A growing sense of normalcy is generating sighs of relief for citrus grower Jerry Driedger this spring.
“Right now we're setting our 2008-2009 lemon crop,” said Driedger, manager of farming-harvesting operations for the Marlin Ranching Company, Yuma, Ariz. “Overall it looks like the crop will be at least a normal crop, barring any unforeseen weather patterns.”
Western citrus growers will never forget the arctic blast in January 2007 that deeply chilled citrus groves from Orange Cove, Calif. to Eloy, Ariz. Seventy percent (18,000 acres) of Arizona's 23,000 acres of citrus are grown in Yuma County where temperatures dropped below 20 degrees over several consecutive nights. About three-quarters of Yuma's citrus crop are winter lemons harvested from September to early February.
“The lemons on the outer fringe of the desert were the most severely affected,” said Driedger, a third-generation grower and chairman of the Arizona Citrus Research Council. “The interior areas had less damage.”
The good news was the freeze occurred toward the end of harvest. Previous cold snaps in the upper 20-degree range had hardened off the trees helping to minimize more severe damage when even colder temperatures arrived, Driedger said.
“We lost some of our Navels and Minneolas in central Arizona from the freeze, while the Minneolas in Yuma made it through the freeze just fine,” Driedger said. Navels and Minneola yields were average last year.
The freeze reduced Driedger's lemon yields 40 percent to 45 percent. Yields could still be light this year as a result of the freeze.
Marlin Ranching Company is a 2,500-acre citrus and alfalfa operation owned by William Chaney, Sun City, Ariz., a member of the Sunkist board of directors. Marlin's citrus includes lemons, Minneolas, Navels, Valencias, and tangerines.
In addition to 1,000 citrus acres in Yuma, the company has about 1,000 citrus acres located north of Dateland, Ariz. (Yuma County). Eloy and Maricopa, located in central Arizona, are the sites of 400 citrus acres. The remaining 100 acres is alfalfa.
Glenn Wright, citrus specialist, University of Arizona (UA), concurs this year should be a good citrus-making one in Arizona.
“The majority of the lemon trees in Yuma this spring had a tremendous bloom that suggests most of the damage from the 2007 freeze has been repaired,” stated Wright.
“Some of the Navels and Minneolas frankly weren't damaged much by the freeze and came back with a bloom last year that created a good Minneola crop. That helped growers partially offset their lemon losses.”
Wright is based at the UA's Yuma Agriculture Center in Somerton, Ariz., located two miles from Driedger's operation.
Yuma's success in lemons is linked to its niche market, Wright said. When Mexico and Chile's lemon supply slows down in September and October, lemon growers in Arizona and California's low desert enter the market with large fruit from late September to November. Lemon harvests in Oxnard and California's Central Valley kick into high gear later.
“The money in lemons in Arizona is in the early to mid-season crop that's large fruit,” Wright explained.
Yuma is an ideal location for growing lemons, not only for the niche factor, but also for the area's abundant sunshine, 92 percent sandy soil that's perfect for lemon production, and the ability to grow lemons during the winter. Winter temperatures generally are not as cold as those in California and central Arizona.
The last comparable freeze to severely chill Yuma citrus groves occurred almost two decades ago in December 1978 which wiped out Yuma's citrus crop. The freeze occurred a month earlier than the 2007 freeze, which meant more fruit on the tree was susceptible to damage.
Turning to this year, Driedger said the Navel crop is setting now and could produce an average crop. Minneolas will set fruit soon with a normal crop expected.
In the short term Wright believes Yuma's citrus acreage will remain fairly steady in the 18,000-acre range. Acreage in the 1970s totaled about 30,000 acres.
In central Arizona, Driedger predicts citrus production will become almost non-existent in the next 5-10 years due to urban encroachment. The Marlin's citrus ground there is leased from developers.
