The fungus thrives in cooler, wet conditions found along the California coast. But scientists don't know whether individual trees or dense stands are vulnerable and if positions on north or south slopes matter. While insecticides can control beetles and prolong a tree's life, scientists need to test chemicals in the lab to find a fungicide that might control the fungus. A new field experiment was launched this month to learn whether oaks under stress from lack of water could be vulnerable to the disease. Oak tree leaves will be periodically collected and placed in pressure chambers.
Air pressure is applied until water seeps from a leaf's cut end.
Lab work also is increasing as scientists coax the fungus to run its course on oak seedlings. Seedlings of bay laurel, manzanita, madrone, Douglas fir, buckeye and redwood also will be infected to learn if the fungus might spread beyond oaks. UC Berkeley scientists will determine how widespread the disease has become and target problem areas. Satellite images will be gathered and combined with aerial and roadside surveys. High resolution digital surveys also are planned.