ABSTRACT. Optical sensors can be used to assess crop N status to assist with N fertilizer management. Differences between cultivars may affect optical sensor measurement. Cultivar effects on measurements made with the SPAD-502 (Soil Plant Analysis Development) meter and the MC-100 (Chlorophyll Concentration Meter), and of several vegetation indices measured with the Crop Circle ACS470 canopy reflectance sensor, were assessed. A cucumber (Cucumis sativus L.) crop was grown in a greenhouse, with three cultivars.

ABSTRACT. The spread of the epiphytic population of Xanthomonas campestris pv. vesicatoria and the disease it causes, bacterial leaf spot, were studied in field plots of pepper near Gainesville, Florida. In the summer of 1989, the epiphytic population of X. campestris pv. vesicatoria was dispersed to the west-northwest from point sources of diseased plants. Winds from the southeast during rainstorms were essential for the spread of bacteria in the field. In the autumn of 1989, a focus of bacterial leaf spot developed naturally near the centre of the experimental plot.

ABSTRACT. The aim of this research was to obtain information on the behaviour of the species under cultivation. Seeds were sown on December 18, 1992, in a field seedbed under plastic cover. Plants were taken to the field when 15 cm high (February 18, 1993). Three lines with 47 plants each were managed independently. Plants from Line 1 were harvested on August 4, Line 2 on August 19, and Line 3 on September 13, 1993. Mean fresh weight per plant for each line was 261, 207 and 337 g, and 88, 78 and 105 g, respectively, expressed in dry weight.

ABSTRACT. The South American Tortricid Moth (Meyrick, 1909) (Lepidoptera: Tortricidae) is often found damaging vineyards and other temperate fruit orchards, in Southern Brazil and Uruguay. This work was conducted to study the seasonal occurrence of A. sphaleropa adults in vineyards using sexual synthetic pheromone. Based on weekly evaluation of A.

ABSTRACT. The South American Tortricid Moth (Meyrick, 1909) (Lepidoptera:Tortricidae) is often found damaging vineyards and other temperate fruit orchards, in Southern Brazil and Uruguay. This work was conducted to study the seasonal occurrence of A. sphaleropa adults in vineyards using sexual synthetic pheromone. Based on weekly evaluation of A.

ABSTRACT. Plants were propagated by fruits and cuttings. Cuttings were rooted in two seasons:autumn (May 19, 1992), in a field nursery under plastic cover, and spring (September 14, 1992) in plastic containers under shade. Seeds were sown in a field nursery under plastic cover on June 8, 1992. Plants were taken to the field on November 25, 1992, planted at a spacing of 30 x 40 cm. For the three treatments, the mortality of plants after transplanting was 42, 4 and 46% respectively. Within each treatment, plants were harvested on February 5, 1993, November 12, 1993 and November 3, 1994.

ABSTRACT. The claim that organic agriculture produces higher levels of phytochemicals has been controversial for decades. Using strawberries as a model crop in field conditions, a preharvest leaf wounding stress was applied to study the production of phytochemicals in fruits. As a result phenolic compounds (PCs) and total soluble sugars increased significantly, where specific phenylpropanoids showed increment up to 137% and several genes related to PCs biosynthesis and sugar transport were overexpressed.

ABSTRACT. The claim that organic agriculture produces higher levels of phytochemicals has been controversial for decades. Using strawberries as a model crop in field conditions, a preharvest leaf wounding stress was applied to study the production of phytochemicals in fruits. As a result phenolic compounds (PCs) and total soluble sugars increased significantly, where specific phenylpropanoids showed increment up to 137% and several genes related to PCs biosynthesis and sugar transport were overexpressed.

RESUMEN. En este trabajo se evaluaron accesiones de frutos nativos de ?Arazá? (Psidium ­cattleianum), ?Guaviyú? (Myrcianthes pungens) y Guayabo del país? (Acca sellowiana) como parte de un programa de selección de variedades para obtener cultivares comerciales. El objetivo es ofrecer a los productores nuevas posibilidades de cultivos frutícolas locales y brindar a los consumidores alternativas alimenticias con reconocidas propiedades nutricionales y nutracéuticas.

RESUMEN. Las frutas y hortalizas pueden contener contaminantes que llegan al producto en cualquier punto de la cadena productiva.