Plant Disease May Prompt Quarantine

Under pressure to take action on a potentially devastating forest disease in California, the federal government is preparing quarantine measures that would toughen existing restrictions on nursery operations and on the movement of green waste in 10 coastal counties.

The proposed federal regulations are stricter than existing state rules designed to prevent the spread of sudden oak death, which has killed thousands of oaks and sickened forest shrubs in Northern and Central California.

It is also possible that the U.S. Department of Agriculture could impose its quarantine on all of California, rather than just the 10 counties in which the epidemic has been confirmed. Everything from nursery shipments to firewood sales up and down the state could then be affected.

California officials are trying to avoid that, worried that a statewide quarantine would be costly and hard to enforce.

The federal crackdown looms as government agencies struggle to deal with a disease discovered less than a decade ago. It has claimed a growing list of forest victims in a widening range along the coast. Evidence of the disease has recently been detected in redwoods, although state researchers have not yet confirmed that the trees are vulnerable to the infection.

California and the federal government have come under criticism for not taking stronger actions to try to control the epidemic.

Worried that sudden oak death could move into its forests, Canada last year imposed import restrictions so severe that they have stopped the shipment of containerized nursery plants from California.

“It’s a concern to us,” said Shane Sela, forestry specialist for the western area of the Canadian Food Inspection Agency. “At the present time, there is no regulatory control to prevent movement of infested material from California to other parts of the U.S. We’d like to see some interstate controls.”

‘It’s Like Hitting

a Moving Target’

State and federal authorities say they have been hampered by a shortage of scientific information on the pathogen and the growing list of plants that carry it.

“It’s like hitting a moving target,” said Jonathan Jones, national forest pest manager for plant protection and quarantine in the USDA.

His agency expects to issue quarantine regulations within the next few weeks. Although not yet finalized, they apparently will broaden the state’s rules in a number of ways:

Whereas California now focuses its restrictions on the movement of plant material from infested areas sprinkled through the 10 counties, the federal rules would apply to all parts of those counties. That would increase the number of nurseries subject to inspections and testing of plants that can carry the disease.

The state now permits the movement of green waste from the infected counties to mulching facilities elsewhere in California. The federal regulations would not, raising questions about what some counties would do with huge quantities of green waste collected under state recycling laws.

The proposed USDA rules would require the debarking of logs and firewood before they could be shipped out of infected regions.

As envisioned, the federal quarantine would apply only to those counties in which the disease has been confirmed, ranging from Mendocino to Monterey.

But if the state does not rewrite its regulations to conform to the federal rules, the USDA could slap its restrictions on all of California.

“That would be terrible,” said Robert Falconer, director of government affairs for the California Assn. of Nurserymen.

Differing Effects

on Nurseries

The impact on wholesale nurseries would vary, he said. The plant types that have so far been infected with sudden oak death are not nursery mainstays, but a number of affected species are sold commercially. They include rhododendrons, coast live oaks, bay laurel and big leaf maple.

Before a nursery could ship plants of the affected species outside the quarantined area, the federal regulations would require inspections. If disease symptoms were found, testing would be required. The federal restrictions would also cover azaleas; state rules do not.

Falconer said his group favors a federal quarantine so that a patchwork of state-by-state regulations does not crop up. But the group views parts of the proposed federal rules as too restrictive. “And we’re not sure how they’re going to do all the inspections,” he said.

State regulators have been meeting with their federal counterparts, trying to bridge the gap between the two sets of rules. “I think we would like them to come around to our way of regulating,” said Nick Condos, senior agricultural biologist for the California Department of Food and Agriculture.

While federal and state authorities are debating quarantines, a UC Riverside plant pathologist wonders if any sort of quarantine would be effective.

Michael Coffey has spent years researching Phytophtora, to which the sudden oak death pathogen belongs. There are dozens of species of the fungus-like organism, including one that caused the Irish potato famine of the 1800s.

“If it’s anything like other Phytophtora,” he said, “a quarantine is unlikely to work.”