Facebook
X (Twitter)
Reddit
Pinterest
Tumblr
LinkedInPosts Tagged: almond
Winter atmospheric rivers gave pathogens, diseases path to infect crops
Outbreaks similar to El Niño-influenced issues of the 1990s
The wave of atmospheric rivers that swept across the state this winter has created the right conditions for plant pathogens that haven't been seen for decades in California. University of California, Davis, plant pathologist Florent “Flo” Trouillas is getting more calls from growers and farm advisors concerned about potential crop damage.
“Generally, whenever you have rain events, you're going to have problems,” said Trouillas, a Cooperative Extension specialist who is based at the Kearney Agricultural Research and Extension Center in Parlier. “In wet years we get really busy because most pathogens need and like water.”
Trouillas is like a disease detective. He splits his time between the field and the lab, working to diagnose pathogens, diseases and other ailments that strike fruit and nut crops such as almonds, cherries, olives and pistachios.
On a recent visit to an almond orchard near Fresno, Trouillas joined Mae Culumber, a nut crops farm advisor for UC Cooperative Extension Fresno County. A few weeks earlier, the two had walked the orchard, taking note of the base of some trees that had gumming — a thick, jelly-looking substance indicating a pathogen had taken hold.
“A lot of what Florent is doing is trying to assess patterns on a landscape,” Culumber said. “Sometimes things may look like they are one thing, but it could be another problem.”
When the two returned weeks later, the amber-colored gumming had moved into the canopy, looking like gumballs stuck to branches, some of which were already dead. “It's getting out of control from before,” Trouillas says. “This branch was killed. This is widespread.”
From the field to the lab
Lab testing confirmed what Trouillas believed was the culprit: Phytophthora syringae, a pathogen that can affect almond crops but is rarely seen in California. If it is found, generally the site of infection are wounds caused by pruning, but that is not the case here, where the infection began in the canopy at twigs, or small branches.
It is a threat to a key crop, which according to the California Department of Food and Agriculture, generates $5 billion annually. The last time Phytophthora syringae hit California was in the 1990s after a series of El Niño-influenced storms. Trouillas, who has a photographic memory, remembered reading about it in an old manual.
“It's rare for California and one that we see mostly following atmospheric rivers,” he says.
“The disease will only happen following these extremely wet winters.”
Phytophthora is soilborne, mostly found in tree roots, and doesn't generally spread up into branches. But the intense storms created the right conditions for the pathogen to “swim” up trunks as winds blew spores into the air and rain dropped them back down into the canopy, Trouillas said.
Some of the trees in this orchard will die; others can be saved by pruning infected branches and applying a recommended fungicide, he said.
Identification, diagnosis, education
Trouillas is one of more than 50 Cooperative Extension specialists at UC Davis and each is charged with identifying problems and developing solutions for those issues in support of agriculture, the ecosystem and communities throughout the state.
In his role, Trouillas focuses not only on pathology and research but also on educating growers, nursery staff, pest control advisers and others in agriculture about ways to manage potential threats and how to prevent crop damage.
“His role is very crucial,” said Mohammad Yaghmour, an orchard systems advisor for UC Cooperative Extension Kern County. “He's not only on this mission to educate growers but he's also a source of education for us.”
Trouillas typically conducts one or two site visits a week, usually after a farm advisor reaches out about a problem they can't solve on their own.
“This allows us to be at the forefront of disease detections in California,” he said.
He likens these visits to house calls a doctor would make, only to fields instead. And one of those calls recently took him to a cherry orchard in Lodi.
“These guys help me quite a bit,” said Andrew Vignolo, a pest control adviser with Wilbur-Ellis who asked for a consult. “I bug them a lot.”
The visit starts like any consult in a doctor's office, only the questions come fast as they walk around the Lodi orchard where branches are dying, there is gumming and the trees appear stressed. Some look to be sunburned from exposure. Old pruning wounds show cankers, indicating that past disease treatments didn't get rid of whatever was affecting the trees.
Trouillas asks about the cultivar of the trees because some varieties are more susceptible to pests or diseases. He focuses on stress because that opens the door to disease.
Do they prune in the dormant winter months or in summer when pathogens are more prevalent? Does the soil get tested? How old are the trees? What about nutrition?
“I'm trying to figure out how they got infected so bad,” Trouillas said, walking the orchard. “Bacterial canker is a very mysterious disease.”
He thinks it might be a bacterial canker disease and shaves some bark to take to the lab for testing. He wants to come back next winter to take some samples to see where the pathogen is overwintering.
“We'll know in a few weeks if we have a fighting chance,” Vignolo said.
Be it Lodi, Fresno or elsewhere in the state, Trouillas focuses on local conditions. But what is learned in one field can be passed on to others, providing early warnings or advice for those in similar situations. “All these efforts at collaboration, from the field, to the lab, going through research projects, there's only one goal here — to help the farmers of California.”
UC releases a new cost study for growing almonds
UC Agricultural Issues Center has released a new study on the cost and returns of establishing an orchard and producing almonds in the southern San Joaquin Valley.
The cost analysis is based on a hypothetical farm operation of a well-managed orchard, using practices common to the region. Growers, UC ANR Cooperative Extension farm advisors and other agricultural associates provided input and reviewed the methods and findings of the study.
The study estimates the costs for growing almonds in the southern San Joaquin Valley using double-line drip irrigation. This multi-year study estimates costs from the previous crop, including orchard removal, through orchard establishment and the production years.
The economic life of the orchard used in this cost analysis is 23 years. The authors describe the assumptions used to identify current costs for the almond crop, material inputs, cash and non-cash overhead. A ranging analysis table shows net returns over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.
The new study, “Sample Costs to Establish an Orchard and Produce Almonds in the San Joaquin Valley – South- 2016” is the final almond cost-and-returns study in a series of four studies covering three different regions of California published in 2016. The other three studies on almond production include a study on almonds grown in the Sacramento Valley and two studies on almonds grown in the northern San Joaquin Valley. The northern San Joaquin Valley studies use conventional and organic production methods.
Free copies of this study and other sample cost of production studies for many commodities are available online. To download the cost studies, visit the UC Agricultural Issues Center Cost Studies website at http://coststudies.ucdavis.edu.
The cost and returns program is funded by the UC Agricultural Issues Center, which is part of UC Division of Agriculture and Natural Resources and the UC Davis Department of Agricultural and Resource Economics.
For additional information or an explanation of the calculations used in the studies, contact Christine Gutierrez through the Agricultural Issues Center at (530) 752-1520 or cagut@ucdavis.edu.
The enigma of almond pronunciation explained
As a general rule, farmers in the northern part of the state say “am-end” and farmers in southern areas say “almond.” In a quest for an explanation, Romero spoke to numerous farmers and ag industry professionals who all told a version of the same joke. For his story, he quoted UC Cooperative Extension farm advisor David Doll, who he called the "go-to guy" for all things almond in California.
“Farmers will often tell you, you call it an almond on the tree and an am-end on the ground because you shake the l out of it,” Doll told him.
But in terms of the true rational, Doll couldn't provide a definitive answer.
"People who refer to it as am-end tend to be longer-term farmers, so they've been farming for multiple generations,” Doll said.
A UC Davis plant breeder was able to offer a plausible explanation.
When almonds were first introduced by Spanish missionaries, almendras (pronounced with the l) did not succeed. Later immigrants from France and Portugal, who pronounced the nut amandola and amande respectively, brought the crop to Central California.
"Somewhere along the line the use of am-end stuck in Northern California, while the Spanish-inspired noun grew popular elsewhere," Romero reported.
