Browsing by Author "LATORRE, BA"

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    COMPARATIVE PROTEIN ELECTROPHORETIC AND ISOENZYMIC PATTERNS OF PHYTOPHTHORA-CRYPTOGEA ISOLATES FROM CHILEAN KIWIFRUIT AND NORTH-AMERICAN DECIDUOUS FRUITS
    (1995) LATORRE, BA; PEREZ, GF; WILCOX, WF; TORRES, R
    Isolates of Phytophthora from fruit crops, previously identified as P. cryptogea on the basis of standard morphological criteria, were compared using electrophoretic patterns of total soluble mycelial proteins and isozyme analysis. According to these criteria, all 33 isolates recovered from kiwifruit in Chile were similar or identical to isolates from California recovered from kiwifruit, apple, and cherry. In contrast, the Chilean and California isolates appeared no more related to New York isolates of P. cryptogea than they were to isolates of P. cactorum, P. cinnamomi, and P. megasperma that were similarly examined. Isolates identified as P. cryptogea from deciduous fruit crops in New York appear to belong to a different taxon than isolates of P. cryptogea from fruit crops in Chile and California.
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    EFFECT OF POTATO VIRUS-Y ON GROWTH, YIELD, AND CHEMICAL-COMPOSITION OF FLUE-CURED TOBACCO IN CHILE
    (1984) LATORRE, BA; FLORES, V; MARHOLZ, G
    The effect of potato virus Y (PVY) on growth, yield and chemical composition of flue-cured tobacco cultivars Coker 86 and NC-744 was primarily determined by the time of inoculation. On Coker 86, early inoculations (15 and 28 days after transplanting) caused height reductions of 37.0 and 34.7% and yield reductions of 71.5 and 74.8%, respectively. Effects were less detrimental on NC-744, suggesting this cultivar possesses a degree of tolerance to the Chilean necrotic strain of PVY. Nevertheless, plant height and dry weight were reduced 9.9 and 16.3% and 36.9 and 38.9%, respectively, by inoculations 15 and 28 days after transplanting. PVY also modified the chemical composition of cured leaves. Total nicotine content was always higher in cured leaves from diseased plants than in those from healthy controls. Because early inoculations caused the most detrimental effects, the 1st mo. after transplanting should be considered the most critical period for PVY infection.
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    ISOLATION OF PSEUDOMONAS-SYRINGAE PV SYRINGAE FROM CANKERS AND EFFECT OF FREE MOISTURE ON ITS EPIPHYTIC POPULATIONS ON SWEET CHERRY TREES
    (1985) LATORRE, BA; GONZALEZ, JA; COX, JE; VIAL, F
    Frequency of isolation of P. syringae pathovar syringae (Pss) from bacterial cankers on 3- to 4-yr-old sweet cherry trees [Prunus avium] (cultivar Napoleon) was highest between late winter (Aug.) and early spring (Sept.). Large, abrupt changes in epiphytic populations of Pss were found on dormant buds of ''Napoleon'' cherry shoots under field conditions. These changes closely followed the presence or absence of free moisture resulting from rainfall or dew. Populations of Pss greater than 104 colony-forming units/gram of buds were only recorded during wet periods; otherwise, populations remained low or undetectable. Field observations were corroborated by greenhouse experiments on detached, dormant cherry shoots where 10-fold or higher fluctuations in bacterial populations occurred in response to 24 h of wetness or dryness.
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    STRAIN IDENTIFICATION AND CROSS-PROTECTION OF POTATO VIRUS-Y AFFECTING TOBACCO IN CHILE
    (1985) LATORRE, BA; FLORES, V
    Necrosis severa, caused by potato virus Y (PVY), severely affects flue-cured, burley, and oriental tobaccos in Chile. PVY populations consisted of necrotic and nonnecrotic strains distinguished on the basis of the symptoms produced. Most Chilean isolates were identified as race I (MsMr) or race 3 (NsNr). However, a few were identified as race 2 (MsNr) on the basis of reactions they induced on tobacco cultivars susceptible and resistant to the root-knot nematode. PVY isolates were also distinguishable by their reactions on tobacco Virgin A Mutant, a noncompatible (apparently immune) reaction or compatible reactions that were either necrotic or nonnecrotic symptoms incited on veins or stems. The presence of necrosis did not necessarily appear to be associated with symptom severity. Most nonnecrotic PVY isolates exerted partial protection against a challenge inoculation with a necrotic strain, demonstrating the ocurrence of this phenomenon among PVY isolates and suggesting cross-protection as a possible mechanism for PVY control. Cross-protection may also play a significant role in the epidemiology of PVY diseases.