By Nicolle Ritchie and Angie Gradiz
Weather
Temperatures remained fairly constant over the past week with highs in the 80s. Scattered showers provided small amounts of precipitation until yesterday, July 9, when parts of southwest Michigan received over 1 inch of rain. Other parts of southwest Michigan did not receive any precipitation over the past week and have been drier than normal all season and are running a deficit of about 5 inches.
Scattered showers throughout the upcoming week will bring potential rainfall this weekend and again in the middle of next week. Temperatures will increase slightly, and potential evapotranspiration will be above normal.
Crops and pests
Soybeans are in late vegetative stages and early reproductive stages. A plant with one flower anywhere on the stem is at R1, and if the plant has at least one open flower in the top two nodes, it is at R2. R3 starts when a pod in one of the upper four nodes is 3/16 inches long, and some soybeans in southwest Michigan have already hit R3. Fungicides to prevent white mold should be applied between R1 and R3, with data showing higher efficacy when applied closer to R1. Risk models show a low white mold risk for the next several days.
Corn started to put out tassels in some fields this week, and detasseling has started on select seed corn fields. Most corn is in late vegetative stages. Tar spot was confirmed in Cass and Eaton counties yesterday, July 9. As tar spot is found closer and closer to home, remember that the best timing for a single fungicide application is between VT and R3-4. Risk models show a low tar spot risk for the next several days.
As tasseling approaches, western bean cutworm moths will be searching for plants close to tasseling or freshly tasseled. Scout for egg masses in the upper two thirds of the canopy by walking with the sun backlighting the plants. Egg masses will appear as dark shadows on the leaves.
Source : msu.edu