Developing an integrated pest management program for edamame in Virginia

Edamame (Glycine max (L.) Merr.), also known as vegetable soybean, is primarily grown and consumed in Asia. In recent years, the demand for edamame in the United States has risen due to its health benefits as an alternative, plant-based protein. Due to the lack of domestic production, most edamame is imported from Asia. In an attempt to increase domestic production, research efforts have begun in Virginia and other regions to develop cultivars and best management practices for growing edamame in the mid-Atlantic region. Beginning in 2018, edamame trials examining breeding lines and cultivars were conducted to look at their suitability for this region. These varieties were sampled and evaluated for insect and disease complexes as well as their implications on plant yield and quality. Most of the insects and diseases that were found were very similar to pest complexes commonly found in cultivated soybeans in Virginia. However, due to edamame being marketed as a vegetable, insects and diseases that caused unsightly blemishes or damage to the pods or seeds were most concerning. Multiple insects and diseases were present but some of the most important insects and diseases we observed from 2018-2020 were pod feeding stink bug (Hemiptera: Pentatomidae), as well as the diseases like purple seed stain, Cercospora kikuchii, and bacterial pustule, Xanthomonas axonopodis pv. glycines. From 2019-2021 an integrated pest management study was conducted to determine best management practices for minimizing insecticide applications while applying them at thresholds to control key pests. In three growing seasons, I was able to determine that pesticides can be limited prior to flowering while insecticide inputs will need to be increased after flowering to protect the pods from pests, specifically stink bugs. Additionally, from 2019-2021 insecticide and fungicide field trials were conducted to test different pesticides on their efficacy against pod damaging pests and diseases. The growing seasons between 2019 and 2021 resulted in varying insect and disease pressure that led to inconsistent results. However, insecticides such as cyclaniliprole and sulfoxaflor performed well compared to other treatments. Lastly in 2020-2021, corn earworm (Helicoverpa zea [Boddie], Lepidoptera: Noctuidae), an important soybean pest and most likely a major pest of edamame, was tested for pyrethroid susceptibility and resistance across the state using a bean-dip bioassay. Pyrethroid efficacy to control this pest across Virginia seemed to vary by location and year, however, the bean-dip bioassay proved to be a time-efficient strategy for further monitoring these populations in the coming years.