OFN Updates

June 25, 2020

In advance of establishing the On-Farm Network trials evaluating field pea fungicides, we’ve been using the Fungicide Decision Worksheet for Managing Mycosphaerella Blight in Field Peas. Peas are scouted regularly to keep an eye on how things are progressing and to determine optimal fungicide timing. Here’s a video on how we use this worksheet in the field.

For example, when we first visited one of our pea fungicide trials near Brandon on June 19 the rows were still open, and plant stand counts were normal. At this stage of V10, there was no leaf wetness and there were no Mycosphaerella symptoms in the plant canopy. Some bacterial blight symptoms were evident, as this field saw some of the heavy winds and rains earlier in spring. Environmental damage to the plants, or mechanical damage, allows entry points for bacterial blight infection.

Bacterial blight symptoms showing up in field peas near Brandon. Note the water-soaked appearance of the lesion and how it does not cross leaf veins. Bacterial blight infection in this field followed environmental damage from high winds and rains. This photo was taken on June 19, 2020.

We visited this same field 6 days later on June 25. In that time, rows had closed and peas were now at V12 with the very first flowers opening up. With row closure there was more lush growth and we were noticing the very first symptoms of Mycospharella setting in. Now, the forecast was predicting light showers (less than 1mm) for the next few days. This increased the overall score to 55. While not yet at the break-even scoring of 65, we planned to spray this trial on the next Monday, June 29, anticipating that conditions over the next few days would put us over the edge. With more flowers opening up, we expect this application to be timely.

Early Mycosphaerella blight symptoms showing up in On-Farm Network pea fungicide trials. Note the purple freckling on the leaves. This photo was taken on June 26, 2020 near Warren, MB.