The name Phytophthora literally means “plant destroyer” and certain species of the pathogen wreak havoc on almond trees in California.
“Phytophthora root and crown rot are extremely widespread in California,” said Maxwell Norton, retired University of California Cooperative Extension agriculture advisor and one of very few who specializes in tree fruit production. “Phytophthora causes disease in orchards globally. What makes it difficult to work with is, if conditions are just so, tree death can occur quickly, in as little as year with younger trees.”
Sublethal infections are common, too, where a tree simply loses vigor and is less productive.
The organism that causes Phytophthora is commonly found in surface water sources like irrigation district sources and canals, he said. “Everyone goes on the presumption that it’s probably present in their soil some place.”
But by the time it’s detected, it’s often too late and the damage is done.
Based in the San Joaquin Valley south of Sacramento, Norton is a special advisor to Trace Genomics and is highly involved with clients including the company’s contract with Wilbur-Ellis – using Trace Genomics’ pioneering soil DNA technology to get a handle on the prevalence of the soil-borne pathogen in almond trees, and tailor recommendations to apply product more precisely. It’s about producing more with less.
“All of us have the objective of only applying any pesticide where it’s needed and try to avoid unneeded preventative treatments – not only to be economical but to prevent resistance,” he said. “Using Trace Genomics technology can help us know where to look and make more informed decisions.”
Trace Genomics soil testing and diagnostics gives agronomists and growers access to the most comprehensive soil biology and chemistry analysis available, helping them make data-based decisions.
“What we’re trying to do in agriculture is use science to help us make decisions instead of letting fear drive us,” said Norton. “We try to avoid applying a pesticide but may do so simply because we’re afraid of not doing it. The more knowledge we have about the ecosystem in an orchard the more likely we can make scientifically informed decisions about pesticide use. That’s very informative all the way around in terms of sustainability.”
In California almond orchards, “most of soil testing is done to try to detect chemistry problems – salts and toxic ions like chloride and boron,” said Norton. “There are not a lot of diseases we soil sample for. That’s why Trace Genomics technology is exciting.”
Pest management is complex. There’s a wide assortment of diseases and pests both above and below ground that affect California crops – especially nut crops. Rooting them out involves homework, scouting and being a keen observer, said Norton.
In California, if you’re compensated for giving advice about crop input use, like Norton is, you have to be licensed, have a college degree, attend a two-day long set of board exams and complete 40 hours of continuing education every two years. “I think it’s more education than lawyers,” he joked.
But it’s serious business as pest advisors are extensively trained to use science and an assortment of tools to gather huge amounts of information.
“Trace Genomics technology fits right in,” he said. “It appears to be a breakthrough that will help us detect diseases in the field that may or may not already be a threat. Positive tests will prompt us to look much closer for disease occurrence in the field and identify management practices to mitigate risk.”