In order to evaluate chemical control of bacterial spot on tomato for industrial processing, two field trials were carried out at the Unilever Bestfoods experimental station, in Goiânia, Goias state, Brazil. The first trial was in a randomized complete block design, with 15 treatments and three replications, using the hybrid Heinz 9992 inoculated with Xanthomonas perforans. The second trial was in a split-plot randomized complete block design with chemical foliar applications (10 treatments) and hybrids (Hypeel 108 and U2006) as factors. Plants were inoculated with X. perforans and X. gardneri. In both trials the chemicals, in different number of applications and combinations, were: acibenzolar-S-methyl (ASM); famoxadone + mancozeb; metiram + pyraclostrobin; phosphite PK; benzalkonium chlorides; cuprous oxide, and copper hydroxide (SC, WP and WG). For both trials, disease severity on leaves, number of fruits with symptoms and yield were evaluated. In the second one, sunscald was also evaluated. For the first trial, significant severity differences (p>0.05) among treatments were observed only in the first two evaluations, but none of them differed from the water check control. In the second trial, significant differences were detected only in foliar severity in first evaluation for hybrids. For number of fruits with symptoms and sunscald, besides hybrids, interaction among factors was also significant. 'U2006' was more resistant than 'Hypeel 108', which also had highest sunscald values, but concerning fruits with symptoms, the opposite was observed. The two factors were significant for yield data, 'U2006' yielded better than 'Hypeel 108'. Despite none of the treatments have differed in yield from the water control, famoxadone + mancozeb, which resulted in the highest yield, differed from copper hydroxide, ASM - famoxadone + mancozeb, and benzalkonium chlorides. ASM and famoxadone + mancozeb were those that promoted benefit/cost relation higher than 1.
Solanum lycopersicum; Xanthomonas perforans; Xanthomonas gardneri; pesticides; systemic acquired resistance inducer
