The fires have been raging out of control for the past four days, aggravated by strong winds, and have prompted the President to declare seven counties in the state as disaster areas.
Agriculture officials say it is too early to determine the extent of crop damage, as they will need several days to asses the losses once the fires and winds have died down.
However, initial estimates by commodity organizations suggest that there have been losses to avocado and citrus groves, plant nurseries, winegrape vineyards, egg ranches and other types of farms.
According to the California Farm Bureau Federation, avocados have been affected by both wind and fire.
Marketers have estimated that at least 10 percent of the state's overall crop will be lost.
However, the Federation said that impact on prices and supplies will be moderated by the availability of avocados from other growing regions.
"Emergency officials estimate as much as one third of the state's acreage stood in the path of wildfires.
The commission will survey farmers to gather updated information about losses, but the combination of wind and fire causes serious concerns," it said yesterday.
Farmers also report damage in lemon groves, although there are no estimates as yet as to how much of the crop has been affected.
There is also concern about damage to vineyards, which could affect future supplies of wine grapes.
This season's crop has not been affected as most winegrapes have already been harvested.
There are also reports of pumpkins being damaged by dust and wind, and strawberries being in danger due to the hot, dry atmosphere.
Chickens, dairy cattle and beef cattle are also kept in the affected areas, and fires have so far significantly disrupted the daily operations of ranches by causing damage to buildings and preventing timely transportation.
The most extensive farm-related damage is thought to have occurred in San Diego County, a key agricultural region that leads California production of avocados, flowers and nursery products.
"We've had a lot of destruction to vineyards, cattle ranches, poultry ranches, nurseries, avocados and citrus fruit.
All those crops are produced in the footprint of the burned areas," said San Diego County Farm Bureau Executive Director Eric Larson.
According to reports, farmers in other regions of the state continue working to protect their crops from fire as best they can.
"Right now, we're running drip lines and operating water tank trucks to keep the perimeters of our ranches wet," said Ventura County avocado and lemon farmer David Schwabauer.