Susceptibility of Pecan Cultivars to Cladosporium cladosporioides Species Complex

ABSTRACT

Recent studies have observed symptoms of leaf spot in pecan (Carya illinoinensis ) associated with species of the Cladosporium cladosporioides complex (C. cladosporioides, C. pseudocladosporioides , and C. subuliforme). Therefore, the present study aimed to investigate the pathogenicity of these Cladosporium spp. isolated from two pecan cultivars. Twenty-six isolates were used to inoculate leaflets of the cultivars, 'Barton' and 'Shawnee', with a spore suspension. The suspension was applied through drops on the surface of the leaflets, the material was kept in boxes, “gerbox”, in the incubation room. After 22 days, leaf spots varied from small circular brown to black stains, which indicated the advancement of the disease. The three Cladosporium sp. were pathogenic to pecan cultivars and there was a difference in susceptibility to C. pseudocladosporioides species between the 'Barton' and 'Shawnee' cultivars, where 'Shawnee' showed greater disease severity.

Keywords:
Carya illinoinensis; susceptibility; inoculation; breeding program; scab