(peel) arc often linked to climatic conditions during the growing sea- son and are initiated when a partic- ular metabolic system(s) exhibits strcss- induced hysteresis. These include russet, staining, cracking, splitting, flecking, bitter pit, blotch, lenticel marking, radiation injury, delayed sunscald, superficial scald, and Soft scald (Mehcriuk et al., 1994; Pierson et al., 1971; Porritt et al., 1982). Together, these disor- ders may render unmarketable as niuch as 20% of total production. Considering that the value of apples in Washington state alone in 2006 was $1.4 billion (National Agricul- Preharvest Lipophilic Coatings Reduce tural Statistical Service, 2007), reduc- Lenticel Breakdown Disorder in 'Gala' Apples ing the loss due to physiological disorders is of significant economic importance. " 3 Eric A. Curry '14 , Carolina Torrcs , and Luis Ncubaucr Since 2000, lenticel breakdown disorder (LR) has been a high priority area for research investigations in the ADDITIONAL INDEX wons. Mt1us xdomestici, physiological disorder, storage, cuticle, microcracking, wax, lipids, 'Fuji', 'Granny Smith', 'Golden Delicious' and apple growing regions of the United States. LB symptoms are not SUMMARY. Lenticel breakdown disorder (LB), most prevalent on 'Gala' (Malus x visible at harvest nor are they usually domestiot) apples, especially in arid regions, has also been observed on other apparent on unprocessed fruit after common cultivars. Depending on the preharvest environment, fruit maturity, and storage. It is usually after typical frLlit length of storage, LB usually appears as one or more round, darkened pits, centered ymp- on a lenticel, ranging in diameter from 1 to 8 mm. Symptoms are not visible at processing and packing that s harvest nor are they usually apparent on unprocessed fruit after storage. However, toms are fully expressed (Fig. 1). following typical fruit processing and packing, symptoms are fully expressed after Particularly frustrating for the ware- 12 to 48 h. Because the 3 to 4 weeks preceding 'Gala' harvest are usually the hottest house is that it may take up to 48 It for and least humid, we theorized that desiccation stress was a main causative factor. 1,11 to appear after fruit have been Thus, several unique lipophulic formulations were developed that might reduce packed (E.A. Curry, personal obser- desiccation potential during this period of hot and weather and rapid fruit vation). If symptoms are detected enlargement. Emulsions of lipophilic formulations were applied to whole trees at before shipment, there are often sig- various dosages and timings. In 2005, using a single handgun application 1 day nificant repacking costs; if unde- before harvest, the best treatment reduced LB by about 20% in fruit stored 90 days tected, the negative impact on repeat at -1 °C. The following season, the best treatment from a single handgun application 7 days before harvest reduced LB by 35% after 90 days at -1 °C, whereas sales can be lasting. 3 weekly applications beginning 3 weeks before harvest reduced LB in similarly The distinctive features of LB stored fruit by as much as 70%. In 2007, the best single treatment applied 1 week are: 1) it is not visible at harvest, 2) before harvest using a commercial airblast sprayer reduced LB by almost 50% after symptoms on unprocessed fruit in 90 days at -I °C. storage are not visible, 3) symptoms are expressed mainly after typical pro- n apples, development of physio- during storage. Disorders related to cessing (dump tank, washing, waxing, logical disorders is a function of dysfunctions or aberrations in the and packing), 4) pitting is round and J many components, including cul- development of the epidermal tissue centered on the lenticel, 5) little if any tural management, growing environ - ment, fruit maturity, and conditions Units To convert U.S. to SI, To convert SI to U.S., Mention of a trademark, proprietary product or multiply by U.S. unit SI unit multiply by vendor does not constitute a guarantee or warranty char kPa of the product b the U.S. Dept. of Agriculture and y 29.5735 II oz ni, 0,0338 does not imply its approval to the exclusion of other 0.3048 ft 01 3.2808 products or vendors that also may be suitable. 3.78i4 gal L 0.2642 'U.S. Department of Agriculture, Agricultural 9.3 540 gal/acre L-ha 0.1069 Research Service, Tree Fruit Research Laboratory, 2.54 inch(es) cm 0.3937 1104 N. Western Avenue, Wenatchee, WA 98801 25.4 inch(es) mm 0.0394 'PACE International LLC, 5661 Branch Road, inch cm2 0.1551) 6.4516 Wapato, WA 98951 mm2 0.0016 645). 1600 incls2 'Pace international I.LC, Av. Am. Vespucio N. 2680, 4.4482 hf N 0.2248 Ofleina N. 101, Conchali Santiago-Chile, Chile micron Am ppm 4Corresponding author. E-mail address: eric.curr@ ars.usda.gov . (°F-32) ± 1.8 'F IC 1.8 x°C) + 32 690 October-December 2008 18(4) WA ___ S * Fig. 1, Lenticel breakdown (LB) disorder on 'Gale Gala' (A), 'Golden Delicious' (B), 'Royal Gala' (C and D), and 'Imperial Gala' (E) apples. Insets in A and B show - .