The Year of the Fungus

One of the secrets to the success of organic agriculture in California is something that non-farmers often assume is a liability:  the lack of rainfall in our state.
Yes, water is the source of life for everything on earth, including food crops.  But most of the food you and I eat everyday does not enjoy being rained on, during at least part of its life.  Humidity encourages fungi, including nearly all the fungi that live on fruits, vegetables, and nuts.
When a fungus damages a crop plant, it’s considered a pathogen.  There are fungal pathogens that infect leaves and other above-ground parts of plants, as well as those that infect the roots and stems.
Most years, California’s growing season is defined by an abundance of sunshine and a near-total absence of rain.  This provides a relatively hostile environment for most fungal pathogens.  The few big exceptions are those fungi that have adapted to the dry summer, such as the powdery mildew that infects grapevines.
Putting this into perspective:  it is almost impossible to grow almonds anywhere else in the United States other than California, simply due to their need for dry conditions for most of the growing season.
For organic growers, California’s weather is even more important.  There are very few effective organically-approved fungicides for some of the most devastating diseases of certain crops, including peaches and tomatoes.
Peach trees don’t mind rain when they are dormant.  But extensive rain during flowering and after the trees have leafed out allows several different fungi to run rampant.  One of these:  peach leaf curl, damages the foliage and can kill whole branches or even whole trees.  Another, brown rot, causes ripening fruit to rot and fall off the tree just before harvest.  Neither can be effectively controlled organically during extended periods of rain.  Humid, rainy Georgia may be famous for its peaches, but growing the fruit organically there is next to impossible.
Rain on full-size tomato plants causes several different diseases (some are bacteria-based, others fungal).  But heavy moisture falling on ripening fruit is even more destructive, causing cracking and mold that makes the tomatoes completely unmarketable.  In areas where it rains in the summer, it is extremely risky to grow outdoor tomatoes organically.  Greenhouses are the only safe option.
These are just two examples of numerous food crops that are highly susceptible to moisture-loving fungi.  Other obvious ones:  berries, cherries, grapes and melons.  But maybe you wouldn’t guess that wheat, beans and even lettuce can’t handle excessive moisture.
2017 has been a challenging year for all farmers in California thanks to the record-busting rains, but even more so to organic growers.  We are still dealing with the aftermath of too much rain, and likely will continue to see affects as the season unfolds.
Thanks for your support,



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