End of primary apple scab season in east Michigan
Apple growers with clean blocks can now relax their control measures for apple scab for the rest of the 2016 season.
With rain finally this morning, April 16, at my apple scab spore trapping location (after 11 days without a rain event), I am not catching any apple scab spores and am therefore calling an end to primary apple scab season in east Michigan for the 2016 growing season. This has been an unusual apple scab season, as I was catching apple scab spores much earlier than normal, followed by several periods without any precipitation to trigger spore release. So, even though we had early spore release, with the dry weather I am calling an end to primary apple at about the usual time of the season, that being mid-June.
Apple growers with clean blocks can now relax their control measures for apple scab for the rest of the season. For growers with just a touch of scab in certain blocks, you should continue to keep on top of the situation. Remember, if you do have scab showing up, it takes two or three fewer hours for secondary scab infections to get started than it does for primary scab. Do a good job of scouting all of your blocks for apple scab lesions before you stop spraying.
Visit the Michigan State University Extension Fruit & Nuts News website for fruit-related articles. The Enviroweather website is a great resource on weather, crop and pest information. If you are looking for MSU Extension publications and bulletins, visit our MSU Extension Bookstore website to find them online.