The scientific battle against the devastating fungal strain Phytophthora infestans -- commonly known as potato late blight -- has been elevated on international fronts, according to a report released this month by the Cornell-Eastern Europe-Mexico (CEEM) International Collaborative Project in Potato Late Blight Control.

P. infestans, the fungus blamed for the Irish potato famine of the 1840s, is currently staging a resurgence in which, scientists agree, the new strains are far more aggressive than the original outbreak 150 years ago.

Three approved projects to fight the fungus include:

-- Late Blight in Siberia and Russian Far East.

This study will examine the P. infestans fungus in Siberia and the Russian Far East, looking specifically for pathogenic characteristics that exacerbate the late blight problem. Ultimately, this study will lead to determining effective and environmentally benign control strategies.

Yuri T. Dyakov, of Moscow University, Russia, and William E. Fry, Cornell professor of plant pathology, are the primary investigators. This two-year $38,000 grant was given by the U.S. Civilian Research Development Foundation for the Independent States of the Former Soviet Union.

-- Identification Of Potatoes Resistant To Late Blight.

In 1980 a severe outbreak of late blight in Poland reduced potato crop yield by 30 percent. Researchers at the Mlochow Research Institute in Poland have spent the past three decades developing parental lines of potato cultivars that resist late blight well.

Between 1992 and 1995, the United States has suffered its worse years of losing potatoes to blight, with estimates of crop loss at more than $200 million. Maria T. Sieczka and Ewa Zimnoch-Guzowska of the Mlochow Research Institute will investigate which wild varieties of potato cultivars can be harvested for their genotypes, in order to seek truly stable resistance. American scientists on the project include Charles R. Brown, of the U. S. Department of Agriculture, currently on research sabbatical at Cornell; and John P. Helgeson, also of the U.S.D.A., who is examining plant disease resistance research at the University of Wisconsin-Madison.

The best performing genotypes of potato cultivars resistant to late blight will be tested in Toluca Valley of Mexico under the auspices of PICTIPAPA, an international late blight research cooperative. There, the potatoes will be placed under severe infection pressure. Investigators say that results and information generated by this project will be in the public domain.

This three-year project is being funded by a $100,000 grant from the U. S. Department of Agriculture/Foreign Agriculture service.

-- Genetic Variability Of P. Infestans In Mexico And The Netherlands.

Scientists from The Netherlands, Mexico and the United States will study the sexual reproduction of the P. infestans fungus to ascertain environmentally benign methods of controlling it.

Johannes Henri Marinus Schneider of Mexico, Lod Turkensteen of The Netherlands, Niklaus Grunwald of Mexico, and Fry are the principal investigators.

The scientists will study the oospore formation, survival and infection in the Toluca Valley. They also will address the fungus's aggressiveness, virulence and molecular genetic fingerprinting patterns to determine the role of oospores in late blight's epidemiology. Further, comparison testing will occur on the fungus's hidden virulence between the Mexican and Dutch strains.

This three-year project is funded by a $353,000 grant from the Dutch Potato Seed Industry, with additional financial and technical support from PICTIPAPA and CEEM; the project is scheduled to begin this April.

"Mexican researchers at the National Potato Program over the years have had a good reputation in developing several potato varieties with field resistance to late blight," said K. V. Raman, executive director of CEEM. "Ours and PICTIPAPA's aim is to work in close collaboration with this program on an equal partnership basis. Their expertise is crucial."