|Fernandez-Pavia, S.P. - PICTIPAPA, MEXICO|
|Fry, W. - CORNELL UNIV, NY|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2001
Publication Date: June 1, 2001
Citation: FERNANDEZ-PAVIA, S., GRUNWALD, N.J., FRY, W.E. INFECTIVITY AND FORMATION OF OOSPORES OF PHYTOPHTHORA INFESTANS IN THE TOLUCA VALLEY, MEXICO. PHYTOPATHOLOGY. 91(6):S28. 2001. Technical Abstract: In 1998 a moderate but sustained late blight epidemic was created in a large potato plot (cv. Alpha) with the objective of producing oospores that would infest the soil for subsequent growing seasons. In 1999 and 2000 we planted 18-plant plots each in the infested and adjacent uninfested area. The number of primary stem lesions and disease severity were significantly higher in plots from the infested area compared to the uninfested area. I November, January, and June of 1999 and 2000 infectivity of soil-borne oospores from these naturally infested soils were tested with a bioassay under controlled conditions. Oospores remained infective for at least two years. In a separate experiment leaflets from the potato cv. Alpha with coalescent double lesions were collected to check for oospore formation. Oospores formed readily on potato leaflets under field conditions. In another comparative study fewer oospores were observed in soils from the Toluca valley than in soils collected from 2 other potato growing areas of Mexico.