Virulence and Cultural Characteristics of Two<i>Aspergillus flavus</i>Strains Pathogenic on Cotton

Abstract

Cotty, P. J. 1989. Virulence and cultural characteristics of two Aspergillusjlavus strains pathogenic on cotton. Phytopathology 79:808-814. Seventy Aspergillus flavus isolates from Arizona desert valleys were sorted into two distinct strains on the basis of sclerotial size, cultural characteristics, and virulence to cotton. Strain L isolates produced large sclerotia (over 400 /lm in diameter), and strain S isolates produced small sclerotia (less than 400 /lm in diameter). Strain S isolates produced greater quantities of sclerotia in a wider assortment of media and a broader temperature range than strain L isolates. Isolates of both strains exhibited pH homeostasis in culture. However, the strains maintained different pH values. Strain S isolates produced more aflatoxin than strain L isolates in culture~ however, the strains produced similar aflatoxin levels in