HOPEFULLY, YOUR CROPS are off to a good start. To ensure the continued success of soybeans, pest and disease scouting is important until soybeans reach their reproductive growth stages.
When you’re scouting, it’s important to check stand and plant uniformity. Making these assessments throughout the growing season can help you identify when and where stand losses are occurring and what may have caused them. As you scout each month, go back to the same areas of the field to see how stands are changing over time with the same group of plants.
Scouting for aphids should begin in mid- to late June by the late vegetative stage of soybean growth and continue on a weekly or near-weekly basis until the R5 stage.
Scout more intensively in late June to early July. Estimate population densities on 20 to 30 plants per field, covering at least 80% of the field. Identify heavily infested fields and monitor them closely.
The late vegetative and early reproductive stages are when soybean aphid populations tend to increase the most. This is also the stage where the yield return on treatment is the highest. So long as populations are at threshold and actively increasing, treatment should be considered.
Be sure to check the entire plant, including the undersides of leaves, petioles and pods. Aphids move from the top to the middle or lower areas of the canopy at this stage.
Insecticide treatment decisions should be based on an economic threshold of 250 aphids per plant…