Browsing by Author "Wilcox, WF"

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    Crown and root rots of table grapes caused by Phytophthora spp. in Chile
    (BUNDESANSTALT ZUCHTUNGS FORSCHUNG KULTURPFLANZEN, 1997) Latorre, BA; Wilcox, WF; Banados, MP
    Phytophthora crown and root rot of grapevine (Vitis vinifera L.) occurs frequently in Chile, where grapes are cultivated on their own roots. P. cinnamomi, P. cryptogea, and P. drechsleri were isolated from diseased root or crown tissue of the table grape cvs Flame Seedless, Italia, Red Globe, and Thompson Seedless with P. cryptogea being the most frequently isolated species. These pathogens were identified on the basis of standard morphological and cultural features and were compared by SDS-PAGE profiles of mycelial proteins. All isolates were pathogenic on 1-year-old cane segments and 1-year-old rooted grapevines of cvs Thompson Seedless and Red Globe. The latter cultivar was more susceptible than Thompson Seedless. P. cinnamomi and P. cryptogea have been associated with root rot of grapevines elsewhere, but this is the first report of P. drechsleri as a pathogen of grapevines and the first report of Phytophthora spp. affecting table grapes in Chile.
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    Identities and geographic distributions of Phytophthora spp. causing root rot of red raspberry in Chile
    (AMER PHYTOPATHOLOGICAL SOC, 2002) Wilcox, WF; Latorre, BA
    Five identified and two unidentified Phytophthora spp. were isolated from diseased roots of dead or declining red raspberry (Rubus idaeus L.) plants sampled from 18 plantations along a >1,000-km north-south axis in Chile. The array of Phytophthora spp. isolated was strongly associated with geographical location. P. fragariae var. rubi was recovered from 75 and 60% of the plantations in the southern (40degrees16' to 40degrees53' S latitude) and central (34degrees35', to 37degrees23' S latitude) production sectors, respectively, but was not recovered from any plantation in the northern sector (32degrees43' to 33degrees45' S latitude). Similarly, P. megasperma and P. gonopodyides were recovered from multiple plantations in the southern and central sectors but were not recovered in the northern sector. In contrast, R cryptogea was recovered from 80% of the plantations in both the northern and central sectors but not from any plantation in the south, whereas P citricola was isolated from diseased plants in all sectors. In subsequent pathogenicity trials, P. citricola, P. cryptogea, and an unidentified Phytophthora sp. were equally and highly virulent on 'Heritage' red raspberry in each of three greenhouse experiments. The other species were less virulent in the experiment when soil temperatures were highest (mean weekly maximum = 27.5degreesC) relative to the other two experiments when temperatures were more moderate (mean weekly maxima of 19.9 and 23.7degreesC). Isolates identified as R cryptogea were very similar to R cryptogea isolates recovered previously from kiwi fruit in Chile and from deciduous fruit trees in California with respect to morphological characters and electrophoretic banding patterns of soluble mycelial proteins. Using the same criteria, isolates identified as R gonopodyides were very similar to isolates recovered earlier from deciduous fruit crops in New York, which previously were identified as R cryptogea sensu lato but are hereby reclassified as P. gonopodyides.
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    Phytophthora species associated with crown and root rot of apple in Chile
    (AMER PHYTOPATHOLOGICAL SOC, 2001) Latorre, BA; Rioja, ME; Wilcox, WF
    Phytophthora cactorum, P. cryptogea, P. gonapodyides, and P. megasperma were isolated from necrotic root and crown tissues or the rhizospheres of apple trees exhibiting typical symptoms of Phytophthora root and crown rot in the Central Valley of Chile. Representative isolates of all four species were pathogenic on a variety of apple rootstocks and scions in trials conducted on excised shoots and 1-year-old MM.106 rootstock grown for 4 months in infested potting medium. P. cactorum was the most frequently isolated species and the most virulent in pot tests, although a significant Phytophthora sp.-apple genotype interaction was observed. This is the first report of any species other than P. cactorum causing root and crown rot of apple trees in Chile.