what time of year to pick bartlet pears

Recommendation for Harvest and Storage of Pears

Agdex#:	215/fifty
Publication Appointment:	July 2012
Club#:	12-041
Last Reviewed:	July 2012
History:
Written by:	J. R. DeEll and K. Slingerland

PDF - 2 MB

Table of Contents

• Introduction
• Maturity
• Harvest and Treatment
• Storage
• Summary
• References

Introduction

Pears can be harvested near ripe and sold for immediate consumption for fresh markets. Notwithstanding, about pears grown in Ontario are stored for a period of time and marketed throughout the fall season. Other countries that produce big amounts of pears ofttimes store well-nigh of the production and then market the pears for 6-eight months.

Long-term storage of pears has often been a challenge. Many cold storage facilities in Ontario are outdated and non suitable for long-term storage of pears. Bartlett pear, which has been the number one pear for many years, must be harvested carefully and at the right maturity for long-term storage. Nether Ontario atmospheric condition, storing Bartlett pears for longer than 1-2 months has frequently resulted in a high percent of culls.

Recent cultivar improvements have given Ontario producers the opportunity to modernize the pear manufacture. New storage technologies accept also revived optimism in storing and marketing pears for longer periods of time than in previous years.

Bartlett and Bosc take been the ii main pear cultivars in Ontario for over 50 years, simply plantings have been rapidly failing due to reduced yield and tree mortality. New pears have recently been released from the Agriculture and Agri-Food Canada breeding program at Harrow: Ac Harrow Well-baked™ and Harovin Sundown™. In add-on, the selection HW620 shows expert hope and is under trial. These new pears have the potential to expand the pear industry in Ontario because of their resistance to fire blight, a subversive affliction.

Maturity

Virtually pears accomplish optimum harvest maturity for storage while they are still green and difficult. Therefore, pear maturity is primarily determined past compactness. Some pears destined for immediate auction might exist left on the tree for several days longer, as they soften and begin to turn yellowish.

Fruit firmness testing is currently the master method used to determine pear maturity. Checking firmness involves sampling a number of pears in the orchard. Sample 10 pears for every acre, bold that the cake is uniform. Firmness is measured at two opposite sides on the equator of each pear after removing the peel, using a penetrometer with an viii-mm (5/16-in.) diameter tip (Figure 1).

Figure 1. Measuring pear firmness using a penetrometer.

As firmness decreases, the pear begins to soften and mature. Each cultivar has different compactness characteristics and unlike rates of softening as the pear ripens. For long-term storage, pears are harvested when very firm and less mature, compared to pears destined for immediate consumption.

Soluble solids concentration (SSC, °Brix) is another method of identifying maturity. SSC is affected past several factors, such as crop load, rainfall and temperatures prior to harvest, and location on the tree (exposure to more sunlight on the tree exterior usually causes pears to mature earlier). Generally, a minimum of 10% SSC at harvest is required to obtain the best pear quality.

The starch iodine test can also be used as an alphabetize for pear maturity. For case, Bartlett pears are fix to harvest when 60% of the maximum starch content remains. Withal, this does not appear to be an accurate mensurate for maturity of the new pear cultivars.

Days from bloom to harvest is often used equally a guideline for predicting pear maturation. For example, Bartlett pears in the Niagara region generally flower effectually May 18 and harvest is approximately September 5, which equals 115 days from bloom to harvest.

New methods for measuring pear maturity are currently being evaluated in pear-growing regions. Optical density, measured using a multiple wavelength light transmittance meter, is a method used in California for specific cultivars. A non-subversive DA meter can chop-chop measure chlorophyll content using nigh-infrared spectrometry. However, its success for predicting maturity varies, depending on the cultivar.

Other important factors in determining pear maturity include colour, finish, percentage of blush and ease of separation of the pear from the spur. Estrus units are more often than not not a good indicator of pear maturity.

Bartlett pears are the near predictable and understandable, and standard measurements for firmness take been well established for many years. However, there is a rapid loss of firmness during the harvest window, so it is best to get the pears off the trees quickly earlier they become likewise soft for commercial use. For long-term storage, harvest Bartlett pears effectually 81-85.5 N (xviii-19 lb) pressure level; for short-term storage or firsthand use, harvest at 67.v-76.five N (15-17 lb) pressure level.

Bosc pears typically store well for about 3 months. Harvest pears at around 72-81 N (xvi-eighteen lb) pressure for the all-time storage results. The firmer the pear, the longer it will maintain good quality in storage.

