By Dan Whitcomb
LOS ANGELES (Reuters) - The wildfire that roared through the orchards of California's Ventura County destroyed much of the region's avocado crop not just with flames, but also with fierce Santa Ana winds and a thick blanket of ash.
With the so-called Thomas Fire just 10 percent contained by Friday afternoon, after blackening more than 132,000 acres across Ventura County and destroying some 400 homes and other structures, it is too soon to know the extent of the damage to the upcoming avocado harvest.
But experts say even the mostly family-owned orchards spared by the epic conflagration may have suffered devastating losses to their crops from the hot, dry Santa Ana winds that blow out of the California desert, knocking avocadoes from the trees with gusts up to 80 miles per hour.
The fruit cannot be sold for human consumption once it is on the ground due to food safety regulations.
"A lot of that fruit everybody was looking forward to harvesting next year is laying on the ground," said John Krist, chief executive of the Ventura County Farm Bureau.
Avocados are the rare produce trees planted in hillside groves because of their shallow roots, said Ben Faber, a University of California farm advisor in Ventura. The fruit, typically harvested in February or March, is full-sized and a heavy fruit by December, held by a long stem.
Those factors make avocados, already growing away from their natural environment in Central and South America, more vulnerable to the whipping winds than the lemon orchards dotting the flatlands of Ventura, Faber said.
Lemons are also a lighter fruit with a shorter, sturdier stem. Ventura County is California's largest growing region for both lemons and avocados. The state produces about 90 percent of the nation's avocado crop and 80 percent of its lemons.
Some avocado trees that do not appear to have been scorched could also reveal damage later, collapsing from internal heat damage. Fruit that did not burn or get blown off the branches may be sunburned by the loss of canopy.
Both lemon and avocado crops are also likely to suffer further from the thick coating of ash left by the Thomas Fire, which interferes with the natural enemy insects that hunt the pests feeding on the fruit trees. Those enemy insects are known to growers as "bio-controls."
"When you get all this ash, they can't do their jobs," Faber said of the enemy insects. "That's going to cause a disruption to the bio controls that's going to go on for a year or more. So the impact of the fires is not all immediate."
Unlike grapes at wineries in California's Napa Valley wine-growing region hit by wildfires in October, however, avocados and lemons will not be affected by smoke from the fires due to their thick skins.Experts said at the time that the delicate grapes, if exposed to sustained heavy smoke, could be vulnerable to "smoke taint," which can alter their taste and aroma.
Consumers are not expected to see an impact on avocado prices because Ventura County is only a small piece of the worldwide production chain dominated by Mexico and South America, the farm bureau's Krist said.
Avocado prices have been higher in most U.S. markets during the second half of 2017, according to the Hass Avocado Board, in part due to a poor harvest last year in both the United States and Mexico.
The wildfire news didn't have a major effect on the stock price of the Limoneira Company , the nation's largest avocado grower, as shares closed essentially unchanged on Friday.
(Reporting by Dan Whitcomb; Additional reporting by Lisa Baertlein; Editing by James Dalgleish)