Validação dos sistemas de alerta Machardy e Colpam 40® para previsão da requeima do tomateiro em Caçador, SC

Abstract

Two warning systems for late blight in tomato were evaluated in two growing seasons in Caça dor Municipality, Santa Catarina State (SC), Bra zil. In the first growing season, as warming for fungicide spraying in late blight control, the systems MacHardy (modified) and Colpam 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 conventiona l method. The hybrid Carmen ha d higher productivity than 'Santa Clara'; however, there wa s no significant difference between the warning systems and the conventional method for the same cultivar. There was no significant difference between the conventiona l method a nd Colpa n 4 0 v.36, n.3, p.210-215, 2010. 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 rela tive to the conventiona l method. T reatments were not significantly different rega rding late blight, except for the highest severity level with Colpa n 40 ® in which the disea se intensity wa s higher. This work demonstrated the feasibility of both warning systems for late blight control in the region of Caçador Municipality.A tomaticultura se destaca como sendo a terceira ocupação hortícola cultivada em Santa Catarina e praticada em mais de dez mil estabelecimentos rurais. Na microrregião de Joaçaba esta atividade corresponde a 74,7% da área cultivada no estado, com destaque ao município de Caçador, responsável por 87,8% da produção desta microrregião (7) e com produtividade média de 58 t ha -1 (11