Wet Roots

I recently harvested 'GEM' avocados and found that some of the fruit was splitting. The split fruit was just turning from a bright green to one with dark tinges. There were also gobs of snails and slugs on the fruit. I mentioned the cracking fruit to a grower who had been harvesting ‘Hass' fruit and the comment was that their fruit was turning black on the tree and falling. This is way early for ‘Hass' to show this level of maturity.

Several mandarin growers also mention peel breakdown or rind disorder. There can be brown, water-soaked blotches or dark, sunken areas developing on the rind after rainy weather. The fruit matures rapidly, turning orange early. Secondary fungi can then colonize the affected areas. It's more of a problem in northern California where thin-skinned satsumas are grown and there are early rains. But accelerated maturity and fruit/whole plant breakdown can happen on all citrus and many other fruiting plant species.

This is another example of accelerated maturity due to wet roots. The roots need air, like we do, and when they are asphyxiated for even short periods of time, they start signaling the rest of the plant that something is wrong. Prolonged rainy periods or actual ponding conditions will lead to ethylene precursors that start the maturation process – “banana in a bag” effect. This is in spite of many crops being delayed in their maturity because of the cold winter we have had. Drown the roots, and they start responding as if they are choking. They are. In some cases, leaves will droop (epinasty or wilting) and drop, immediately.   And then the fruit may drop right away or then just start rapidly maturing/ripening on the tree. Once this process starts, there's no stopping it. Some growers, seeing fruit drop have gone out to start harvests, but then inadvertently gotten their forklifts stuck in the mud. Rain can have its downsides.

mandarin rind disorder

lemon cold wet exposure

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