growth stage, moisture, other pests, and diseases), and natural enemies such as predators, parasitic wasps, and diseases. Considering these multifaceted elements, it is challenging to accurately predict the overall impact of soybean aphids in Minnesota for 2023, let alone their development in individual fields. Hence, regular field scouting remains essential to determine the need for insecticide applications to safeguard soybean yields from aphid damage.
During early season (typically starting in mid to late June), focus on indicator fields with high aphid activity. As the season progresses, scout all fields regularly, ideally every 7-10 days. Use a threshold of 250 aphids per plant to determine optimal timing for insecticide application against soybean aphids, preventing infestation escalation rather than yield loss occurrence.
When considering management options for soybean aphids, it is crucial to be aware that many aphid populations have developed resistance to pyrethroid (group 3A) insecticides. Additionally, it is important to recognize that some insecticides used to control aphids may also harm beneficial predatory insects and parasitic wasps. These wasps play a role in aphid control by leaving behind mummified aphids after eliminating them. These mummies, distinguishable by color (tan vs. black), can provide valuable insights into the types of wasps involved in aphid predation.
Staying vigilant, monitoring aphid infestations, and implementing appropriate management strategies are vital steps in preserving soybean yields and mitigating the impact of soybean aphids on Minnesota fields.
Photo Credit: gettyimages-gilaxia
Categories: Minnesota, Crops, Soybeans