Los Angeles ? Scientists in California and Virginia will try to decode the genetic makeup of two plant-destroying microbes, including one blamed for killing tens of thousands of oak trees along the West Coast.

Backed by $4 million in federal grants, the scientists hope to sequence the genomes of the two species of Phytophthora to find ways to track, detect and eventually treat both diseases.

The more notorious microbe is P. ramorum, which causes sudden oak death syndrome. It has killed tens of thousands of black oak, coast live oak and tan oak trees in Northern California and southern Oregon since it appeared in 1995. This year, scientists discovered coast redwoods and Douglas fir are also susceptible, as are at least 14 other plant species.

“We’re really worried this could be the beginning of something terrible,” Jeffrey Boore of the U.S. Department of Energy’s Joint Genome Institute said of the infestation.

Scientists at the Walnut Creek institute and at the Virginia Bioinformatics Institute in Blacksburg, Va., also will sequence the genome of P. sojae, a related microbe responsible for soy rot, which is estimated to cause $1 billion in damages to soybean crops worldwide.

“The genome sequences of these two species will for the first time enable us to identify and target their vulnerabilities in order to control them,” said Brett Tyler, a Virginia molecular biologist.

Both genomes will be freely available on the Internet once completed.

The two funguslike organisms are closely related to algae. Among their relatives is P. infestans, the microbe responsible for Ireland’s potato famine in the 19th century. The name Phytophthora means “plant devourer” in Greek.

Because the microbes, called Stramenopiles or water molds, come from a different kingdom of life than most other pathogens, most pesticides and fungicides have no effect on them.

Funding for the one-year project comes from the National Science Foundation, U.S. Department of Agriculture and U.S. Department of Energy.