MSU Extension

General comments

Apple harvest is going very quickly across Michigan. Some larger producers report that they will be done by the weekend (September 29-30) with very little left to harvest in the month of October, which is normally our busiest harvest time. Blocks are generally picking out shorter than expected and fruit finish is poor, resulting in poor pack-outs. This will be the last apple maturity report for 2012.

Southwest Michigan - Bill Shane, Michigan State University Extension

Most apples for wholesale markets have been picked in southwest Michigan. A few apples remain in the tops of trees and are supplying the local retail sales. Golden Delicious, Red Delicious, McIntosh and Fuji apples, in general, had a nice finish this year. Honeycrisp and Jonagold suffered from lenticel disorders, leading to rot problems.

Southeast Michigan - Bob Tritten, Michigan State University Extension

Apple harvest is moving along very quickly this season; growers with a crop are saying that they will be wrapping up harvest in the next week or two. This could be the earliest end of harvest that we have ever seen in the region. Growers are working their way through the later maturing strains of Red Delicious and are picking Idared at the same time. Northern Spy has mostly been harvested. Golden Delicious harvest ended late last week for most growers; they had the nicest finish that growers have ever seen this season. Fuji is not quite ready yet, but will be over the weekend and early next week. Romes are also very close to being mature. Most growers report that they do not have enough Braeburn this year to worry about, but those that do will be picking them in about 10 to 14 days.

Lastly, apple cider continues to taste very good this season, with a sweet, rich, full-bodied flavor. In general, brix levels are up this season in most apple varieties; this is helping to make the blending easier and cider with a good taste. I have had many growers comment on the tremendous amount of sediment in cider this season, especially from apples that have been transported a long distance. This has been true for most varieties, but especially McIntosh.

West Central Michigan - Phil Schwallier and Amy Irish-Brown, Michigan State University Extension

Harvest of Fuji and Rome is finishing up with many growers stating that harvest should be complete by the end of September. There are a few Granny Smiths that need to be harvested. Other very late harvested varieties such as Braeburn were severely hurt by the frost and there are very few in this region.

Northwest Michigan – Nikki Rothwell, Michigan State University Extension

Apple harvest continues throughout the region and quality has been excellent. The recent weather has been unusual (not a surprise this season) and we have had many bouts of hail and sleet. We have not observed substantial damage from the hail events, but fruit has been likely impacted with the multiple days of rain and hail.

We were again a bit surprised this week as there are a few McIntosh orchards that have yet to be harvested. The limited testing showed that the starch is still in the 3.5 range, but color has improved markedly in the past week. Honeycrisp harvest is underway and color of this variety has also improved this week. However, firmness has dropped substantially. Some Jonagold orchards have been harvested, but we did test one block and Jonagold brix is extremely high this year. We have tested apples with an average of 16 brix, but some fruits have been in the 18 range.

Starch indexes are approaching over-mature in Jonagold. Golden Delicious is still testing in the mid-2 range for starch, but the green color is fading to yellow. Ida Red and Rome are still a ways off before harvest. Starch indexes are in the 2 range, and the firmness of both is high. Ida Red color has improved this past week. Empire is in the mature range, starch is at an average of 5.3 and brix levels are in the mid-13s. 

Notes from the 2012 CA Clinic – Randy Beaudry, MSU Department of Horticulture

The MSU Controlled Atmosphere and Storage Clinic was held in Grand Rapids, Mich., at the Amway Grand on August 8. The clinic was sponsored by AgroFresh, who co-organized the event, Storage Control Systems, Pace and Decco. We were very fortunate to have two excellent invited speakers in for the event: Jennifer DeEll from Ontario (OMAFRA, Simcoe) and James Mattheis of Washington State (USDA, Wenatchee). Both speakers spoke on two topics. Dr. DeEll spoke on combining CA and SmartFresh to control storage disorders in Empire and on multiple applications of SmartFresh for Northeast apples. Dr. Mattheis spoke on internal browning in Gala and on CA storage of Honeycrisp apple fruit. Below are a few highlights from their talks.

Dr. DeEll showed that fruit are sensitive to SmartFresh throughout the storage period. Using examples of Empire and McIntosh apples, she showed that a second application of SmartFresh after CA storage could markedly improve fruit firmness retention during the retail holding period. She also showed that a second treatment would reduce internal ethylene content and suppress senescent breakdown in McIntosh. Dr. DeEll also evaluated the effect of delayed CA storage on CO₂ injury susceptibility in Empire. She found that a delay of one to two months reduced CO₂ injury and could reduce core browning in apples as long as the fruit were not previously treated with SmartFresh. However, these fruit were at greater risk of softening. SmartFresh treatment just after harvest in combination with a delay in the establishment of CA resulted in firm fruit with low incidence of CO₂ injury.

Dr. Mattheis’ findings on options for Honeycrisp storage revealed that seven days at 50 degrees Fahrenheit followed by storage at 36 or 39 F almost completely suppressed chilling injury on early harvested fruit, and was also very effective for more mature fruit. Mature fruit benefitted more from the higher storage temperature of 30 F in terms of reduced soggy breakdown and soft scald. Dr. Mattheis also shared that CA (2 percent O₂ and 1 percent CO₂ ) storage was very effective at reducing greasiness and maintaining high titratable acidity. Treatment of the fruit with a seven-day storage delay at 50 F was used for all stored fruit. SmartFresh tended to reduce internal browning after long-term (six months) CA storage as well. Oxygen levels below 1.5 percent were found to be damaging, leading to more internal browning. CO₂ levels above 1 percent also caused internal browning and an increase in the internal cavities associated with CO₂ injury.

Dr. Mattheis recommended harvest at a starch index of 5 to 6, and the use of seven days delay at 50 F to suppress chilling disorders. He also suggested that a CA atmosphere of 2 percent O₂ and 1 percent CO₂ was near optimal, with storage temperatures maintained between 36 and 39 F. He noted that SmartFresh worked very well with Honeycrisp and could be used in air storage or in combination with CA.

Go to the 2012 MSU apple maturity program and reports.