MSU Extension

General harvest comments

Unseasonably warm weather in late September and early October continues to move the harvest season along faster than usual. Red Delicious, Ida Red and Rome are the last prominent varieties left in blocks in the region, and are being harvested in earnest. All three are mature, so the race is on. Most growers expect to be finished by the end of the week or the very beginning of next week, though small acreage of some less prominent late varieties like Fuji and EverCrisp will remain. As a result, this will be the final apple maturity report for the west central region for the 2017 growing season.

Brown marmorated stink bugs are still very low in the area. Areas further south have caught significant numbers in trap lines, but the trap line in west central Michigan is still not catching anything. The same is true for the team in northwest Michigan. This pattern has been fairly typical this season all over Michigan—they do not seem to be showing up in traps until late in the season, probably some time after they start being attracted to apple fruits. We will continue to monitor for this pest through the end of October and into November using our traps, but it is evident our brown marmorated stink bug traps and their interpretations in our region need further refining.

The normal and estimated 2017 peak harvest dates for apple varieties in Grand Rapids, Michigan, is included at the end of this report. While we have historically assumed that we lag behind the Ridge in the west central region, this has not been the case this season. Data in the following tables are based on samples collected from commercial orchards in Oceana and Mason counties. Firmness and starch ranges are observed as low and high mean values. Optimum long-term storage parameters are also included at the end of the article.

Individual variety results

Red Delicious was sampled for the fourth and final time this week, and it is ready to go. Red Delicious is considered mature for controlled atmosphere (CA) storage at a starch index of 2.5, with ideal firmness between 16-18 pounds. Red Delicious in the west central region took a nice jump over the past seven days in maturity, testing at a 3.5 on the starch index scale and still holding onto firmness of just over 16 pounds. Brix also increased nicely to an average of 13.36. However, firmness is close to slipping below the desirable range, and water core also increased noticeably this week at all sites sampled, indicating we are starting to lose quality. Some red bleeding is also starting to show up in the cortex. Growers should get after this variety as soon as possible.

Ida Red was sampled for the fourth and final time this week. This variety held fairly steady over the past seven days, not showing a major difference in firmness or brix. It is now testing at about 4.5 on the starch index, indicating we are still in the prime window of harvest for this variety. Ida Red is not considered over-mature until a starch index of 6, so growers still have some time with this variety assuming quality holds. However, more bleeding started to show up in Ida Red over the past several days.

Rome was sampled for the third time this week. Rome is considered mature for CA storage at a starch index of 3, with an ideal firmness of between 15 and 18 pounds. Rome moved along in maturity nicely over the past seven days, and continues to test mature throughout the region. Firmness is excellent in the variety, it has not been affected by the late-season heat weave like many others varieties.

EverCrisp was tested for the third time this week. We actually saw a slight decrease in the starch index average across sampled fruits, but firmness dropped very slightly and brix rose. Generally, this variety seems to be holding quality extremely well in the field in spite of some difficult weather conditions late in the season this year. Its developing reputation as a late apple with outstanding holding quality seems to be well-deserved thus far. Color has also developed nicely on this variety in the past week. It really seems to creep in late on this variety; two weeks ago it was not an attractive apple, but is now looking nice and red.

Fuji was sampled for the second time this season. Fuji is considered mature for CA storage at a starch index of 3, with ideal firmness of 16-18 pounds depending on desired length of storage. It is considered over-mature at a starch index of 7. We moved along in development slightly from last week, but other than a modest increase in brix, this variety did not move along much. It is in the early stages of maturity, but can easily wait another week for growers who are busy with other varieties. Quality seems to be holding well at this time.

Looking for more? View Michigan State University Extension‘s Apple Maturity page for regional reports throughout the state and additional resources.