VIEW ARTICLE

Phytoalexinlike Compounds Apparently Involved in Strawberry Resistance to Phytophthora fragariae. Harry W. Mussell, Assistant Plant Pathologist, Boyce Thompson Institute for Plant Research, Inc., 1086 North Broadway, Yonkers, New York 10701; Richard C. Staples, Plant Biochemist, Boyce Thompson Institute for Plant Research, Inc., 1086 North Broadway, Yonkers, New York 10701. Phytopathology 61:515-517. Accepted for publication 25 November 1970. DOI: 10.1094/Phyto-61-515.

Inoculation of the red stele-resistant strawberry cultivars Surecrop and Stelemaster with either race A-2 or A-4 of Phytophthora fragariae resulted in the formation of two materials inhibitory to the growth of Cladosporium cucumerinum in a standard bioassay. These materials have not been detected in extracts from healthy roots, but appear in resistant cultivars within 48 hr after infection. Both of these compounds were partially inhibitory to mycelial growth of P. fragariae on either lima-bean agar or a synthetic medium. Inoculation of the susceptible cultivar Blakemore resulted in the appearance of only one of these compounds, and this compound was not detected until 5-8 days after infection.