Strobilurins and carboxamides in physiology and management of Alternaria sp. of tomato

The aim of this study was to evaluate the application effects of fungicides based on strobilurins and carboxamides on the physiology, management of Alternaria sp. and production of tomato fruits in a protected environment. Two experiments were carried out in Salto-SP in 2018 and 2019. The randomized block design was used, with seven treatments: inoculated control (application of water and inoculum with Altenaria sp.), absolute control (application of water), azoxystrobin, boscalid, boscalid + azoxystrobin, pyraclostrobin and boscalid + pyraclostrobin, and five replications. To verify the photosynthetic efficiency of plants, analysis of chlorophyll a fluorescence and leaf gas exchange was performed at 50, 95 and 120 DAT. It was also verified the disease severity (%) and finally and the total and commercial production of fruits. From the results, under this research conditions, the tested fungicide application promoted positive physiological responses in tomato plants, controlling early blight disease and increasing fruit production. The application of the fungicides boscalid and azoxystrobin + boscalid can be a management tool for Alternaria sp. for tomatoes, for controlling the progress of the disease as well as for promoting better physiological and productive responses.