Isn't It Too Early For Soybean Aphids?
Jun 24, 2011
Question: I’m hearing reports about soybean aphids already. Isn’t it too early for them to be in fields?
Answer: We’re hearing the same thing, though it is a bit early in the season for them to be showing up in large numbers.That said, we would encourage you to touch base with your local county extension or consulting agronomist to determine what the outlook for aphids is in your area this season. Soybean aphids weren’t a widespread problem in 2010, but late-season build-ups last summer resulted in a number of predictions that they would be more of a problem this season. They are a pest you want to stay on top of. They transmit viruses such as the soybean dwarf virus and soybean mosaic. The economic threshold for aphids is 250 aphids per plant. We use this threshold up until the later reproductive stages, around R4. Some research we’ve seen indicates there could be an economic benefit from using this threshold through R5. You can use a simple speed counting process to determine whether you’ve reached threshold levels—it doesn’t have to take a ton of time and is certainly well worth your effort. The protocol for this process was developed by researchers at the University of Minnesota. For more information on the procedure, go to: soybean aphid counts.