Sugar Pine

Washington, Aug. l5.-Blister rust infection was recently found on sugar pine in northern California and southern Oregon by J. L. Mielke and W. W. Wagener of the Division of Forest Pathology, Bureau of Plant Industry, U. S. Department of Agriculture. This is the first known oc. curren'ce of the disease in California. I{owever, the relative susceptibility of sugar pine had been studied previously by planting young trees in infected areas of British Columbia and northwestern Oregon lvhere it was found that the sugar pine is more susceptible to attack than either eastern white pine or the western white pine, the other two of the American white pines which are especially valuable as forest trees.

Blister rust, a fatal disease of white pines, became established in the Pacific Northwest as a result of diseased white pine planting stock introduced from Europe and planted near Vancouver, B. C., in 1910. Its presence in western British Columbia and western Washington was first discovered in 1921. Since then it has spread through natural means into the commercial western white pine belt in eastern Washington, northern Idaho and western Montana. It has gradually extended southward towards the sugar pine belt of southern Oregon and northern California.

During the past several years infection on currant and gooseberry plants, the alternate hosts of the rust, has been found at several points within the sugar pine belt of Oregon and rust outbreaks already have appeared on the sugar pine in Oregon.

Control plans have been developed by the Bureau of Entomology and Plant Quarantine and ,control work aimed at safeguarding the highly valuable sugar pine stands is already well under way. At the close of the 1935 field season about 375,000 acres of sugar pine forest land had been treated by the removal of the currant and gooseberry plant3 from within and near the pine stands. Approximately 2,500 workers, financed on emergen,cy funds, are at work on the blister rust control in California and Oregon this season.