Abstract Potato scab is one of the main diseases affecting potato tubers during their development, causing great commercial damage to farmers. The use of some antagonistic microorganisms has been shown as a viable alternative to phytosanitary control of several crops. However, this work aimed to verify in vitro effects of microorganisms antagonistic against phytopathogenic Streptomyces sp. and in vivo treatment of scab in potato tubers. Trichoderma longibrachiatum; Trichoderma harzianum; Pochonia clamydosporia; Bacillus subtilis (except for in vivo test); Bacillus subtilis + Trichoderma longibrachiatum, and Bacillus subtilis + Enterococcus faecium were tested for in vitro growth inhibition of Streptomyces via microorganism radial pairing test, with both volatile and non-volatile metabolites. In parallel, the antagonistic microorganisms were tested in vivo in protected environments by cultivating potato plants in pots with soil contaminated with Streptomyces sp., then evaluating the number of injured tubers, injured area, severity index, production losses and the frequency of tubers by lesion type. The results indicate major in vitro inhibition of Streptomyces sp. by Trichoderma longibrachiatum, Trichoderma harzianum, and Bacillus subtilis + Enterococcus faecium under the antagonism (48 - 80%) and antibiosis tests, as well as a major reduction of tuber lesions size (34 - 60%), severity index, and production losses in the in vivo test.

RESUMO O tomate é um importante componente da dieta humana, pois é rico em sais minerais e compostos antioxidante que sequestram os radicais livres presentes nas células do organismo, evitando vários distúrbios na saúde humana. O presente trabalho teve o objetivo de avaliar os efeitos de fontes e doses de nitrogênio sobre a capacidade antioxidante e a qualidade físico-química dos frutos do tomateiro. O experimento foi realizado na cidade de Vitória da conquista - BA, no campo experimental da Universidade Estadual do Sudoeste da Bahia. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições em esquema fatorial 3 × 3 + 1 (testemunha), totalizando 40 parcelas. Os tratamentos foram compostos por três fontes de Nitrogênio (nitrato de cálcio, ureia e sulfato de amônio) e três doses (140, 280 e 420 kg ha-1). Após a colheita foram avaliados os atributos da qualidade do fruto: firmeza, pH, acidez titulável, sólidos solúveis, ratio, ácido ascórbico, DPPH, compostos fenólicos, carotenoides, flavonóides. Os níveis crescentes de N influenciaram negativamente nos conteúdos de acidez titulável, por outro lado, proporcionou aumento na relação SS/AT. Os incrementos de N também reduziram o conteúdo de compostos bioativos, exceto carotenoide, consequentemente prejudicou a atividade antioxidante.

ABSTRACT Tomatoes are an important component of the human diet because they are rich in minerals and antioxidants that sequester free radicals in cells, preventing various disorders that affect human health. Here, we aimed to evaluate the effects of different nitrogen sources and concentrations on antioxidant capacity and physical and chemical quality of tomato fruit. The experiment was conducted in Vitória da Conquista, state of Bahia, Brazil, in the experimental field of Universidade Estadual do Sudoeste da Bahia. The experimental setup included a randomized block design with four replicates in a factorial layout of 3 × 3 + 1 (control), for a total of 40 plots. The three treatments comprised different nitrogen sources (calcium nitrate, urea, and ammonium sulfate), applied in three doses (140, 280, and 420 kg ha-1). We evaluated firmness, pH, titratable acidity - TA, soluble solid - SS, SS/TA ratio, ascorbic acid, carotenoids, flavonoids, phenolic compounds and DPPH inhibition, were evaluated after samples were harvested. However, increasing concentrations of N adversely affected the acidity and led to an increase in the SS/TA ratio. Increasing the N concentration also reduced the content of bioactive compounds. excluding carotenoids, which consequently impaired antioxidant activity.

Diversas alternativas vêm sendo estudadas e utilizadas no controle de doenças de plantas, no intuito de suprir as necessidades dos produtores e consumidores no desejo de reduzir o uso de defensivos agrícolas. Assim, o objetivo deste trabalho foi avaliar a atividade de extratos vegetais de Azadirachta indica A. Juss., Anonna muricata L. e de Lippia alba (Mill) N. E. Brown. no controle de Colletotrichum gloeosporioides Penz. in vitro. O experimento foi conduzido na Universidade Estadual do Sudoeste da Bahia, Câmpus de Vitória da Conquista, Bahia, Brasil. Extratos aquosos de folhas de graviola e erva-cidreira, e extratos aquosos de sementes de nim e graviola foram usados visando à inibição do crescimento micelial do patógeno causador da antracnose em frutos de mamão. A atividade antifúngica dos extratos foi mensurada mediante a medição do crescimento micelial das culturas. O delineamento adotado foi o DIC em esquema fatorial (3x3x3), com quatro repetições, nos dois experimentos. Os resultados obtidos indicam maior inibição ao crescimento micelial do patógeno com o uso dos extratos de folhas de erva-cidreira e de sementes de graviola.

Several alternatives have been studied and used in the control of plant diseases, in order to achieve the needs of producers and consumers desiring to reduce the use of pesticides. Thus, the objective of this study was evaluating the activity of plant extracts Azadirachta indica A Juss., Annona muricata L. and Lippia alba (Mill) N. E. Brown. in controlling of Colletotrichum gloeosporioides Penz. in vitro. The experiment was conducted in State University of Southwest Bahia, campus of Vitoria da Conquista city, State of Bahia, Brazil. Aqueous extracts of leaves of soursop leaves and lemongrass, and aqueous extracts of neem seeds and soursop were used to inhibit mycelial growth of pathogen of anthracnose from papaya fruits. The antifungal activity of the extracts was determined by measuring the mycelial growth of cutures. The experimental design was CRD in factorial (3x3x3) with four repetitions in both experiments. The results suggested inhibitory action of the leaf extract of lemongrass and the seed extract of soursop.