Apple maturity testing will occur weekly for the Grand Rapids, Michigan, region through the end of harvest. Reports will be released each week following the Michigan State University Extension fruit team maturity calls on Wednesday mornings.
Currently, Golden Delicious, Red Delicious, Rome, and Mutsu are being harvested. Some blocks of Idared and Aztec Fuji have also been picked. Pink Lady and EverCrisp were sampled this week, and some sites showed fruit mature and ready for harvest.
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Harvest dates are tracking closer to last year, with varieties about two weeks ahead of normal. High heat in August and September advanced degree-day accumulation and fruit maturity. Growers are advised to monitor blocks closely and communicate maturity information to packers and processors to ensure optimal storage and fruit quality.
As maturity advances, pre-harvest management products may be required to maintain quality and manage labor. For later-maturing varieties, aminoethoxyvinylglycine (AVG; ReTain) is recommended at 28, 14, or 7 days before harvest. For 1-MCP (Harvista), applications are recommended at 7 or 3 days prior to harvest.
The weather over the past week was unseasonably hot, followed by a storm system on October 6 that lowered temperatures. Recent averages reported by the Hart Enviroweather station included lows in the upper 30s to low 40s Fahrenheit and highs in the 60s. Forecasts suggest similar conditions, which are favorable for color development in later varieties such as Aztec Fuji, EverCrisp, and Pink Lady. Rainfall totals from the October 6 storm included 0.72 inches in Sparta, 0.54 inches in Belding, and 0.85 inches in Grant. Additional rain is forecast later this week.
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Variety sampling results
Fuji (including Aztec Fuji) fruit from Sparta averaged 73% red color, 18 pounds firmness, starch at 3.7, and 13.1° Brix. The fruit is mature.
Red Delicious fruit from Sparta averaged 93% red color, 17.7 pounds firmness, starch at 3.7, and 13.8° Brix. The fruit is mature.
Idared averaged 81% red color, 15.5 pounds firmness, starch at 3.3, and 12.4° Brix. The fruit is nearly mature.
EverCrisp from Sparta and Grant averaged 58% red color, 22.1 pounds firmness, starch at 3.3, and 15.1° Brix. The fruit is nearly mature.
Pink Lady from Grant averaged 47% blush, 16.5 pounds firmness, starch at 6.6, and 14.4° Brix. Some fruits are mature, though maturity varies across sites.
Braeburn averaged 71% red color, 22.8 pounds firmness, starch at 3.0, and 12.4° Brix. The fruit is nearly mature.
Granny Smith averaged 11% blush, 17.1 pounds firmness, starch at 3.1, and 10.1° Brix. The fruit is not yet mature.
Samples are untreated with ReTain or Harvista unless otherwise noted and were collected from three Kent County sites.
To view the full report, click here.
For more information:
Michigan University
Tel: +1 517 355 1855
www.canr.msu.edu
