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Volume 9 -- 2001 Healthy Fruit is written by Jon Clements, Ron Prokopy, Dan Cooley, Arthur Tuttle, Gerald Lafleur, Wes Autio, Bill Coli, Duane Greene, Bill Bramlage, and Sarah Weis and is presented with the cooperation of New England Fruit Consultants and Polaris Orchard Management. Publication is funded in part by the UMass Extension Agroecology Program, grower subscriptions, and the University of Massachusetts IPM Program. A text version can be e-mailed to you if you contact Doreen York. Please cite this source if reprinting information. |
Welcome rain arrived in localized areas during the past week. More is needed. In orchards where irrigation is lacking and there has been no significant rain, trees are stressed. This may manifest itself in heavy drop, earlier ripening and slowed fruit growth. So far drop has been excessive only on trees receiving ethephon, even when a stop drop was used. Monitor drop and maturity using starch iodine indices. Honeycrisp in some blocks were harvested on September 4, which is several days earlier than in previous years. Starch iodine index of monitored blocks of Marshall McIntosh averaged 3.5, which is higher than normal for this time of the season. Red color development is good, and a favorable weather forecast for the next few days should improve this even more.
By the time you read this, McIntosh harvest will have begun in most Massachusetts orchards. Although no year is ever 'normal,' this growing season in particular may present some challenges in terms of harvest management. You are advised to carefully monitor all your blocks, as the possibility of uneven ripening and/or premature drop is definitely out there. An early bloom and hot weather during August suggests ripening may be a little early. Recent cooler temperatures ought to favor color development, so there is no need to procrastinate!
Speaking of warm weather, a recent article in Kevin Iungerman's 'Northeast Tree-Fruit' (the commercial tree fruit newsletter of Cornell Cooperative Extension's Northeaster NY Area Fruit Program) notes that McIntosh apples may be predisposed to internal breakdown because of the heat we experienced last month. Such a warning is based on the Cornell Publication 'Storage of Fresh Market Apples,' wherein it explains during seasons of ten or more consecutive days in August and September having maximum temperatures greater than 840 F., and dry conditions persist, then McIntosh breakdown is a likely problem. Such conditions occurred in many of our orchards, however, good pre-harvest weather (i.e., cooler temperatures) will help. If you have a Mac orchard or block in a warmer location and it has been dry, or you have experienced McIntosh breakdown before, it's suggested you avoid long-term CA storage of this fruit. Such fruit should be destined for immediate sales, or if placed in CA storage, then put it in an earlier opening room and make sure it is not picked late. Cornell's research has also shown that a post-harvest calcium chloride dip will reduce the incidence of McIntosh breakdown in susceptible fruit. (Note: if you'd like a copy of Iungerman's article, let us know.)
Here are some specific notes for currently harvested apple varieties:
McIntosh harvest has begun. Marshall McIntosh have responded well with good color development to ethrel treatment, however, they have dropped quickly if not harvested promptly. At the UMass HRC in Belchertown, a sample of several Mac strains tested on 5-Sept averaged 55% red skin color, 16 lbs. flesh firmness, 12% soluble solids, and 3.5 on the starch-index scale. Fruit was clearly ready for spot-picking based on color, and although drop was minimal (mostly push-off), fruit separated easily from the spur. As noted in a previous Healthy Fruit, the predicted last harvest date for McIntosh destined for CA storage is 21-Sept in Belchertown, leaving just two weeks to harvest the majority of Macs.
Gala harvest normally coincides with McIntosh, however, Gala is more variable and needs three or four harvests based on maturity. Highlighting this difference in maturity, a sample of Gala picked 5-Sept at the UMass HRC ranged from 1 to 6 on the starch-index scale! (It average 3.5, exactly the same as McIntosh.) The best way to pick Gala for fresh market is based on background color which moves from green (very immature) to yellow (getting there) to cream-color (starch-index 5 or greater). A Gala block visited last week (29-Aug) in SE Massachusetts was visibly ready for a first pick.
Honeycrisp is surprising in more ways than one. Anecdotal reports from the Hudson Valley indicate maturity is more advanced than expected and harvest is well underway there. Not surprisingly then, at the UMass HRC, Honeycrisp picked and tested on 5-Sept were mostly 6+ on the starch-index scale. They tested from 15 to 18 lbs. flesh firmness and 13-14% soluble solids. Significant watercore and internal breakdown (browncore) were observed in fruit harvested from younger, lightly cropped trees. Most agree that Honeycrisp should be harvested at a starch-index of about 5 for best flavor, however, the fruit is variable in ripening and shows no external signs of maturity, other than pre-harvest drop! Honeycrisp is certainly living up to its role as a problematic variety, and you are advised to keep a close watch on it. Correction to 8/28/01 Healthy Fruit Carzol was listed as a control option for white apple leafhopper (WALH) on apples at this time. An alert reader pointed out the current label restricts it's use to pre-bloom. Therefore, Carzol IS NOT a control option at this time. Provado would be the best choice if treatment is necessary to reduce a nuisance population of WALH before harvest.
Carzol was listed as a control option for white apple leafhopper (WALH) on apples at this time. An alert reader pointed out the current label restricts it's use to pre-bloom. Therefore, Carzol IS NOT a control option at this time. Provado would be the best choice if treatment is necessary to reduce a nuisance population of WALH before harvest.
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©Copyright 2001 University of Massachusetts Amherst, Massachusetts, 01003. (413) 545-0111. Produced and maintained by the UMass Fruit Team. This is an official page of the University of Massachusetts Amherst campus. |
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