Air-conditioning Harrow Well-baked ripens 2-three days after Bartlett. All the same, the best maturity index however needs to be determined, and it may not be firmness. Harrow Well-baked typically begins to soften earlier in the season than Bartlett but tends to remain firm at 63-72 N (14-16 lb) pressure for a long menses of time. Early-picked pears can be stored for two-iii months, but storage life is reduced with later-picked pears (i.e., <54 Northward (<12 lb)).

Harovin Sundown typically ripens 2-3 weeks later on Bartlett. This is another cultivar for which the best maturity index has still to be determined. This pear typically begins to soften earlier than Bartlett, but tends to remain at 45-63 N (10-14 lb) pressure for a long period of fourth dimension, upwardly until harvest. In some cases, the colour of the pear starts to change from green to yellow, with a pink blush, while staying firm. Flavor is generally good, but at that place tin be some astringency in the skin at harvest.

HW620 tends to ripen 3 or more weeks after Bartlett and within a calendar week after Harovin Sundown. This selection needs more grower treatment and experience to determine optimum maturity indices. HW620 usually begins to soften earlier in the flavour than Bartlett merely then tends to remain at 54-63 Northward (12-14 lb) pressure for a long period of time until harvest. As these large pears mature, they tin can loosen from the spur and drop prematurely. The color tends to remain a "deep" green as the pear matures, while maintaining the same firm pressure level. Soluble solids are slow to rise every bit the pear matures and the harvest date nears.

Harvest and Treatment

There are just five-half-dozen master cultivars of pears in Ontario. The harvest season is from late Baronial to early October. Most pears reach optimum harvest maturity for storage while they are notwithstanding green and difficult. Some of the recently released pear cultivars remain firm on the tree for longer periods of time and can be harvested with less firmness than Bartlett. Some cultivars have fruit that adhere to the spur and are difficult to remove, while others fall off quite easily.

Pears are by and large picked directly into baskets or bags that are gently placed into big bins for storage. The nearly common bins used for harvest accept been wood, and the use of plastic liners has helped reduce skin damage and scuffing. More recently, the industry has been changing to plastic bins to reduce impairment to pears.

Preharvest practices for controlling storage rots are of import for storage and pear quality. In one case the pears are deemed ready for harvest, pick them every bit apace as possible to maintain firmness. If harvesting continues over an extended period, separate loads of pears into long-term and curt-term storage. Pears harvested well-nigh the stop of harvest and with lower firmness tend to be susceptible to more diseases, decay and storage problems.

Mowing tin reduce humidity in the orchard before harvest and reduce fungus populations, thereby reducing infection of the pears earlier harvest. Avoid harvesting during pelting or early morning time dews, and then that pears are dry when placed in the bin, to assist reduce the possibility of infection and disease development.

During harvest, have pickers clothing gloves or cutting sharp fingernails, which can pb to creating punctures and other entry points for decay fungi. Stalk punctures (Figure 2) are very common during harvest, and so accept pickers place pears into the picking basket or bag advisedly. Most decay enters pears through punctures or small cuts. Anything yous tin can do to reduce skin breaks in pears will reduce storage rots. Ensure picking bags or baskets are free of any edges that can cutting pear peel. The later the pear is harvested, the softer information technology is and the more prone to punctures and cuts.

Figure 2. Stem puncture causing storage rot.

Scuffing is acquired when pears are rubbed or pressed against a rough surface (Effigy 3). The damage appears as dark brown or black marks on the skin and increases equally the pear gets softer. To reduce scuffing, utilize bin liners stapled to the outside of the bin. If liners are stapled to the inside, exposed staples are left when the liner is removed, leaving a source of punctures for the adjacent time the bin is filled. Ensure bins are clean, dry out and free of dirt and gravel that could cut or puncture pears. It is also important that tow-motor drivers keep soil and gravel out of bins and off bin track. This debris can cut pear skin and too finish up in the packing firm and storage area where it can contaminate pears.

Figure three. Scuffing (friction marking) in Bartlett.

Pears are sensitive to bruising during harvest and handling. Physical or mechanical harm, such as scuffing, bear upon and pinch bruising, does not e'er evidence up right abroad but tin can develop later in storage. Practice not overfill picking baskets and bins, and have care when pouring the pears into the bins. Remind pickers non to press against the bin with their bags when emptying out the pears.

It is of import to minimize vibration during transport from the field to the packing firm. Grade orchard laneways, minimize the number of moves for full bins and utilise air ride intermission systems whenever possible to avert bruising. Practice not leave baskets and bins in direct sunlight, and absurd pears equally presently as possible for long storage life. Any unnecessary delays in cooling pears have a huge effect on their quality subsequently during storage.

