In Ontario, Canada, Fusarium graminearum Schwabe causes Gibberella ear rot (GER) in maize, resulting in the accumulation of mycotoxins, mainly deoxynivalenol (DON), DON-3-glucoside (DON-3G) and zearalenone (ZEN) in infected kernels. Fungicides can be an important tool for managing GER and DON and other Fusarium mycotoxins in maize. Until recently, all fungicides available to growers were triazoles, thus no resistance management strategy through fungicide use was possible. In this study, a novel carboxamide fungicide active ingredient (pydiflumetofen) was evaluated against conventional triazole fungicides and mixtures for: (1) effectiveness on mycotoxins (2) optimal application timing; and (3) efficacy of application, with and without an insecticide, under natural and inoculated-misted conditions. The best timing for fungicide application was at full silk, resulting in the highest reduction of GER symptoms and lowest accumulation of F. graminearum mycotoxins in harvested grain. DON and DON-3G concentrations were reduced by at least 50% with a fungicide application at full silk. Fungicide treatments did not affect fumonisin concentrations in grain. Pydiflumetofen (94 g active ingredients (AI)/ha) and fungicides containing pydiflumetofen (75-94 g AI/ha) were similar to standard triazole fungicides (prothioconazole at 200 g AI/ha and metconazole at 90 g AI/ha) for reducing GER and F. graminearum mycotoxins under misted-inoculated plots and commercial field conditions; as a result, we expect pydiflumetofen to be competitive with triazole-only chemistries in the marketplace, which should delay the onset of fungicide resistance.
Temperature and photoperiod have a direct effect on spore germination and, for Botrytis squamosa, there is scare information on this subject. Learning the biology of the causal agent has a great importance to understand the development of the disease in the field, as well to take control measures. With the aim of evaluating the influence of temperature and photoperiod on B. squamosa conidial germination, an experiment was conducted in a completely randomized design with four replicates. A 0.1-ml suspension of 1.65x105 conidia per ml was added and spread on Petri dishes containing 1% water-agar. The Petri dishes were placed in BOD incubators adjusted to 10, 15, 20, 25 and 30°C without light, and the percentage of germination of 100 conidia was evaluated under an optical microscope by measuring the germ tube after 24 hours of incubation. In a second moment, this experiment was repeated by incubating the spores at 23°C and photoperiods of 0, 6, 12, 18 and 24 hours, and by evaluating the percentage of germination after 24 hours. Results showed that the highest germination percentages can be obtained in the temperature range between 10 (79.75%) and 30°C (92.5%), and the optimum temperature for germination is 23°C. In relation to photoperiod, the highest germination percentage (94%) was obtained without light, which indicates that B. squamosa germination is favored by shorter periods of light. Thus, the information obtained on the biology of the causal agent of botrytis leaf blight allows better understand the epidemiology of this disease, and such results can be used to help develop a disease forecasting system.
In the Great Lakes region of North America, Gibberella ear rot (GER), caused by Fusarium graminearum, affects grain quality due to the accumulation of mycotoxins. GER severity is strongly influenced by environmental conditions; however, agronomic practices can also influence disease severity and mycotoxin accumulation. In this study, three separate small-plot experiments were conducted at Ridgetown, ON, Canada during 2019 and 2020 under an inoculated-misted system to determine Fusarium mycotoxin accumulation as affected by: (1) plant population density; (2) in-row-plant developmental variability; and (3) the effect of integrated Bt refuge genetics. In this study, DON concentrations were at least 49% higher in maize at 113,600 plants/ha compared to 79,000 plants/ha. Moreover, mycotoxin accumulation was higher in plants that were delayed developmentally in the crop row; total DON concentrations were at least 310% higher in late silked plants adjacent to early silked plants. Results of the plant population density and in-row-plant developmental variability suggest that the main driver for mycotoxin accumulation was stress induced by plant competition rather than environmental conditions; this highlights the importance of avoiding plant competitive stress as a strategy to reduce the risks of mycotoxin accumulation. In this study, there was no statistical difference in DON accumulation between the Bt component and the non-Bt component in each of the four hybrids tested; however, there was evidence that hybrids varied in susceptibility, including the Bt and non-Bt components that were paired commercially in a bag of seed maize. Reducing mycotoxins in maize requires integrated management, which includes agronomic considerations. These results indicate that mycotoxins are favoured with high plant populations and plant-to-plant variability in the row, especially in susceptible hybrids.
RESUMO A produção de mudas de cebola na região do Alto Vale do Itajaí, SC ocorre predominantemente através de canteiros, onde as plantas ficam expostas aos fatores bióticos e abióticos que influenciam diretamente na sanidade foliar e no seu rendimento. Diante disso, o objetivo deste trabalho foi avaliar a influência da cobertura dos canteiros com túnel baixo sobre o rendimento e a intensidade de doenças foliares. Os experimentos foram realizados nos anos de 2012 e 2013 no Instituto Federal Catarinense, Campus de Rio do Sul, SC. Os tratamentos foram com e sem o uso de túnel baixo. O delineamento utilizado foi o de blocos casualizados com quatro repetições e dez plantas avaliadas em cada repetição. Os dados foram submetidos à análise de variância pelo teste F e se significativos comparados pelo teste de Tukey 5%. A massa fresca da parte aérea com o uso do túnel foram superiores em relação ao sistema convencional em 127,38% e 125,40% no ano de 2012 e 2013 respectivamente. Em 2012 ocorreu uma diferença de 42,88% na área abaixo da curva de progresso da doença (AACPD) da queima das pontas e no ano de 2013 uma diferença de 87,27% e 85% na AACPD e severidade final respectivamente para o míldio. As mudas produzidas em canteiros com túnel baixo apresentaram superioridade no rendimento e sanidade foliar em relação às obtidas no sistema de produção convencional.
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.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.