ABSTRACT
Late blight, caused by the fungus Phytophthora infestans, is the most important and destructive disease of tomato crops, under low temperature and high humidity conditions. In order to evaluate the effectiveness of different fungicide groups and some mixtures on disease control, three experiments were carried out in a commercial field located in the counties of Piedade, Socorro, Bragança Paulista, state of São Paulo, during 2000 and 2001. The experiments were set in randomized blocks design with four replications and 24 plants per plot. The sprayings were carrie out in intervals from 7 to 10 days, using volumes from 600 to 1,000 L/ha. The evaluated criteria were: disease severity in leaves and stem, number of healthy and sick fruits, fresh mass of fruits and commercial yield. All the tested treatments proved to be superior to the control for all evaluated variables. The highest levels of control and yield were obtained with the treatments: cymoxanil+maneb+zinc-sulphate +azoxystrobin, propamocarb+cymoxanil+maneb+zinc-sulphate, metalaxyl-M+chlorothalonil, fenamidone, fenamidone+chlorothalonil, fenamidone+fosetil-Al, pyraclostrobin+metiram, dimetomorph+ chlorothalonil, propamocarb+chlorothalonil, propamocarb+azoxystrobin, famoxadone+ cymoxanil+mancozeb, dimetomorph+mancozeb, metalaxyl-M+mancozeb. The treatments cymoxanil+maneb+zinc-sulphate and fluazinam provided intermediary results, being superior to chlorothalonil.
KEY WORDS:
Lycopersicon esculentum
;
Phytophthora infestans
; chemical control.
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