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A. Morales, B.A. Latorre, E. Piontelli, and X. Besoain. 2012. Botryosphaeriaceae species affecting table grape vineyards in Chile and cultivar susceptibility. Cien. Inv. Agr. 39(3): 445-458. Several Botryosphaeriaceae species have been identified as the causes of cankers and dieback of Vitis vinifera in several grape-growing regions around the world. This research was conducted to further study the species of Botryosphaeriaceae associated with table grapes in Chile, to estimate the prevalence and severity of the disease as a function of vineyard age, to study the susceptibility of table grape cultivars to infection by Botryosphaeriaceae species, and to evaluate the effect of tissue age on the infection caused by Botryosphaeriaceae species. Symptoms were characterized by the presence of the partial or total death of the grapevine cordons and distorted leaves. Brown V-shaped or U-shaped cankers and black spots were observed in cross-sections, while brown vascular streaks were observed in longitudinal sections of the cordons and trunks. Pathogenic isolates of Diplodia seriata, D. mutila and Spencermartinsia viticola were consistently obtained from wood cankers and/or vascular streaking; D. seriata was the most common (83.3%) Botryosphaeriaceae species. In 11-to 20-year-old vineyards, the disease incidence varied between 22.0 and 69.0%, and the severity varied between 6.0 and 21.3%. The table grape cultivars 'Thompson Seedless', 'Redglobe' and 'Flame Seedless' were equally susceptible to infection by D. mutila, D. seriata and S. viticola. The age of the inoculated tissue had no significant effect on the development of the vascular necrosis. This is the first report of D. mutila and S. viticola infections of grapevines in Chile.

Biocontrol of Rhizoctonia solani in tomatoes cultivated under greenhouse and field conditions was analyzed using the Trichoderma harzianum mutants Th650-NG7, Th11A80.1, Th12A40.1, Th12C40.1 and Th12A10.1 and ThF2-1, respectively. Their innocuousness on tomato cultivars 92.95 and Gondola (greenhouse assays), and on cultivar Fortaleza (field assays) was established. Alginate pellets (1.7 g pellets/L soil) containing c.a1 x 10 5 colony forming units (cfu)/g pellet were applied to a soil previously inoculated with R. solani at transplant (greenhouse) or to a naturally infected soil (field). *Corresponding authorControls considered parental wild strains, a chemical fungicide and no additions. Th11A 80.1, Th12A10.1 and Th650-NG7 prevented the 100% mortality of tomato plants cv. 92.95 caused by R. solani, and the 40% mortality in tomato plants cv. Gondola (greenhouse assays). Mortality reduction was reflected in canker level lessening and in plant parameters increases (development, fresh and dry weights). A different degree of susceptibility of tomato plants was observed, being Gondola cv. more resistant than 92.95 cv. to infection in a soil previously inoculated with R. solani.

In recent years, Chilean kiwifruit production has been affected by the phytopathogen Pseudomonas syringae pv. actinidiae (Psa), which has caused losses to the industry. In this study, we report the genotypic and phenotypic characterization of 18 Psa isolates obtained from Chilean kiwifruits orchards between 2012 and 2016 from different geographic origins. Genetic analysis by multilocus sequence analysis (MLSA) using four housekeeping genes (gyrB, rpoD, gltA, and gapA) and the identification of type III effector genes suggest that the Chilean Psa isolates belong to the Psa Biovar 3 cluster. All of the isolates were highly homogenous in regard to their phenotypic characteristics. None of the isolates were able to form biofilms over solid plastic surfaces. However, all of the isolates formed cellular aggregates in the air–liquid interface. All of the isolates, except for Psa 889, demonstrated swimming motility, while only isolate Psa 510 demonstrated swarming motility. The biochemical profiles of the isolates revealed differences in 22% of the tests in at least one Psa isolate when analyzed with the BIOLOG system. Interestingly, all of the isolates were able to produce indole using a tryptophan-dependent pathway. PCR analysis revealed the presence of the genes aldA/aldB and iaaL/matE, which are associated with the production of indole-3-acetic acid (IAA) and indole-3-acetyl-3-L-lysine (IAA-Lys), respectively, in P. syringae. In addition, IAA was detected in the cell free supernatant of a representative Chilean Psa strain. This work represents the most extensive analysis in terms of the time and geographic origin of Chilean Psa isolates. To our knowledge, this is the first report of Psa being able to produce IAA. Further studies are needed to determine the potential role of IAA in the virulence of Psa during kiwifruit infections and whether this feature is observed in other Psa biovars.