Just in time for the holidays, this signature crop is like a slice of California sunshine. And so far this season, there's plenty to smile about.

Oranges – America's original health food – are rolling into packing houses and onto market. And in California, they're meeting new standards for sweetness.

That's pleasant news for both growers and consumers.

"We're off to a good start," said Bob Blakely, director of industrial relations for the California Citrus Mutual. "(The expected harvest) is up 6 to 7 percent over last year. The fruit is eating outstanding. We're really pleased."

Based in Exeter in the heart of the orange belt, the California Citrus Mutual represents about 2,200 growers, mostly in the Central Valley. Three counties – Tulare, King and Fresno – account for 97 percent of the crop; Tulare alone grows one-third of the state's navel oranges.

(Although Citrus Heights and Orangevale credit their names to this crop, local groves were wiped out by hard freezes decades ago and mostly replaced by development.)

The USDA forecasts the California orange crop to hit 93 million cartons; of that, 90 million cartons will be navels from the Central Valley. Each carton weighs 37.5 pounds. That adds up to 1,687,500 tons of navels.

"We grow 80 to 85 percent of the fresh (oranges) for the domestic market," Blakely said. "Just about everything we grow is for the fresh market."

While Florida produces juice oranges, California found its niche with the Washington navel. More than 267,000 acres of orchard land is dedicated to navels.

After a January freeze damaged some of the 2011-12 crop, the current crop benefited from near-perfect growing conditions. Oranges need a mix of hot summer days and chilly winter nights to develop their flavor.

"We had excellent growing conditions through summer," Blakely said. "Then, we had cool nights but not extreme weather. The fruit colored up nicely. That's also ideal for making a lot of sugar."

This year, the state's orange growers started using the new "California Standard" to measure maturity.

"The goal is a sweeter orange; that's what consumers want," Blakely said. "The California Standard uses a completely different formula (than previous tests) for determining maturity and when fruit is ready to pick. It's been proven with seven years of research. The result: We'll put out sweeter oranges when they go to market."

Meanwhile, growers are on the alert for Asian citrus psyllid, a serious pest that's been known to transmit the fatal citrus disease huanglongbing, or HLB. There's no known cure for HLB, responsible for destroying vast citrus orchards in Florida and Brazil. (So far, only one HLB-infected tree has been confirmed in California.)

First spotted in California in 2008, the Asian citrus psyllid – which is about the size of an aphid – has become relatively common in the Los Angeles suburbs, infesting backyard citrus trees. But until this year, none had been found in the Central Valley's commercial groves.

One was trapped last January near Lindsay. Then, two showed up in November elsewhere in Tulare County, bringing an immediate quarantine and restrictions for growers in the county's southeast corner.

"We think the bugs hitchhiked up here from L.A.," Blakely said. "Both groves are close to a major highway. We're pretty confident there's no breeding population, but our industry does not want any outbreak."

Pickers started harvesting in November. New late varieties have helped stretch navel oranges' fresh-picked season into late July.

"In a large crop year like this, we may still be picking in August," Blakely said. "Oranges are an amazing piece of fruit. You can store it on the tree. During winter months, it's like keeping it in the refrigerator."

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