Identification of Species of Botryosphaeriaceae Causing Bot Gummosis in Citrus in California

Members of the Botryosphaeriaceae family are known to cause Bot gummosis on many woody plants worldwide. To identify pathogens associated with Bot gummosis on citrus in California, scion and rootstock samples were collected in 2010 and 2011 from five citrusgrowing counties in California. Symptoms observed on citrus included branch cankers, dieback, and gumming. Various fungal species were recovered from necrotic tissues of branch canker and rootstock samples. Species were identified morphologically and by phylogenetic comparison as ‘Eureka’ lemon, ‘Valencia’, ‘Washington Navel’, ‘Fukumoto’, grapefruit, ‘Satsuma’, and ‘Meyer’ lemon. Species were identified morphologically and by phylogenetic comparison of the complete sequence of the internal transcribed spacer regions, β-tubulin gene, and elongation factor α-1 genes with those of other species in GenBank. A consensus-unrooted most parsimonious tree resulting from multigene phylogenetic analysis showed the existence of three major clades in the Botryosphaeriaceae family. In total, 74 isolates were identified belonging to the Botryosphaeriaceae family, with Neofusicoccum spp., Dothiorella spp., Diplodia spp., (teleomorph Botryosphaeria), Lasiodiplodia spp., and Neoscytalidium dimidiatum (teleomorphs unknown) accounting for 39, 25, 23, 10, and 3% of the total, respectively. On inoculated Eureka lemon shoots, lesion length was significantly different (P \u3c 0.05) among 14 isolates recovered from portions of cankered tissues of the original trees. Lesion lengths were significantly longer (P \u3c 0.05) for shoots inoculated with isolates of Neofusicoccum luteum and shorter for shoots inoculated with isolates of Dothiorella viticola (P \u3c 0.05) than those of other species. Identifying the distribution and occurrence of these fungal pathogens associated with Bot gummosis is useful for management applications during occasional outbreaks in California

Identification of Species of Botryosphaeriaceae Causing Bot Gummosis in Citrus in California

Members of the Botryosphaeriaceae family are known to cause Bot gummosis on many woody plants worldwide. To identify pathogens associated with Bot gummosis on citrus in California, scion and rootstock samples were collected in 2010 and 2011 from five citrusgrowing counties in California. Symptoms observed on citrus included branch cankers, dieback, and gumming. Various fungal species were recovered from necrotic tissues of branch canker and rootstock samples. Species were identified morphologically and by phylogenetic comparison as ‘Eureka’ lemon, ‘Valencia’, ‘Washington Navel’, ‘Fukumoto’, grapefruit, ‘Satsuma’, and ‘Meyer’ lemon. Species were identified morphologically and by phylogenetic comparison of the complete sequence of the internal transcribed spacer regions, β-tubulin gene, and elongation factor α-1 genes with those of other species in GenBank. A consensus-unrooted most parsimonious tree resulting from multigene phylogenetic analysis showed the existence of three major clades in the Botryosphaeriaceae family. In total, 74 isolates were identified belonging to the Botryosphaeriaceae family, with Neofusicoccum spp., Dothiorella spp., Diplodia spp., (teleomorph Botryosphaeria), Lasiodiplodia spp., and Neoscytalidium dimidiatum (teleomorphs unknown) accounting for 39, 25, 23, 10, and 3% of the total, respectively. On inoculated Eureka lemon shoots, lesion length was significantly different (P \u3c 0.05) among 14 isolates recovered from portions of cankered tissues of the original trees. Lesion lengths were significantly longer (P \u3c 0.05) for shoots inoculated with isolates of Neofusicoccum luteum and shorter for shoots inoculated with isolates of Dothiorella viticola (P \u3c 0.05) than those of other species. Identifying the distribution and occurrence of these fungal pathogens associated with Bot gummosis is useful for management applications during occasional outbreaks in California

Fungal trunk pathogens of Sultana Seedless vineyards in Aegean region of Turkey

In recent years, grapevine trunk diseases have become a problem in Sultana Seedless vineyards of Manisa and Izmir provinces (Aegean Region, Turkey). A field survey was conducted in 2013 in these provinces (in 8 cities and 80 vineyards) to determine disease incidence, fungal species associated with grapevine trunk diseases and pathogenicity. Symptomatic vines were grouped by two different grapevine trunk disease symptoms: (1) typical tiger-striped leaves, (2) dead arm, shoot decline or apoplexy. Over 80% of vineyards in these areas were positive for at least one characteristic trunk disease symptom. Incidence of tiger-stripe symptom ranged from 2.9-15% and incidence of apoplexy ranged from 0-4.2%. Eight fungal species in five fungal families were identified from declining grapevines based on morphological and molecular (ITS, ß-tubulin and EF1-a) studies including, Botryosphaeria dothidea, Diplodia seriata, Lasiodiplodia theobromae, Neofusicoccum parvum, Diaporthe ampelina, Phaeomoniella chlamydospora, Togninia minima and Fomitiporia mediterranea. Overall, D. ampelina was the most frequently recovered fungus from symptomatic grapevine tissues followed by botryosphaeriaceous fungi, P. chlamydospora, F. mediterranea and T. minima. Pathogenicity tests confirmed all eight fungi as pathogens of grapevine in these regions with N. parvum being the most virulent among the fungi tested. © Firenze University Press

Identification, pathogenicity and abundance of Paracremonium pembeum sp. nov. and Graphium euwallaceae sp. nov.-two newly discovered mycangial associates of the polyphagous shot hole borer (Euwallacea sp.) in California

PubMedID: 26740544Fusarium euwallaceae is a well-characterized fungal symbiont of the exotic ambrosia beetle Euwallacea sp. (polyphagous shot hole borer [PSHB]), together inciting Fusarium dieback on many host plants in Israel and California. Recent discoveries of additional fungal symbionts within ambrosia beetle mycangia suggest these fungi occur as communities. Colony-forming units of Graphium euwallaceae sp. nov. and Paracremonium pembeum sp. nov., two novel fungal associates of PSHB from California, grew from 36 macerated female heads and 36 gallery walls collected from Platanus racemosa, Acer negundo, Persea americana and Ricinus communis. Fungi were identified based on micromorphology and phylogenetic analyses of the combined internal transcribed spacer region (nuc rDNA ITS1-5.8S-ITS2 [ITS barcode]), elongation factor (EF 1-a), small subunit (18S rDNA) sequences for Graphium spp., ITS, EF 1-a, calmodulin (cmdA), large subunit of the ATP citrate lyase (acl1), b-tubulin (tub2), RNA polymerase II second largest subunit (rpb2) and large subunit (28S rDNA) sequences for Paracremonium spp. Other Graphium spp. recovered from PSHB in Vietnam, Euwallacea fornicatus in Thailand, E. validus in Pennsylvania and Paracremonium sp. recovered from PSHB in Vietnam were identified. F. euwallaceae was recovered from mycangia at higher frequencies and abundances in all hosts except R. communis, in which those of F. euwallaceae and P. pembeum were equal. P. pembeum was relatively more abundant within gallery walls of A. negundo and R. communis. In all hosts combined F. euwallaceae was relatively more abundant within PSHB heads than gallery walls. All three fungi grew at different rates and colonized inoculated excised stems of P. americana and A. negundo. P. pembeum produced longer lesions than F. euwallaceae and G. euwallaceae on inoculated avocado shoots. Results indicate PSHB is associated with a dynamic assemblage of mycangial fungal associates that pose additional risk to native and nonnative hosts in California. © 2016 by The Mycological Society of America