Pan trapping of soybean aphids, Aphis glycines (Matsumura) and how it can relate to an outbreak

Soybean aphids, Aphis glycines(Matsumura) can be a major pest in soybeans, Glycine max (L.), and cause millions of dollars in losses per year. Current practices to monitor soybean aphid levels can be very labor-intensive due to the time required to count aphids on numerous plants in the field. During the summer of 2008 pan traps were set up in two fields and during the summer of 2009 in four fields to evaluate two known aphid sex pheromones, Z,E- nepetalactone, and a mixture of Z,E- nepetalactone/nepetalactol. A third field studied in 2008 compared the two previous pheromones, along with catnip oil, benzaldehyde, and mixtures of those compounds, for seven treatments in all. Each treatment was replicated three times in each field in 2008 and in one field in 2009, with the other fields containing four replicates in 2009. Pheromone lures were rotated through the field each (weekly) trapping period. Pans were filed with a mixture of propylene glycol and water and collected weekly when the lures were changed. Previous work done by Zhu et al., has shown that trapping of alate soybean females can be an indicator of population growth that is 1 or 2 weeks ahead of an outbreak. With this method we could possibly provide better forecasting, reduce yield losses and provide cost savings.