Antagonism of Yeasts to Xanthomonas Campestris PV. Campestris on Cabbage Phylloplane in field

Twenty yeast isolates, obtained from cabbage phylloplane, were evaluated for antagonistic activity against Xanthomonas campestris pv. campestris, in field. Plants of cabbage ev. Midori were pulverized simultaneously with suspensions of antagonists and pathogen. After 10 days, plants were evaluated through percentage of foliar area with lesions. Percentage of disease severity reduction (DSR per cent) was also calculated. Yeast isolates LR32, LR42 and LR19 showed, respectively, 72, 75 and 79 (per cent) of DSR. These antagonists were tested in seven different application periods in relation to pathogen inoculation (T1=4 d before; T2=simultaneously; T3=4 d after; T4=4 d before + simultaneously; T5=4 d after + simultaneously; T6=4 d before + 4 d after; T7=4 d before + simultaneously + 4 d after). The highest DSRs were showed by LR42 (71 per cent), LR42 (67 per cent), LR35 (69 per cent) and LR19 (68 per cent) in the treatments T7, T4, T5, and T6, which significantly differed from the others. The same yeast antagonists were also tested for back rot control using different cabbage cultivars (Fuyutoyo, Master-325, Matsukaze, Midori, Sekai I and Red Winner). The DSRs varied from 58 to 61 (per cent), and there was no significant difference among cultivars

Biocontrole pós-colheita da podridäo de Lasiodiplodia em frutos de manga por leveduras saprofíticas / Postharvest biocontrol of Lasiodiploidia rot of mango fruits by saprophytic yeasts

Among eigtheen yeast isolates studied as potential agents for biocontrol of stem-end rot on mango fruits caused by Lasiodiplodia theobromae, five were selected for testing in relation to three pathogen concentrations (1x10ü, 1x10 elevada à quarta and 1x10 elevada à quinta conidia/ml). The isolate LM-5 (Candida maritima) showed high control level at all pathogen concentrations. When tested against five pathogen isolates, LM-5 again demonstrated high control efficiency, and at in vitro test, highlyinhibited L.theobromae spore germination. The isolate LM-5 demonstrated great potential as agent for postharvest biocontrol of mango rot

Bacillus subtilis as a potential biocontrol agent of the northern leaf blight of corn

Quatro isolados de Bacillus subtilis (AP-3, AP-420, IF-36 e IF-82) foram estudados como agentes potenciais para o biocotrole da queima das folhas do milho, causada por Exserohilum turcicum. Em condiçöes de casa-de-vegetaçäo os isolados bacterianos demonstraram boa eficiência para o biocontrole. Considerando a média de 3 períodos de aplicaçäo, o isolado AP-420 foi o mais eficiente. A aplicaçäo dos antagonistas simultaneamente com a inoculaçäo de E. turcicum apresentou os melhores resultados. Em condiçöes de laboratório as bactérias produziram metabólitos extracelulares, näo-voláteis e difusíveis que inibiram o crescimento micelial e a germinaçäo de conídios de E. turcicum