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Tree Fruit E-Alert 10/13/20

Tree Fruit E-Alert ~ October 13, 2020 In this E-Alert

Frost Observed Monday Morning in Clinton County, and Mitigating Fruit Damage

Champlain Valley Harvest Maturity Program Report: Week 8

Frost Observed Monday Morning in Clinton County, and Mitigating Fruit Damage

Mike Basedow, CCE-ENYCHP

Pockets of frost were observed in portions of Clinton county Monday morning. While the forecast for the rest of the week appears to be milder, below are a few reminders about harvesting frozen fruit if we continue to experience these conditions:

Fruit injury generally begins to occur between temperatures of 28.5 and 28°F.

While there are many variables influencing frost damage to fruit, a general rule of thumb is to anticipate some quality loss if fruit are subjected to 28°F for four hours or longer.

Injury is also impacted by temperatures following the cold event. Expect more damage if temperatures warm rapidly following the frost.

If fruit are frozen, do not handle them until they have completely thawed, as they are extremely susceptible to bruising while frozen.

Fruit left out in bins overnight and subjected to the cold should be kept shaded, as exposure to direct sunlight can further increase damage.

Fatally frozen fruit will exhibit flesh browning after thawing once the temperature has risen enough for oxidation to take place. This browning can appear at the skin surface or below, and generally takes about 24 hours to appear, longer if temperatures remain cold. After the apples have warmed, cut fruit open and inspect them. If browning appears, the fruit is unfit for use.

Where browning is not observed following a frost event, fruit quality should still be considered questionable for long-term storage. If you do plan to store fruit impacted by these temperatures, store them separately and monitor firmness regularly for unacceptable firmness loss.

For additional information on handling fruit subjected to frost events, see the article by Dr. Jim Schupp of Penn State University in our most recent Tree Fruit News.

Champlain Valley Harvest Maturity Program Report: Week 8

Mike Basedow and Andy Galimberti, CCE-ENYCHP

This week we are reporting on NY-2.

This week's samples were collected Monday, October 12th and were processed the same day. Fruit were picked from orchards in Peru.

Sample size is 10 fruits picked for average maturity, from multiple trees, on both sides of the row.

As blocks receive harvest PGR’s, we will update their treatment in the final data column so you can better compare against your own blocks.

We are also presenting data from previous seasons for blocks where we have them.

Due to the large amount of variability associated with strains, root stock selections, planting systems, the widespread use of ReTain, Harvista, ethephon, and local orchard microclimates, it is impossible to sample and process enough locations to make specific harvest recommendations. ENYCHP HMP data is meant to be used as a general indicator of apple harvest maturity, and nothing more.

Weekly Summary of Fruit Maturity Progress

NY-2 for 10/12/2020

Comments: Relative to this week last season, firmness in block 1 is reduced and size is slightly smaller, while brix and color development are similar. SPI is further advanced. In block 2, fruit are slightly firmer than last season, and SPI is slightly more advanced. Brix and color development are similar.

For NY-2, aim for a minimum of 3/4 dark red color. Target firmness is 16-20 pounds. Target brix is 12-13%. The starch pattern index (SPI) is recommended at 3-5, but starch is unreliable, and is difficult to read in this variety. There should at least be minimal varietal flavor if flavor is to develop in storage, however, if this variety is to be put into long term CA, err on picking on the earlier side.

The next sampling date is Monday, October 19th. We will continue testing the ReTain treated NY-2 if they have not yet been picked by then. Contact me if you’re concerned about a particular block and would like me to take a closer look.

Quick Links to Tree Fruit Resources on the Web: ENYCHP - Cornell Cooperative Extension Eastern New York Commercial Horticulture Program

Cornell NEWA Website for Weather Info, Computer Models, Pest Management

Scaffolds Fruit Journal, edited by Dr. Art Agnello, Posted Weekly around 3:00pm Mondays

Dana Acimovic’s Blog on Hudson Valley Laboratory Horticultural Research

Peter Jentsch’s Blog on Eastern New York Entomological Challenges

Dr. Srdan Acimovic’s Blog on Eastern New York Pathological Challenges

PERC Training Resources Pesticide Education Resources Collaborative, WPS Training resources

NYSPAD Portal, DEC website with up-to-date information on pesticide materials (replaced PIMS)

Cornell Crop and Pest Management Guidelines

Cornell Fruit Resources Website