Grading pears in the packing house is another surface area where scuffing and bruising oft occur. Pears moving on conveyer belts oftentimes come in contact with unprotected edges, machinery parts and other pears, which can cause damage. Protect pears during the packing procedure by reducing the number of drops, and cushion the surface area where the pear lands. A drop of 7.half-dozen cm (iii in.) or more onto a hard flat surface damages pears. Use padded ramps, drapes and shallow transitions between belts.

Pears can either be packed a few days after cold storage, when field heat has been removed from the pears in the bin, or stored until they are ready for market place, then graded and shipped to their destination.

Storage

Once harvested, pears begin to undergo the ripening procedure to develop total flavor. It typically only takes a few days to a couple of weeks at room temperature to ripen nearly cultivars. Business firm green pears brainstorm to soften as starch changes to sugar. The skin colour also begins to change from green to yellow. During this ripening period, the respiration rate increases, as does ethylene production. When the bulk of pear product will be marketed over a long period of time, it is important to shop the pears to command ripening processes.

Cooling the pears prior to storage is i of the nigh of import steps to ensure adept fruit quality. The most common method of storing pears in Ontario is by traditional room cooling. The crop is taken from the field to the cold storage in either x.4-L (11-qt) baskets or bins. This is a relatively slow method of cooling pears. Depending on temperatures during harvest, it can ofttimes have 48-72 hours to bring the temperature downward to approximately 1°C. In that location are few controlled atmosphere (CA) storages that are used for long-term pear storage in Ontario. However, CA storage can extend storage life, using atmospheres ranging in 1%-two% oxygen and 0%-ii% carbon dioxide, depending on pear cultivar.

Forced-air cooling is the most mutual method of rapid cooling for pears, peculiarly in areas of big production. This can absurd pears five to eight times faster than traditional room cooling. Hydro-cooling is another effective and rapid method of cooling, but it may increment postharvest decay past spreading pathogens.

Some growers and packers grade and pack out culls before long later on the field temperature has been removed from the bin or basket. The pears are so packed straight into boxes, put dorsum into storage and are now ready for market.

Information technology is important to maintain very high humidity, at least 90%-95%, during the storage period to reduce visible signs of shrivel on the skin. Almost modern commercial storages can maintain adequate relative humidity; however, many older, smaller, on-farm storages designed for brusk-term storage likely cannot maintain such high relative humidity. Humidifiers can add moisture to reduce water loss in the pears. Wooden bins and packaging material naturally gain moisture as well, so it is important to monitor the relative humidity. To reduce water loss from bin absorption, supercede wooden bins with plastic bins. Fogging or misting humid air into the storage room can too increase relative humidity. Wetting the floors is the least constructive method to increase humidity.

The two most common storage rots are blue mould (caused by Penicillium expansum) and gray mould (caused by Botrytis cinerea). These are spread easily through the air in storages, so it is of import to maintain a preharvest orchard spray program and monitor fruit regularly during storage. Handle pears advisedly during and afterward harvest to minimize stem punctures, skin breaks and bruises, which human activity as infection sites for fungi. During storage and transportation, move the bins with minimal jolts and drops. Absurd and refrigerate the pears as speedily equally possible. Each storage room must have adequate refrigeration capacity. Using mod refrigeration facilities and controlled atmospheres reduces storage rot.

Sanitation in the handling and grading area is important. Remove rotted pears from the bounds and property. Modify the h2o used for dipping or drenching ofttimes. Postharvest treatment with fungicides can reduce affliction incidence.

See OMAFRA Publication 360, Guide to Fruit Product, for further information on illness control.

Senescent scald and storage scald are the principal external physiological disorders that develop on pears in storage. Senescent scald develops when pears lose their ability to ripen, after extended storage durations. The pears plow yellow and eventually develop dark brown skin (Figure four). The browning can showtime during storage or correct after the pears are put into room temperature. Reducing the storage period and using all all-time management practices can reduce the chances of senescent scald. Information technology can likewise exist reduced if pears are stored in controlled atmosphere storage.

Figure iv. Senescent scald in Bartlett.

Storage scald (also known as superficial scald) develops during storage, only signs are not visible until pears are moved to warmer temperatures (Figure 5). This is strictly a surface disorder, which causes bronzing of the skin. Storage scald tin can be reduced if pears are stored in low-oxygen storage.

Figure five. Storage (superficial) scald in Sundown.

