A pressão de seleção promovida por fungicidas na agricultura estimula mecanismos de variabilidade dos patógenos a desenvolver populações insensíveis a moléculas químicas. Objetivo deste trabalho foi caracterizar a sensibilidade de isolados de C. gloeosporioides a fungicidas in vitro. Oito isolados de C. gloeosporioides (COLL) pertencentes a Coleção Micológica do IFGoiano câmpus Urutaí foram testados in vitro e sua sensibilidade testada para os seguintes fungicidas: i) tiofanato metílico, ii) trifloxistrobina + tebuconazol, iii) piraclostrobina + epoxiconazol, vi) azoxistrobina + ciproconazol, nas concentrações de 0.1, 1, 10, 100 ppm (além do controle). O experimento inteiramente casualizado, em fatorial representado por : fator isolado [8], fator dosagem [5] e fator tipo de fungicidas [4], com duas repetições. O isolado de Colletotrichum oriundo de soja foi o que teve estatisticamente o maior diâmetro de colônia em relação aos demais isolados analisados. A mistura de fungicida trifloxistrobina + tebuconazol foi a que estatisticamente apresentou maior porcentagem de inibição, diferindo estatisticamente dos demais fungicidas analisados. De acordo com o critério adotado a maioria dos isolados adequaram-se na classe dos isolados intermediários, sendo detectado dentre os oito isolados nenhuma população ou isolado com comportamento de insensibilidade ou resistência aos fungicidas utilizados para controle, já que a 100 ppm não houve crescimento micelial de nenhum isolado. As maiores amplitudes de EC50 foram observadas para os fungicidas Trifloxistrobina+tebuconazol e Piraclostrobina+epoxiconazol, demonstrando que entre os isolados testados para esses dois fungicidas existe maior diversidade da sensibilidade a essas moléculas. Através desse trabalho podemos verificar a variabilidade de sensibilidade que isolados Colletotrichum gloesporioides podem apresentar perante as diferentes moléculas utilizadas comercialmente para seu controle.
Whilst Brazil is the fourth largest cotton producer globally, incidence of ramularia leaf spot (RLS) has decreased yield across all growing regions. In 2017-18 and 2018-19 growing seasons, ca. 300 fungal samples were collected from seven Brazilian states. Hyphal tip cultures were obtained for DNA extraction and amplification of partial sequences of the RNA polymerase II gene (RPB2), 28S rRNA, the ribosomal DNA internal transcribed spacers (ITS), actin (ACT), elongation factor (EF1-α) and histone H3 (HIS3) gene regions. Genetic diversity of the isolates was evaluated using fourteen molecular markers. Clade assignments based on the concatenated-sequence tree (RPB2, LSU, EF1-α, ITS, ACT, and HIS3) were identical to those in tree clades generated by RPB2-sequences, as well as in an RPB2 haplotype network, in an ISSR (TGTC)4 dendrogram, and based on morphological comparisons. In total, 252 out of 267 isolates were identified as Ramulariopsis pseudoglycines, indicating this species as the most widespread causal agent of cotton RLS in the Brazilian growing regions today. Validation of the ISSR (TGTC)4 primer as a tool to study the diversity and distribution of Ramulariopsis species will make it possible to carry out extensive RLS sampling studies worldwide.
– In Brazil has been stimulated the use of Jatropha curcas as an alternative for use in biodiesel. Anthracnose-of-jatropha is a frequent disease main in regions and seasons with hot and moisture weather. The objective of this study was to evaluate the effect of inoculum concentrations and pathogenicity of C. gloeosporioides in jatropha leaves. Fruits and leaves collected during the rainy season (Urutaí, GO) presenting leaf spot symptoms were taken to the laboratory for isolation and identification of the pathogen. In light microscope he observed that this was an isolated Colletotrichum sp. From this isolate two assays were performed: a) inoculating test mycelial disks on potted plants (treatments with and without injury); b) conidial suspensions were inoculated at concentrations of 103, 104, 105 and 106 conídios.mL-1 using the method of "detached leaves" (wounding treatments with and without injury). In the first assay the plants showed a latent period of 11 days with an average severity of 1 %. In the second trial in treated wounds showed the highest values of area under the disease progress curve (AUDPC) for concentrations of 105 conídios.mL-1 (2938.2 + 178.5) and 106 conídios.mL-1 ( 3685.2 + 347.5), statistically different from the others. And in no injury treatments, dilution 104, 105 and 106 conídios.mL-1 statistically equal AACPD values differing only in minor inoculated concentration. Through this work we can see the pathogenicity of C. gloeosporioides in jatropha and point the concentration of 106 conídios.mL-1 as ideal for testing and resistance studies jatropha anthracnose.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.