Effects of Hull Abscission and Inoculum Concentration on Severity of Leaf Death Associated with 'Hull' Rot of Almond. B. L. Teviotdale, Department of Plant Pathology, University of California, Davis/Kearney Agricultural Center, Parlier 93648. T. J. Michailidcs, Department of Plant Pathology, and D. A. Goldhamer, Department of Land, Air and Water Resources, University of California, Davis/Kearney Agricultural Center, Parlier 93648; and M. Viveros, University of California Cooperative Extension, Bakersfield 93370. Plant Dis. 80:809-812. Accepted for publication 9 April 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0809.

Almond fruit of cv. Nonpareil with slightly (1 to 10%), partially (15 to 40%) or almost completely (70 to 95%) abscised hulls were inoculated with Rhizopus stolonifer in 1991 and with R. stolonifer or Monilinia fructicola in 1992. More leaf death occurred both years near inoculated fruits with slightly or partially abscised hulls than near fruits with almost completely abscised hulls. Leaf death was greater near hulls inoculated with M. fructicola than with R. stolonifer in 1992. Disease severity did not differ among fruit with partially abscised hulls inoculated with 103, 104, or 105 spores of R. stolonifer per ml in 1991, and with the same concentrations of R. stolonifer, M. fructicola, or M. laxa in 1992. More leaf death occurred near fruit inoculated with M. laxa than with R. stolonifer and M. fructicola in 1992.

Keyword(s): Prunus dulcis, R. arrhizus, R. circinans