Antagonism of yeasts to Xanthomonas campestris pv. campestris on cabbage phylloplane in field

Abstract

Twenty yeast isolates, obtained from cabbage phylloplane, were evaluated for antagonistic activity against Xanthomonas campestris pv. campestris, in field. Plants of cabbage cv. 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%) was also calculated. Yeast isolates LR32, LR42 and LR19 showed, respectively, 72, 75 and 79% of DSR. These antagonists were tested in seven different application periods in relation to pathogen inoculation (T 1 =4 d before; T 2 =simultaneously; T 3 =4 d after; T 4 =4 d before + simultaneously; T 5 =4 d after + simultaneously; T 6 =4 d before + 4 d after; T 7 =4 d before + simultaneously + 4 d after). The highest DSRs were showed by LR42 (71%), LR42 (67%), LR35 (69%) and LR19 (68%) in the treatments T 7 , T 4 , T 5 and T 6 , which significantly differed from the others. The same yeast antagonists were also tested for black rot control using different cabbage cultivars (Fuyutoyo, Master-325, Matsukaze, Midori, Sekai I and Red Winner). The DSRs varied from 58 to 61%, and there was no significant difference among cultivars.

Antagonism of Bacillus species against Xanthomonas campestris pv. campestris and Pectobacterium carotovorum subsp. carotovorum

“…The black rot occurs more frequently in humid soils and temperatures ranging from 20 to 30°C, which are common in tropical and subtropical regions (Mariano et al, 2001). The symptoms are characterized by yellow V-shaped lesions that begin on the leaf marines and progress to the center through the vascular tissue, resulting, in general, the leaf necrosis (Assis et al, 1997).…”

Growth, sporulation and production of bioactive compounds by Bacillus subtilis R14

“…campestris in all application periods tested (Assis et al, 1996). When submitted to field tests, this isolate had its efficiency corroborated, reducing 73% of the disease on cabbage (Assis et al, 1997). The control of the bacterial fruit blotch was investigated in vivo by treating the infected yellow melon seeds with broths of B. subtilis R14 cultivation (Santos et al, 2006).…”

Evaluation of the potential yield and primary symptoms of Xanthomonas campestris pv. campestris infection in Asian vegetables grown in the Czech Republic

“…campestris (Xcc). Typical symptoms of this pathogen are necrotizing V-shaped lesions starting from the leaf edges and blackening vascular bundles of plants [6,7]. Testing for resistance to Xcc should form part of an assessment of how suitable it is to grow these species under given climatic conditions.…”