-. close-up of pitted lenticels. , corking of the cortex tissue is evident, Initial studies were focused on and 6) there is a cavity underlying the poststorage processing, and a number sunken pit. It is different from jon- of factors were identified that, if athan spot and lenticel spot in that modified, could significantl y reduce, s V^C^_ pitting is always present and usuall y but not eliminate, svniptom expres- -. progressive with increased time in sion (Curry, 2003). Importantly, this A •' .. ,. storage. earlier work established that certain Although prevalent on 'Gala' orchards (or blocks within orchards) Fig. 2. Pitted lenticel (similar in size to apples, especiall y 'Royal Gala', LB showed no propensity for LB, that shown in Fig. 1E) from a 'Royal has also been observed on 'Fuji', and whereas others were highl y suscepti- Gala' apple viewed perpendicular to the to a lesser degree on 'Granny Smith', ble. Our efforts then focused on fruit surface (A). Dashed line indicates that fruit flesh was cut vertically 'Golden Delicious' (Fig. 1B), and preharvest environment. through the center of the pit with a 'Delicious'. Early symptoms on Previous studies showed that single-edged razor to show one-half of packed fruit from regular atmosphere water vapor permeance of apple the pit in water (B), and the other half (RA) storage are visible in angled cuticle in storage was linked to cuticle of the pit freeze-dried and examined light as slight indentations in the microcracking (Maguire etal., 1999). using scanning electron microscopy epidermis about 1 to 2 mm, usually This, together with our ensuing ob- (C). Micrograph in C is a digital mirror symmetrical and centered on a lenti- servation (E .A. Curry, unpublished image to correspond with the picture in ccl, without any darkening. With data) that fruit subject to conditions B. time, the depth of the dimple of high desiccation potential during increases and the pit often becomes the final weeks of fruit enlargement Our objective in this series of trials progressively darker. The darkening had a greater propensity to develop was to determine if preharvest topical appears to he largely a function of LB, led to the hypothesis that re- application(s) of hipophilic coatings how many layers of cells have desic- ducing water vapor permeance of would reduce the incidence and/or cated, thereby compressing the cell the cuticle preharvest by applying severity of LB in 'Gala' apples in RA walls, and the degree of phenolic a lipid-based, hydrophobic coating storage. browning therein. When a fully devel- would reduce LB development on oped pit is sliced in half, a cavity is fruit in storage. Hydrophilic and lip- Materials and methods present commencing several cell layers ophilic edible films and coatings have Trials were conducted over two beneath the liypodermis (Fig. 2). been shown to alter food moisture crop seasons in Washington State and In severe cases, pits max' overlap and content (1)ebeaufort et al., 1998; one in Chile, in commercial orchards appear coalesced. Generall y, there is Hagenmaier and Shaw, 1990; Kester that had had a history of LB for little corking in the cortex beneath and Fennema, 1989; Morillon et al., several years. In addition to an un- the pit (Fig. 2C). 2002; Quezada-Gallo et al., 2000). treated control, treatments included October-December 2008 18(4) 691 [I TECHNOLOGY AND PRODUCT REPORTS the following three products man- subsequent trials was collected about (Svstat Software, San Jose, CA). Nor- uflhc tu rcd by Pace International 7 d after the last application, which mally distributed data were subjected (Seattle, WA): 1) 2.5% EpiShield I SI preceded commercial harvest b y 1 to to analysis of variance and means were a concentrated emulsifiable mixture 2 d. Seventy apples were collected separated using luke y's Studentized of plant extracts and vegetable esters; from each replication and were trans- range test ( uso). Data not normally 2) 1.5% PrimaFresh' 50-V, an emul- ported to the laboratory, of which 60 distributed [mean LB incidence (%), sifiable concentrate of blended veg- were placed on fiber tra ys in card- mean LB severity (pits/cm 2 )] were etable oils; and 3) 5% Natural board boxes and kept in RA storage at subjected to the Kruskal-Wallis test. Shine rM 9000, an emulsifiable con- -1 °C for poststorage evaluation. At Differences among treatment means centrate of carnauba wax. None of the 0, 90, and 180 d at —1 °C plus 24 h at were assessed at I'!!^- 0.05. orchards used in these experiments 23 °C, 10 fruit from each replication FRUIT SURFACE EXAMINATION had overtree irrigation or cooling, were evaluated for fruit quality.