Two warning systems for late blight in tomato were evaluated in two growing seasons in Caçador Municipality, Santa Catarina State (SC), Brazil. In the first growing season, as warming for fungicide spraying in late blight control, the systems MacHardy (modified) and olpam 40® were compared to the conventional method based on the calendar in the hybrid 'Carmen' and the cultivar 'Santa Clara'. Both warning systems led to 34.6% and 42.3% reduction, respectively, in fungicide spraying, relative to the conventional method. The hybrid Carmen had higher productivity than 'Santa Clara'; however, there was no significant difference between the warning systems and the conventional method for the same cultivar. There was no significantdifference between the conventional method and Colpan 40® concerning late blight control for the hybrid 'Carmen'. In the second growing season, only the hybrid 'Carmen' was used to compare both warning systems with the conventional method, and Colpan 40® was evaluated at two severity levels (8 and 10). There was no significant difference in the productivity among treatments. As regards spraying frequency there was a decrease by 42.8% and 60.7% for the levels 8 and 10, respectively, with Colpan 40® and by 39.2% with MacHardy system relative to the conventional method. Treatments were not significantly different regarding late blight, except for the highest severity level with Colpan 40 ® in which the disease intensity was higher. This work demonstrated the feasibility of both warning systems for late blight control in the region of Caçador Municipality.
Phythophthora infestans; Lycopersicon esculentum Miller; Solanum lycopersicum L; pest management