Cadre breakup is a serious internal disorder, especially in Bartlett (Figure 6). Information technology can only exist detected by cutting into the pear. The pear becomes unmarketable, as the flesh in and around the cadre turns chocolate-brown and soft. Late-harvested pears are normally more susceptible. Pears that tend to soften chop-chop, like Bartlett, are generally prone to this disorder. Maintaining proper temperatures from the time of harvest right through to retail marketing is important for decision-making this disorder.

Effigy vi. Cadre breakup in Bartlett.

A new applied science was recently commercialized for delaying the ripening of apples and pears during storage. SmartFreshTM (1-methylcyclopropene, ane-MCP) inhibits the activeness of ethylene, the natural ripening hormone of pears. It has been shown to inhibit ethylene production, retard respiration rate, delay or preclude softening, and essentially reduce storage disorders in various pear cultivars.

Conclusions from a review on the ripening of European pears indicate that there is nevertheless no clear understanding of the best combination of harvest maturity, SmartFresh concentration, application conditions (temperature and fourth dimension) and storage time afterward SmartFresh treatment to adequately command softening and the development of physiological disorders, while simultaneously allowing the pear to ripen to good quality for marketing. However, work on Ontario pears has shown that an overnight treatment with the Canadian label rate of 300 ppb i-MCP applied 3 days subsequently harvest provides the best residual of reduced disorder development during storage and the ability of Bartlett pears to soften adequately thereafter. In other growing areas, especially on the West Declension, there continues to be a risk of excessive inhibition of ripening when using SmartFresh on European pears.

Bartlett pears are fairly predictable for softening during storage. If harvested at 81-85.5 Northward (18-nineteen lb) pressure, the pears volition easily store for up to iv months at 0.5°C and maintain a pressure effectually 54-58.5 N (12-13 lb). In one case removed from storage and delivered to retail for sale, they quickly soften to around 22.five-31.v Northward (5-vii lb) force per unit area after only a few days at room temperature. The colour of the skin also quickly changes from green to yellow. More disorders develop in pears harvested later (approx. 45-63 N (10-xiv lb) pressure), which limits storage life.

The utilise of SmartFresh can better firmness retention in Bartlett pears later removal from storage. Skin colour also remains greener for a longer period of fourth dimension. Pears treated with SmartFresh tin can be 22.five N (5 lb) firmer than untreated pears after storage. Senescent scald and internal breakdown are substantially reduced by using SmartFresh. Senescent scald has been reduced past 50%-90% with SmartFresh, subsequently iv months of storage at 0°C and 5 days at xviii°C-19°C, compared to untreated pears. Friction marking is also significantly reduced by SmartFresh.

Bosc pears typically shop well for upwardly to 4 months at 0.5°C. Softening of the flesh is not as rapid every bit in Bartlett pears. Although SmartFresh has had variable effects on Bosc, it can filibuster softening, ethylene production, acidity loss and colour change during cold storage plus another fourteen days at room temperature. SmartFresh may also reduce the incidence of storage rots.

AC Harrow Crisp picked early tin can be stored for nigh iv months, but storage life is reduced with later harvest. If kept too long or harvested likewise late (i.e., <54 North (<12 lb)), it will deteriorate internally without external signs. It tends to be decumbent to developing internal cavities (Effigy seven), as desiccation and browning within the flesh, particularly afterward extended storage durations and in late-harvested pears. Harrow Crisp is also susceptible to scald, but it remains unclear whether it is senescent or storage scald (or both).

Figure 7. Internal cavities in Harrow Well-baked.

SmartFresh is very effective at delaying softening of Harrow Crisp pears. Pears harvested at 63-67.5 N (fourteen-15 lb) pressure and treated with SmartFresh stayed firm after ii months at 0.5°C plus 7 days at 21°C, while similar pears only lost ix N (two lb) pressure after iv months at 0.5°C plus vii days shelf-life. In comparison, non-treated pears lost 22.5-36 N (5-8 lb) force per unit area during the same period. Pears treated with SmartFresh and harvested later, at 54-63 N (12-14 lb) pressure, tended to soften more quickly than those from the before harvests. Colour alter to yellow is also delayed by SmartFresh. In contrast to these benign effects, the incidence of internal cavities developing in the mankind can exist increased with SmartFresh.

Harovin Sundown pears harvested early (greenish and around 63-67 North (14-15 lb) pressure) tin be stored for about four months, whereas those harvested later (greenish-yellowish and around 45 Due north (10 lb) pressure) have reduced storage life. Harovin Sundown appears to be susceptible to senescent scald, equally well as an internal watery breakdown of the flesh (Figure 8). Internal cavities and flesh browning accept also been observed occasionally. There are fewer storage disorders in pears harvested around 58.5-67.v Northward (13-15 lb) pressure, suggesting that this is the appropriate harvest maturity for subsequent storage.

