Phylogenetic relationships between thirteen species of downy mildew and 103 species of Phytophthora (plant-pathogenic oomycetes) were investigated with two nuclear and four mitochondrial loci, using several likelihood-based approaches. Three Phytophthora taxa and all downy mildew taxa were excluded from the previously recognized subgeneric clades of Phytophthora, though all were strongly supported within the paraphyletic genus. Downy mildews appear to be polyphyletic, with graminicolous downy mildews (GDM), brassicolous downy mildews (BDM) and downy mildews with colored conidia (DMCC) forming a clade with the previously unplaced Phytophthora taxon totara; downy mildews with pyriform haustoria (DMPH) were placed in their own clade with affinities to the obligate biotrophic P. cyperi. Results suggest the recognition of four additional clades within Phytophthora, but few relationships between clades could be resolved. Trees containing all twenty extant downy mildew genera were produced by adding partial coverage of seventeen additional downy mildew taxa; these trees supported the monophyly of the BDMs, DMCCs and DMPHs but suggested that the GDMs are paraphyletic in respect to the BDMs or polyphyletic. Incongruence between nuclear-only and mitochondrial-only trees suggests introgression may have occurred between several clades, particularly those containing biotrophs, questioning whether obligate biotrophic parasitism and other traits with polyphyletic distributions arose independently or were horizontally transferred. Phylogenetic approaches may be limited in their ability to resolve some of the complex relationships between the “subgeneric” clades of Phytophthora, which include twenty downy mildew genera and hundreds of species.

Yeasts were isolated from grapes collected from a research vineyard at the WSU-IAREC, located at Prosser, WA. Species determination was based on cultural features, microscopic morphology, physiological tests and analysis of ITS and D1/D2 rDNA sequence data. Fifty-three species were found distributed among five fungal subphyla, a greater number than expected based on similar published studies. Within Saccharomycotina, 13 species in the genera Candida, Hanseniaspora, Metschnikowia, Meyerozyma, Pichia, Wickerhamomyces and Yamadazyma were determined. Isolates within the Metschnikowia pulcherrima clade appeared to possess considerable diversity. Pucciniomycotina was represented by 12 species, in Curvibasidium, Rhodosporidium, Rhodotorula, Sporidiobolus and Sporobolomyces. Five phylogenetically distinct species in the subphylum could not be assigned to any described species. Isolates in Ustilaginomycotina were placed in Pseudozyma except for a single strain determined to be Rhodotorula bacarum. Within Agaricomycotina, 17 species in the genera Cryptococcus, Cystofilobasidium, Hannaella, Holtermanniella and Mrakiella were determined. Seven species of yeastlike Pezizomycotina were found, representing classes Leotiomycetes, Dothideomycetes and Sordariomycetes. Isolates of Aureobasidium pullulans represented three phylogenetically distinct subspecific lineages. Seventeen species identified in this study were previously unreported from wine grapes and 18 species were unreported from North America. Several strains appear to represent undescribed species, including the recently described Curvibasidium rogersii.

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Brown spot, caused by Cladosporium spp., is becoming a problematic postharvest disease of late season table grape (Vitis vinifera) in the California central valley, and management is hindered by knowledge gaps in disease etiology and epidemiology. Brown spot is herein described as a pre- and postharvest dry rot typified by an external brown to black spot or black mycelium which encases the placenta. Isolates in the Cladosporium herbarum and C. cladosporioides species complexes were recovered from 85 and 5% of brown-spot affected berries, respectively. Five isolates in the C. herbarum species complex, representing three phylogenetically distinct species (C. limoniforme, C. ramotenellum, and C. tenellum), and one C. cladosporioides isolate all caused brown spot symptoms under cold-storage conditions, with and without mechanical wounding. Isolate virulence was similar (P > 0.05) based on disease incidence and severity on intact berries but severity varied on wounded berries (P < 0.001). Surface disinfestation reduced severity of cluster rot development following 2 weeks in cold storage (P = 0.027) but incidence was not affected (P = 0.17). This work provides foundational information on brown spot pathosystem etiology and biology in late-harvest table grape, which can be used to improve management.

Anthracnose caused by Colletotrichum species is one of the most frequent and damaging fungal diseases affecting avocado fruits (Persea americana Mill.) worldwide. In Chile, the disease incidence has increased over the last decades due to the establishment of commercial groves in more humid areas. Since 2018, unusual symptoms of anthracnose have been observed on Hass avocado fruits, with lesions developing a white to gray sporulation. Morphological features and multi-locus phylogenetic analyses using six DNA barcodes (act, chs-1, gapdh, his3, ITS, and tub2) allowed the identification of the causal agent as Colletotrichum anthrisci, a member of the dematium species complex. Pathogenicity was confirmed by inoculating healthy Hass avocado fruits with representative isolates, reproducing the same symptoms initially observed, and successfully reisolating the same isolates from the margin of the necrotic pulp. Previously, several Colletotrichum species belonging to other species complexes have been associated with avocado anthracnose in other countries. To our knowledge, this is the first record of C. anthrisci and of a species of the dematium species complex causing anthracnose on avocado fruits in Chile and worldwide.

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A collection of 30 Phytophthora cactorum and 12 P. pseudotsugae (subclade 1a) strains isolated from several recent surveys across California was phylogenetically compared to a worldwide collection of 112 conspecific strains using sequences from three barcoding loci. The surveys baited P. cactorum from soil and water across a wide variety of forested ecosystems with a geographic range of more than 1000 km. Two cosmopolitan lineages were identified within the widespread P. cactorum, one being mainly associated with strawberry production and the other more closely associated with apple orchards, oaks and ornamental trees. Two other well-sampled P. cactorum lineages, including one that dominated Californian restoration outplantings, were only found in the western United States, while a third was only found in Japan. Coastal California forest isolates of both Phytophthora species exhibited considerable diversity, suggesting both may be indigenous to the state. Many isolates with sequence accessions deposited as P. cactorum were determined to be P. hedraiandra and P. ×serendipita, with one hybrid lineage appearing relatively common across Europe and Asia. This study contains the first report of P. pseudotsugae from the state of California and one of the only reports of that species since its original description.

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