Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Occurrence and interaction of Aspergillus flavus with other fungi on almonds.

Abstract

The occurrence of the aflatoxin-producing fungi of the A. flavus group (AF) on samples from 89 locations in Calif. was influenced by other fungi on the kernels. Fruit of almond cvs. Milo, Nonpareil, and Ne Plus were inoculated before hull dehiscence with dry conidia of aflatoxin-producing aspergilli alone or in combination with groups of fungi (1975) or individual isolates (1976). Fungi used included yeasts, Monilinia [Sclerotinia] fructicola, Ulocladium atrum, U. chartarum, Drechslera [Cochliobolus] spicifer, Fusarium roseum, Rhizopus stolonifer, Cladosporium cladosporioides, Penicillium funiculosum and A. ficuum. The presence of other fungi with A. flavus or A. parasiticus generally reduced the number of isolates of AF that were recovered from hulls and kernels. Fungi requiring high moisture appeared antagonistic to AF in colonizing kernels. U. chartarum reduced the isolation of A. flavus most significantly.<new para>ADDITIONAL ABSTRACT:<new para>Fungi were isolated from >90% of the kernels sampled from 89 commercial orchards in California. Aspergillus niger and Alternaria spp. were most common on the disinfested kernels, but Aspergillus and Penicillium spp. predominated on nondisinfested kernels. Fruit of almond cultivars were inoculated before hull dehiscence with dry conidia of aflatoxin-producing A. spp. alone or in combination with groups of fungi or individual isolates. The presence of other fungi with A. flavus or A. parasiticus generally reduced the number of isolates of A. flavus or A. parasiticus that were recovered from hulls and kernels. Fungi requiring high moisture appeared antagonistic to A. flavus in colonizing almond kernels. Ulocladium atrum reduced the isolation of A. flavus most significantly.