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Abstract: Large amounts of tomato fruits and derived products are produced in Argentina and may be contaminated by Alternaria toxins. Limited information is available on the genetic variability, toxigenicity, and pathogenicity of Alternaria strains occurring on tomato. We analyzed 65 Alternaria strains isolated in Argentina from tomato fruits affected by black mould and from tomato puree, using amplified fragment length polymorphisms (AFLPs) technique. AFLP analysis resolved the set of strains in 3 main clusters (DICE similarity values of 58 and 60%) corresponding to A. alternata/tenuissima (44 strains), A. arborescens (15 strains) and to an unknown group (6 strains). Most of the representative strains, belonging to each AFLP cluster, when cultured on rice, produced tenuazonic acid (up to 46,760mg/kg), alternariol monomethyl ether (AME, up to 1860mg/kg), and alternariol (up to 70mg/kg). The toxin profile related to the strains was not related to any AFLP cluster, except for AME which was produced at lower level by A. arborescens. Most of strains were pathogenic on two types of commonly cultivated tomato fruits. These findings provide new information on the variability within the Alternaria species complex associated with tomato disease. [Copyright &y& Elsevier]

A virus causing a severe disease of tomatoes in Argentina was identified as a strain of eggplant mosaic virus (EMV). It resembles the type, Abelia latent and various Andean potato latent strains of EMV in its host range and its transmissibility at a low rate by Epitrix sp. It differs from these strains, however, serologically and in some of its cytopathic effects. In serological agar gel double diffusion tests it proved to be closely related to the tomato white necrosis isolate of EMV studied by BARRADAS (1983) in Brazil. [ABSTRACT FROM AUTHOR]

The article reports on the association of Alternaria infectoria species-group with black point discoloration of wheat found in Argentina. It discusses the plant pathogens that cause dark brown or blackish discoloration, known as black point, around the embryo end of grains of wheat across the region of Buenos Aires Province in Argentina. It discusses the experiment conducted to identify the pathogens causing the black point disease which affect grain quality and impair flour, semolina and their products. The study revealed that grain samples are infected with Alternaria infectori and Alternaria alternata species-groups.

The article focuses on the study which identifies the causes of plant virus Nigrospora sphaerica to the leaf spots and twig and shoot blight on Blueberry in Argentina. The study evaluates pathogenicity of the leaves through the punctured of flamed needles and sprayed with spore suspension of distilled water. It was found out that after 20 days of inoculation, all wounded inoculated plants started to show disease symptoms. Moreover, fungus can create the wounds of the plants through the bites of the insects after a long-term wetness duration.