This study aimed to investigate the reaction of unripe and ripe fruits of Capsicum spp. accessions to Colletotrichum gloeosporioides during the pre- and post-harvest periods, and to identify sources of resistance for use in plant breeding programs. Thirty-seven Capsicum spp. accessions of the Universidade Estadual do Norte Fluminense Darcy Ribeiro were evaluated. They were cultivated in a greenhouse and arranged in a completely randomized design with five replications. Twenty fruits from each accession were inoculated at two stages (unripe and ripe) in two different environments (fruits inoculated in the plant and detached fruit inoculated under laboratory conditions). The symptoms were assessed every 24 hours between the 1st and 8th days after inoculation. There were highly significant differences in the values of the area under the disease progress curve and in severity, considering all sources of individual variation and their interactions. Values of low and moderate correlation were observed for inoculation of unripe and ripe fruit in both environments. These results indicate the existence of distinct genes responsible for resistance at different stages of fruit development. Complete lack of symptoms was registered only for accessions UENF 1718 and UENF 1797 (C. baccatum var. pendulum).

Sementes infetadas constituem fonte primária de inóculo para epidemias da mancha bacteriana do tomate (Lycopersicon esculentum)que sob condições favoráveis podem resultar em rápido desenvolvimento da doença e severas perdas. O presente trabalho objetivou avaliar a eficiência do tratamento térmico a 70 ºC por 96 h na erradicação de Xanthomonas campestris pv. vesicatoria de sementes de tomate e seu efeito sobre a qualidade fisiológica e estrutura das sementes, por meio de microscopia eletrônica de varredura (MEV). Realizaram-se dois ensaios, e utilizando-se sementes inoculadas pelo método a vácuo com o isolado ENA 4463 a 10(7) ufc/ml em NaCl (0,85%). No primeiro ensaio compararam-se quatro tratamentos: sementes inoculadas (1), sementes inoculadas e tratadas a 70 ºC/96 h em estufa com circulação forçada de ar (2), sementes não inoculadas e não tratadas (3) e sementes não inoculadas e tratadas (70 ºC/96 h) (4). No segundo ensaio, apenas os tratamentos (1), (2) e (3) foram comparados. As amostras foram avaliadas quanto à qualidade fisiológica e recuperação da fitobactéria por meio de extração a vácuo seguido de riscagem em meios semi-seletivos, além de observações em MEV. Constatou-se eficiência de 100% e 99,96% na erradicação da bactéria no primeiro e segundo ensaio, respectivamente. Não houve nenhum efeito do tratamento térmico sobre a germinação. Observações ao MEV, revelaram alterações na estrutura superficial das sementes, com remoção, quebra e fusão de tricomas, além de danos à integridade das células bacterianas associadas à superfície do tegumento.

Infected seed is the primary source of tomato (Lycopersicon esculentum) bacterial spot causing a rapid development of the disease with severe yield losses under favorable environmental conditions. The present work was undertaken to evaluate the effect of heat treatment (70 ºC for 96 h) on germination and seed structure, as well as to determine the efficiency of heat therapy to prevent bacterial growth and disease establishment. Two experiments were carried out using tomato seeds inoculated by vacuum with Xanthomonas campestris pv. vesicatoria strain ENA 4463 adjusted to 10(7) cells.ml-1 followed by air-drying. In the first assay, four treatments were designed as follows: (1) inoculated seeds; (2) inoculation followed by heat treatment (70 ºC/96 h); and two controls, uninoculated seeds without (3) and with (4) heat treatment. In the second assay, three treatments: (1), (2) and (3) were compared. Samples from different treatments were evaluated for the physiological status of the seeds and presence of the bacteria. The latter was tested by recovering the bacteria by vacuum extraction, isolation in semi-selective medium and visualizations though scanning electron microscopy (SEM). The efficiency of the heat treatment as a method to control the disease ranged from 99,96 to 100% for the second and first assay, respectively. Furthermore, there was no significant effect of the heat on seed germination. However, under SEM, heat treated seed showed some superficial structural changes, characterized by a greater number of broken trichomes, and a deposition of trichomes randomly or organized in plates over the seed surface and morphological changes in the bacterial cell shape.