HortFACT - Shrivel in Braeburn

HortFACT - Shrivel in Braeburn

An Introduction to the Disorder Doug Burmeister - HortResearch, Mt Albert Research Centre

What is it ?

Shrivel (or wilt) is a disorder caused by a greater-than-normal water loss in coolstorage which gives the fruit a dry, wrinkled appearance.

What does it look like ?

Shrivelling of the skin can be very slight or so severe that the whole fruit is affected. Shrivel generally occurs on the green or less blushed side of the fruit. It is commonly found around the calyx depression or stem cavity.

What conditions are needed ?

Excessive water (weight) loss in the fruit after harvest can cause susceptible fruit to shrivel. The level of shrivel increases when cooling is delayed following harvest.

Shrivel can occur in fruit from any region or harvest. However, late harvest fruit appears to be more susceptible to shrivel. Fruit from some regions are more prone to shrivel than others. For example in the 1995/96 season, shrivel was more common in Braeburn from Waikato and Auckland. There appears to be a large variation in susceptibility to shrivel between different growers and orchards within a region.

Anecdotal observations suggest that fruit prone to shrivel come from older, closely spaced orchards that have dense canopies. Fruit from the inner, less exposed, parts of the tree appear more likely to develop shrivel because these fruit may not have developed the surface waxes that would prevent water loss. Trees with heavy crop loads are more likely to produce this shaded, inner-tree fruit.

Shrivel is more common in smaller fruit than larger fruit because small fruit lose more moisture due to a greater area of exposed surface per unit volume.

Where is it found ?

In the 1995/96 season, the worst incidence of shrivel occurred in fruit from the Waikato, Bay of Plenty and Auckland regions. Braeburn from other districts, including Nelson and Hawke’s Bay, can also show this disorder.

Why is it a problem ?

It is difficult to predict whether Braeburn fruit are susceptible to shrivel or not, therefore it is difficult to control this disorder before the fruit are packed and coolstored. Lines of badly shrivelled fruit are often not detected until they show up in offshore markets. At this stage the fruit usually has to be sorted and dumped.

What are the current controls ?

The best prevention at this stage appears to be the proper cooling of fruit and better temperature management of coolstores to avoid excessive water loss. Monitoring of weight loss would be an effective means of determining lines of fruit which may have potential shrivel problems.

Late harvested, poorly coloured fruit are most likely to develop shrivel and orchard practices can be employed to avoid this.

Polyliners in the cartons may be effective in controlling shrivel, even if applied late in the storage period. Polyliners could be considered for late-harvested fruit.

Written and submitted by Helen Percy for HortNET

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