By Bob Tritten
General apple harvest comments
The pace of apple harvest is quickly picking up steam. Growers are waiting for later and older strains of Gala to color and size to finish on this variety. In the meantime, growers have moved on to the second, third or final picking of Honeycrisp and are stripping McIntosh. Early Fuji is now ready for harvest. Empire, Jonathan, Jonagold and Golden Delicious are quickly approaching maturity. I did not sample Gala and McIntosh this week as I felt we were at their peak harvest window in last week’s sampling.
Warm weather of last week slowed color development for many varieties; however, light frosts of Saturday, Sept. 14, and yesterday morning, Sept. 17, have helped to reverse this. Overall, fruit color is a challenge so far this season. In areas where rainfall has been short, fruit size has been a challenge for several varieties, notably Gala, some McIntosh strains and Jonathan.
Apples are picking easy this week, however fruit drop is not a problem. I am concerned about the potential of fruit drop if we have a windstorm. Most fruit that I see on the ground have been pushed off the tree from neighboring fruit or limbs. Bitter pit remains a problem in Honeycrisp. This week some growers are seeing a fair amount of fruit that is rotting on the tree from black rot. Harvest labor is running short for most apple growers now that harvest is in full swing.
Apple maturity in southeast Michigan for apples harvested on Sept. 16, 2013
Variety | % Fruits with Ethylene over 0.2 ppm (range) | Color % (range) | Firmness lbs. (range) | Starch (range) | Brix % |
Honeycrisp | 100 | 77 (59-94) | 13.9 (12.8-14.9) | 4.5 (2.2-6.3) | 12.4 |
Early Fuji | 50 | 84 (50-93) | 16.0 (14.2-19.1) | 3.7 (2.0-5.0) | 12.6 |
Empire | 15 (0-30) | 69 (62-75) | 17.9 (16.4-17.3) | 2.3 (2.2-2.3) | 10.4 |
Jonathan | 30 | 81 (70-100) | 16.3 (14.2-19.5) | 4.2 (3.0-6.0) | 11.4 |
Jonagold | 15 (10-20) | 60 (36-83) | 17.6 (17.5-17.7) | 2.9 (2.4-3.3) | 12.5 |
Golden Delicious | 0 | 11 (10-11) | 18.8 (14.9-15.8) | 4.2 (3.0-5.3) | 12.0 |
Individual variety results
Honeycrisp were sampled for the third week of the season. Remember that the most mature fruit has already been harvested in the first few pickings, thus the sampled fruit that is left on the tree is fruit that was too green in earlier harvests. As with all samples taken for the apple maturity program, I collect the most mature fruit from the outside of the tree. Honeycrisp is a variety that requires multiple pickings, and this week growers are in their second, third or fourth picking.
Fruit on the inside of the tree are starting to mature. Again this week all the fruit had internal ethylene levels greater than 0.2 parts per million (ppm). The color of fruit sampled from the outside of the tree is about the same as last week at 77 percent. Fruit firmness has dropped over a pound to 13.9 pounds this week. The starch removal index is 4.5 with a brix of 12.4 percent. There is more bitter pit showing up in Honeycrisp than any other variety so far this season.
Early Fuji was sampled for the third week of the season with 50 percent of the fruit showing internal ethylene levels greater than 0.2 ppm. The color has improved from 60 percent last week to 84 percent this week and the fruit are firm at 16.0 pounds. Fruit starch removal index is 3.7, up from 2.4 last week. The brix is 12.6 percent. Early Fuji is ready for harvest at this time.
Source:msu.edu
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