ABSTRACT. The sensitivity of Venturia inaequalis to trifloxystrobin and difenoconazole was studied in Uruguay. Populations of V. inaequalis were collected from apple orchards with different histories of trifloxystrobin use. Sensitivity of populations to trifloxystrobin was analysed using a method for testing spore germination published by FRAC, using a discriminatory concentration of 2.0 mg a.i./l. Resistance to trifloxystrobin was widespread in the region of commercial apple production with resistance detected in all orchards examined, the incidences ranging from 3% to 95%.

SUMMARY. Togninia minima (anamorph Phaeoacremonium aleophilum) is one of the main fungi responsible for trunk diseases of grapevines and other woody hosts worldwide. Sequences of protein-coding genes of isolates from countries in different continents have been published, presenting a useful resource for examination of the diversity and spatial distribution of T. minima genotypes.

ABSTRACT. Chemical communication among kin bacteria modulates diverse activities. Despite the general consensus that signaling among non-kin organisms is likely to influence microbial behavior, there is limited information on the potential for microbial interactions to alter microbial phenotypes in natural habitats. We explored patterns of interaction that alter inhibitory phenotypes among Streptomyces isolates from distinct communities.

ABSTRACT. Soil quality improvement by reducing soil tillage is one tool of sustainable agriculture. Covers crops left on soil surface prevent soil erosion, reduces evapotranspiration and weeds, and improves soil infi ltration; key factors for a successful vegetable production on heavy clay soils. The objective of this research was to evaluate the effect of cover crops plus ridge tillage on soil water content, soil, physico-chemical and biological properties and on vegetable yield.

RESUMEN. La solarización es la cobertura hermética del suelo, humedecido a capacidad de campo con polietileno transparente ultravioleta (UV) durante un tiempo variable. Mediante la captura de energía solar se aumenta la temperatura del suelo, perjudicando las semillas de malezas anuales. Esta técnica fue evaluada en almácigos de cebolla con excelentes resultados por INIADIGEGRA-FAGRO en 2005-2006 en tres localidades.

RESUMEN. El rendimiento potencial del cultivo de tomate para industria en el Uruguay según experimentos en el país es de 90 Mg ha-1. En contraposición, la productividad promedio del cultivo a nivel comercial no supera los 50 Mg ha-1. Este trabajo tiene por objetivo determinar cuales son las causas principales que determinan las diferencias de rendimiento entre productores de tomate para industria, estableciendo un orden jerárquico de factores determinantes. Para esto, se realizó un análisis de los factores que afectaron el rendimiento en los sistemas de producción en la zafra 2007/08.

ABSTRACT. Cryptoblabes gnidiella (Millière) (Lepidoptera: Pyralidae) has been known in Uruguay for 30 years and only in vineyards, despite being polyphagous. In recent years, this pest has caused sporadic but serious damage on some grapevine cultivars. Understanding the insect's phenology and developing a monitoring program are essential aspects of integrated pest management.

ABSTRACT. Cryptoblabes gnidiella (Millière) (Lepidoptera:Pyralidae) has been known in Uruguay for 30 years and only in vineyards, despite being polyphagous. In recent years, this pest has caused sporadic but serious damage on some grapevine cultivars. Understanding the insect's phenology and developing a monitoring program are essential aspects of integrated pest management.

ABSTRACT. A vineyard in south-central Chile was surveyed during five growing seasons to analyze the increase over time in the number of plants infected with Grapevine leafroll-associated virus-1, -2 and -3. At the end of the study, GLRaV-3 was found to be the most prevalent virus, with 46% of plants infected by this pathogen. GLRaV-2 infected 13% of plants, and GLRaV-1 infected 12%. Considering all three viruses together, the prevalence of infection increased exponentially from 14% of the plants at the beginning of the study period to 68% at the end.

ABSTRACT. Bacterial canker caused by Clavibacter michiganensis subspecies michiganensis (Cmm) has been a threat to tomato production in Uruguay for several years. In this study, 39 Cmm strains were collected from several outbreaks and production areas in Uruguay, and were identified by molecular assays and pathogenicity tests on a susceptible cultivar of tomato. In addition, a TaqMan assay targeting a putative two-component system sensor kinase gene demonstrated good specificity with all strains tested and gave no false negative results.