Effigy 8. Watery internal breakdown in Sundown.

Treatment with SmartFresh slows softening and ripening of early-harvested Harovin Sundown pears but has fiddling outcome on those harvested belatedly. In riper pears harvested effectually 45 N (x lb) pressure, SmartFresh has no significant effect on the incidence of storage disorders. Slight incidence of internal cavities in the flesh has been observed in some pears treated with SmartFresh.

HW620 is typically very uniform at harvest, with fiddling ethylene production and starch content, and a deep green skin colour. When harvested at 54-63 Due north (12-xiv lb) pressure, it tends to stay firm during storage for nigh 4 months. HW620 appears to exist susceptible to scald, core breakup and internal browning.

SmartFresh treatment prevents softening in HW620 and the skin color modify to yellow during storage at 0.v°C for four months plus 7 days at 21°C. All the same, pears treated with SmartFresh usually brainstorm to soften and plow yellow afterwards 14 days at room temperature. Treated pears often take no scald or internal browning, whereas the non-treated pears have meaning amounts. SmartFresh can also reduce the incidence of friction marker.

Summary

Harvest all pears destined to be stored for whatever duration at the proper maturity, and handle them with intendance during harvest. Cool pears as quickly as possible and store them at the proper temperature (-1°C to 0°C) with loftier humidity (xc%-95%). With SmartFresh, well-nigh pear cultivars volition remain firmer during storage and for longer periods of time after existence removed from storage. In addition, SmartFresh substantially reduces storage disorders.

Harvest Bartlett pears when compactness reaches 81-85.5 N (18-19 lb) pressure level and Bosc at 72-81 N (sixteen-18 lb). The later the pears are harvested and the softer the pear, the more likelihood there is of storage disorders developing. SmartFresh significantly delays softening, ethylene product, acidity loss and colour change, as well equally improving firmness retention and controlling disorder evolution in Bartlett pears after removal from storage.

Harvest Harrow Crisp, Harovin Sundown and HW620 pears at around 58.five-67.v N (xiii-15 lb) pressure. Similar to the dominant cultivars, the later on the pears are harvested and the softer the pear, the more likelihood there is of storage disorders developing. SmartFresh handling causes these pears to remain firmer in storage and stay firmer one time removed from storage, compared to untreated pears or those harvested at a later maturity. SmartFresh reduces most storage disorders, such as senescent scald, internal browning, core breakup and friction marking. However, the incidence of internal cavities developing in the flesh can be increased by the apply of SmartFresh, specially in subsequently-harvested Harrow Well-baked.

Using all best management practices to reduce bruising and fruit injury in the field and during the packing process will help ensure proficient quality pears going into the storage. Maintain proper temperatures and high relative humidity during storage to reduce disorders and diseases, and permit pears to be stored for longer periods of time.

References

• Slingerland, K., and W. MacFadden-Smith. Baronial 2011. Pear Production in Ontario. Ontario Ministry of Agriculture, Nutrient and Rural Affairs. Factsheet Order No. 11-047.
• DeEll, J., and B. Ehsani-Moghaddam. 2011. Timing of Postharvest 1-Methylcyclopropene Treatment Affects Bartlett Pear Quality subsequently Storage. Can. J. Institute Sci. 91: 853-858.
• DeEll, J., and B. Ehsani-Moghaddam. 2010. Storage to Assist Extend the Seasonal Availability of Pears. Report for CanAdvance Project ADV-635.
• DeEll, J., and 1000. Slingerland. 2009. Storage to Assist Extend the Seasonal Availability of Pears. Report for CanAdvance Project ADV-635.
• Mitcham, E.J., and R.B. Elkins. 2007. Pear Product and Handling Manual. University of California Agriculture and Natural Resources. Publication 3483.

This Factsheet was authored past Dr. Jennifer R. DeEll, Fresh Market Quality Program Lead, OMAFRA, Simcoe, and Ken Slingerland, Horticultural Consultant. Information technology was reviewed by Dr. Gale Bozzo, Postharvest Biochemistry and Secondary Metabolism, Department of Plant Agriculture, University of Guelph; Kathryn Carter, Grape and Tender Fruit Specialist, OMAFRA, Vineland; and Colleen Haskins, On-Farm Food Safety Specialist, OMAFRA, Guelph.

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Source: http://www.omafra.gov.on.ca/english/crops/facts/12-041.htm