Fire Blight Outbreak Affects Pear and Apple Trees in Marin County

In Chileno Valley, the trouble is attached to trees. A commercial orchard there has been devastated by fire blight, a bacterial disease that is now showing up widely among apple and pear trees across West Marin.

The outbreak was reported by the Point Reyes Light, which described the disease as unusually prevalent this year. The affected orchard gives the story a hard edge: fire blight is not just a blemish in the canopy when it moves through a commercial planting; it can turn a crop problem into a block-level loss. The Marin County outbreak was reported in early September.

A Warm Year in West Marin

Temperatures in West Marin have contributed to the unusually high incidence. That weather link matters because it puts the disease in the same ledger as irrigation timing, harvest labor and every other decision made under a narrow coastal-season window. The bacteria may be microscopic, but the consequences are measured in trees and fruit.

The report arrives alongside a difficult season for Sonoma County apple growers, where early warm weather and fire blight have also been tied to a historically low Gravenstein harvest. The Sonoma apple industry has reported blight-related losses this season.

Scouting Before the Loss Spreads

For commercial apple and pear growers, the immediate instruction is unglamorous and familiar: inspect trees closely for symptoms. The point is not to make a dramatic diagnosis from the edge of a field, but to find trouble early enough that the grower can decide what to do with affected trees and blocks before losses widen.

That work is especially consequential in orchards near the Marin-Sonoma line, where the current reports describe a regional pattern rather than a single isolated tree. The reported damage in Chileno Valley gives growers a concrete reason to treat each scouting pass as an operational decision, not paperwork.

The size of the outbreak across West Marin, the final effect on this year's crop and the role of continued warm temperatures are not yet fully defined. What is clear is that a disease that can be easy to discuss in general terms has become expensive and local in at least one commercial orchard.