May 5, 2017 CapitalPress.com Subscribe to our weekly California email newsletter at CapitalPress.com/newsletters 11 California Shorter, ‘ladderless’ peach, nectarine orchards taking off By TIM HEARDEN Capital Press PARLIER, Calif. — As la- bor shortages intensify, grow- ers in California are switching to shorter peach and nectarine trees to eliminate the need for ladders. University of California scientists have developed “semi-dwarfing” rootstocks in various densities to create “ladderless” orchards, en- abling laborers to save time by picking from the ground instead of having to move and position ladders during har- vest. Growers have planted about 1,000 acres of the new rootstocks in the past three years, said Kevin Day, a UC Cooperative Extension farm adviser in Tulare County. Tim Hearden/Capital Press University of California Cooperative Extension pomology adviser Kevin Day stands in a “ladderless” peach orchard at the UC’s Ke- arney Agricultural Research and Extension Center in Parlier, Calif. He said growers have planted about 1,000 acres of the labor-sav- ing orchards in the last three years. “They’re being planted by small growers and large grow- ers,” Day said. “They just real- ly like this concept.” Day worked with UC-Da- vis plant physiology professor Ted DeJong in developing the rootstocks, using a four-acre plot at the Kearney Agricul- tural Research and Extension Center in Parlier. Their mis- sion was to test whether short- er peach and nectarine trees could reduce labor and insur- ance costs without sacrificing fruit quality and yield. Day said he’s seen la- bor cost savings of between 35 and 40 percent in tests of semi-dwarfing rootstocks so far. Moreover, the use of lad- ders in conventional orchards is why peach and nectarine growers pay about 40 percent more for workers’ compensa- tion insurance than growers who work with shorter crops such as grapes, the UC has ex- plained. “Also, what people don’t realize is it takes skill to posi- tion a ladder,” Day said, noting a worker needs to be able to pick as much fruit as possible from one spot. “From a sociological per- spective, as labor becomes more scarce, we’re seeing more and more women in crews, and ladders are heavy,” he said. “Women can pick just as fast as men, but moving the ladder takes its toll.” Conventional peach and nectarine trees grow to about 13 feet tall, requiring the lad- ders to harvest the fruit. La- borers spend about half their time setting up, climbing and moving the ladders. Developed by breeders at UC-Davis, the new rootstocks produce trees that grow to 7 or 8 feet tall. The trial at Kearney is part of a larger experiment on best practices for the fruit trees. The researchers have been compar- ing yields from a conventional orchard with those of shorter trees that have been minimally pruned, made use of pressure chambers to determine water needs and been treated with compost and nitrogen sprays to minimize nutrient leaching into groundwater. The scientists found the shorter trees to be more pro- ductive, as their fruit quality overall is equivalent to that of the top half of larger trees, while lower fruit in conven- tional trees tends to be light- starved and of poorer quality, Day said. Day expects more of the shorter trees to be put in as growers change out their or- chards. “Change takes time,” he said. HLB infections in commercial Calif. citrus inevitable, researcher says By TIM HEARDEN Capital Press PARLIER, Calif. — A cit- rus pest researcher believes huanglongbing infections in California’s commercial cit- rus orchards are inevitable, and she believes they’ll force significant changes in the in- dustry in the next decade. Entomology specialist Beth Grafton-Cardwell, direc- tor of the University of Cali- fornia’s Lindcove Research and Extension Center in Ex- eter, says she anticipates “lots of citrus removal” in coming years as trees start dying. “I think this is going to radically affect where and how we grow citrus,” Graf- ton-Cardwell said, adding the disease may cause a shift away from navels and toward more resistant Mandarin or- ange trees. Growers may have to ac- cept shorter lifespans of trees, too, she said. While the av- erage navel tree can live 80 years, growers in China ex- pect their trees to live an aver- age of 15 years, she said. “This disease is hard to control,” she said. “Once it gets going, it’s going to change the landscape in Cal- ifornia.” Grafton-Cardwell said part of her job is to help grow- ers determine how best to Citrus Pest & Disease Prevention Program Tim Hearden/Capital Press University of California citrus entomologist Beth Graf- ton-Cardwell works in a lab at the UC’s Kearney Agricultural Research and Extension Cen- ter in Parlier, Calif. She said it is inevitable that huanglongbing will find its way into commercial citrus trees in California. respond to the Asian citrus psyllid, which can carry huan- glongbing, also known as cit- rus greening. First discovered in the United States in 2005, huan- glongbing has devastated the citrus industry in Florida, Georgia, Louisiana, South Carolina and Texas, causing an average loss of 7,513 jobs per year and costing growers nearly $3 billion in revenue, the University of Florida es- timates. Huanglongbing has caused Huanglongbing, also known as citrus greening, makes the fruit unusable. a 75 percent decline in Flori- da’s $9 billion citrus industry and has led to full or partial psyllid quarantines in 15 states and territories, includ- ing California. The disease has yet to be found in any of California’s commercial groves, but it has killed 54 residential citrus trees in Southern California, prompting the state to first impose and then strengthen a quarantine that now covers about one-third of California. “Everything we can do to slow that spread will buy time for the researchers,” Graf- ton-Cardwell said. “We’re hoping that Florida comes up with a cure because they have the disease and they’re study- ing it.” The problem is that sam- 18-2-#18 pling methods “are not as ef- ficient as they could be,” so infections could occur in trees long before they’re detected, she said. In the meantime, the psyllid is “very effective” at moving the disease, she said. “HLB has a long latent period,” said Ali Pourreza, a UC Cooperative Extension agricultural engineering ad- viser. “Symptoms may show up in a month, or it could be a year. For good management, we need to detect it early. An infected tree is the source of bacteria that can infect an en- tire orchard.” Researchers are looking for ways to detect the dis- ease in trees before symp- toms appear, including by training dogs to identify in- fected trees by differences in odor, Grafton-Cardwell said. Pourreza is working on a sensor that could detect huan- glongbing early. He said he envisions a tool that would be inexpensive for growers — perhaps even a smart phone application. The USDA has spent more than $400 million since 2009 to address huanglongbing. California’s citrus indus- try has devoted $15 million toward HLB research and education, including $8 mil- lion from the grower-funded California Citrus Research Foundation to construct a biosecurity Level 3 lab near UC-Riverside that should be operational this fall. Among the many research efforts, the USDA’s Animal and Plant Health Inspection Service is taking comments through May 10 as it prepares an environmental impact statement on planned field tri- als of a genetically engineered virus that could make trees re- sistant to huanglongbing. Grafton-Cardwell urges growers to be proactive in us- ing best practices to prevent the spread of the psyllid, and she tries to remain optimistic. She notes that citrus crops in the San Joaquin Valley may have a better chance of sur- vival than on the coast, be- cause huanglongbing is sensi- tive to extreme heat and cold. But she knows the industry is going to change, she said. “It makes me sad every day when I drive into Lind- cove and see how beautiful the trees are,” she said. 18-2/#7