Andy Michel
aphids on soybean leaf, Purdue University photo
For the most part, soybean aphids have been a problem only in odd numbered years. Several other states have broken this two-year cycle, but it has held in Ohio for over 10 years. Recently, we have been noticing the presence of soybean aphids in soybean, mostly in the northern and central part of the state. While the majority of fields have extremely low numbers, a few fields have reached 75-100 aphids per plant. Usually, in even numbered years, non-economic soybean aphid populations are found in soybean—these aphids will provide the migratory populations needed to overwinter on buckthorn and form populations the following year. Additionally, natural enemies such as lady beetles have already responded and are in many of these fields (photo). Keep in mind, the economic threshold to manage soybean aphid is a rising population of at least 250 aphids per plant. While the expectation is that soybean aphid populations will remain under threshold, growers should keep a watchful eye on their fields, especially in late planted soybean fields that may take some time before reaching the R6 stage (when the soybean aphid economic threshold can be increased).
Soybean Aphids fact sheet
Source : osu.edu