By Josie Dillon and Amaya Atucha et.al
Hello fruit growers, we are excited to share apple and grape scouting updates with you this year through the Wisconsin Fruit Newsletter. Recent rain events have pushed along spore maturity and disease infection events for apple scab and cedar apple rust in apples, and Phomopsis cane and leaf spot and black rot in grapes. Insects are more active as well, with several growers reporting codling moth trap captures and observations of plum curculio and grape phylloxera. As a reminder, this newsletter will cover apple and grape phenology, general scouting observations, and includes an overview of degree day accumulation. Growers can reference the Midwest Fruit Pest Management guide for further information on pest management best practices.
Growing Degree Day (GDD) Accumulations
Below displays the GDD accumulations from April 1 through June 18 for the current and last two seasons. This data is collected using the NEWA website. You can visit their “About degree days” page to learn more about the concept of degree days as well as the formulas utilized for calculations. We remain slightly behind in West Madison and PARS compared to the last two years. Growers have reported signs of cane death, likely due to cold temperatures in January with no to very little snow cover.