I could only find one reference for this besides this very question:

[DOC] La fertilización nitrogenadaFile Format: Microsoft Word - View as HTML
En muchos casos no se retira a tiempo la fruta rezagada o "pampanitos", lo que alarga el desgaste de la planta. Esta sigue enviando nutrientes y reservas a ...
www.tierraverde.cl/doc/la_fertilizaci�n_nitrogenada.doc -

From that I would say "unpicked fruit".

Compared to an overripe pear, the wine will be reminiscent of wizened fruit and wilted flowers. - A wine, whether young, adult or aged made from over-ripe ...
www.billaud-simon.com/Billaud-Simon Text_when_to_drink_wine... - 45k - Cached - Similar pages

THE SECRET LIFE OF THE APPLE - NI 212 - Simply... A history of the ...But these were wild crab apples, tiny wizened fruit which, in Ancient Britain, came to be known as 'wildings'. They had little in common with the apples we ...



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Note added at 1 hr (2007-12-09 02:21:29 GMT)
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Compared to an overripe pear, the wine will be reminiscent of wizened fruit and wilted flowers. - A wine, whether young, adult or aged made from over-ripe ...
www.billaud-simon.com/Billaud-Simon Text_when_to_drink_wine... - 45k - Cached - Similar pages

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Note added at 1 hr (2007-12-09 02:23:30 GMT)
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arrugado · lined (face); wizened; wrinkled; wrinkly (fabric. arrugando · shrivelling. arrugar · to crease ...... avión rezagado en una formación · straggier ...
romanica.wikia.com/wiki/Dictionario_Hispanico_001 - 523k - Cached - Similar pages

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Note added at 1 hr (2007-12-09 02:25:10 GMT)
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Likewise, wizened fruit is shriveled, old fruit. The word can also imply a shrinking in size. Note: The first syllable is pronounced wiz (not ...
books.google.com/books?isbn=0972743901...

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Note added at 1 hr (2007-12-09 02:29:44 GMT)
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or: shriveled fruit

Avoid: Shriveled fruit, dried stems, soft, leaking flesh, brown discoloration, mold growth, and a generally dull appearance. Because of their normal dark ...
findarticles.com/p/articles/mi_m0813/is_n4_v19/ai_12272993 - 30k - Cached - Similar pages

cuando ya la fruta se pasa de madura

or fruit that is past it, or that has been picked a long time

old fruit and vegetables

some old fruit and veg. may not shrivel, but the point is that they aren't fresh and will have lost vitamins, etc.

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Note added at 16 hrs (2007-12-09 16:55:50 GMT)
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rezagarse verbo reflexivo to linger behind: no os rezaguéis, don't fall behind

http://www.wordreference.com/es/en/translation.asp?spen=reza...

It means probably fruit that isn't fresh anymore (acording to your context, he's advised to eat fresh fruit). Rezagada means "that is late" so it's a bit strange to apply it to fruit but...