“The only ones who have planted any citrus are the Gila River Indians. They will probably be the last man standing. The Fort McDowell Tribe in Scottsdale, Ariz. also has citrus,” Driedger said.
Currently about 60 percent of Arizona's citrus crop is in lemons and 20 percent is in Minneola tangelos. Navels, tangerines, Orlando tangelos, and grapefruit make up the balance, Wright said. While California growers are having excellent results with the new tango tangerine, the variety is not yet grown in Yuma.
Lemon trees on the Marlin operation are planted 24 feet by 18 feet apart allowing about 100 trees per acre. Navels in central Arizona are planted 22 feet by 22 feet apart while Minneola spacing is 24 feet by 18 feet.
The lemon rootstock generally used by Driedger includes citrus macrophylla and citrus volkameriana using the Limoneira 8A Lisbon as the scion. Water management includes micro sprinklers and flood irrigation in Yuma, micro sprinklers in Dateland, and flood in central Arizona. Irrigated water at the Yuma operation costs $9 per acre-foot compared to $44-48 per acre-foot in central Arizona.
The primary pest on the ranch is citrus thrips controlled with the insecticide Success. “It's the best product and the easiest on the bees,” Driedger said. Citrus red mites and citrus flat mites occasionally flare up, but have been non-existent so far this year. For mite troubles, the miticide Dicofol provides good control. Woolly whitefly and mealybug can also cause problems.
Wright said three species of root rot continue to challenge Arizona citrus growers — Coniophora eremophila, Antrodia sinuosa, and Nodulisporium sp. All three produce air-borne spores that can land in the cracks of citrus branches, primarily in lemons. The cellulose and hemicellulose create weak wood which can snap in heavy wind or under a heavy fruit load. Antrodia is much worse than Coniophora in Arizona.
“If the diseased limbs aren't removed, the tree will be lost.” Since no chemical control is available, Wright advises growers to remove infected branches with a chainsaw. Nodulisporium attacks primarily younger lemon trees. Other diseases include phytophthora and Fusarium root rot.
The honey bee controversy involving mandarin growers in California is not a problem in Arizona, Wright said. The issue facing California citrus growers is bees used to pollinate a variety of crops, including almonds, also cross-pollinate mandarins — resulting in seeds in genetically seedless varieties.
Arizona is home to 50-100 citrus growers, three-fourths of those in Yuma. The five citrus packinghouses in the state include Mesa Citrus Growers, Mesa, Ariz. and four in Yuma - Associated Citrus Packers Inc., Marlin Packing Company, Mission Citrus, and Yuma Mesa Fruit Growers Association.
Driedger said the two largest challenges facing the Arizona citrus industry are crop marketing and skyrocketing input costs. Available farm labor is always a concern but Driedger isn't affected as much as some other growers. “The advantage I have is my employees all work full-time. Between citrus and alfalfa, the operation runs the entire year,” Driedger said. “My labor force is not young, but it's stable. My citrus truck drivers are doing my hay work this time of year.” He employs 20-plus workers on the Yuma operation.
Growers in 2007 had difficulty filling harvest crews, but the smaller lemon crop reduced the severity of the problem. “This year I think it will be a much bigger issue. There are some areas where it's not an issue since H2A workers are utilized. The amount of available labor overall is down,” Wright said.
In addition to his rootstock research, Wright also conducts variety trials plus orchard floor management focusing on cultivator and herbicide use for weed control on the grove floor.
Other research has focused on pre-harvest efforts to reduce the impact of fungi attacking fruit in the box. Separate trials with micronutrient and nitrogen foliar sprays showed little benefit. “We're now looking at the fundamental question of how much nitrogen do lemon trees require on our soil.”
Wright's research efforts are Arizona and California based. He's conducting long-term research trials in Bard, Calif. (Imperial County), and recently kicked-off variety and rootstock studies at the Coachella Valley Agricultural Research Center, Thermal, Calif. (Riverside County). Wright's research currently spans 50-60 acres.