An airborne fungus from Europe, ganoderma adspersum, has been killing almond trees in the San Jaoquin Valley since it was discovered in the area five years ago, reported John Cox in the Bakersfield Californian.
The fungus rots wood from the inside out, usually weakening the trunk at ground level.
Three kinds of ganoderma fungus infections were identified recently in California almond orchards; University of California researchers say 94 percent of the cases were of the adspersum variety.
"We are seeing those trees collapsing at 11, 12, 15 years old,” said UC Cooperative Extension orchard systems advisor Mohammad Yaghmour. The infections have results in the removal of orchards at less than half their typical 20- to 25-year life span.
Spraying for the fungal disease is ineffective. Yaghmour believes that in time researchers will identify a root stock that is resistant to the fungus.