EAST LANSING, Mich. — The predicted harvest dates for every weather station are now available at Michigan State University’s Enviroweather website. The 2020 spring cold temperatures generally delayed apple tree development. Most of the state experienced a late bloom except the very southeastern part of Michigan. In general, 2020 predicted harvest dates are a few days later than normal. Most of the state is only a few days behind normal and nearly equal to, or a few days ahead of last year.
A severe freeze on May 9 reduced crop loads for many orchards. For southwest region orchards, relatively calm wind conditions during the freeze hours increased damage in low areas. Most areas bloomed a week late except southeast Michigan, which was a only few days late. Warm weather returned mid- to late May, which sped up bloom. In general, apple blocks have a mix of crop loads with most near average. Blocks with light crop loads will mature 3 or 4 days sooner than the predicted harvest dates. Heavy crop loads will mature up to 7 days later than the predicted dates. If hot stressful weather occurs in August or September, apple maturity will be advanced. The 2020 predicted harvest dates are listed in Table 1.
The normal harvest dates for other varieties are listed in Table 2 for the central southwest Michigan area. The predicted dates for other non-modeled varieties are a rough estimate based on the McIntosh, Jonathan and Red Delicious predicted dates. ReTain application should be applied 30 DBH (days before harvest). Harvista can be applied 3 to 7 DBH. Use Table 2, 2020 for predicted harvest dates for other varieties to time ReTain applications and adjust for varieties and locations.
Table 1. 2020 predicted peak harvest dates.
|Full bloom dates 2020||Predicted harvest dates 2020|
Table 2. Normal and predicted 2020 peak harvest dates for apple varieties in central Berrien County in southwest Michigan based on weather data at the Southwest Michigan Research and Extension Center, Benton Harbor, MI.
|Variety||Normal date||2019 Predicted peak harvest date||2020 Predicted peak harvest date|
— William Shane, Mark Longstroth, Michael Reinke and Katherine East, Michigan State University Extension
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