ABSTRACT
Strawberry and peach crops are of great economic and social importance, mainly due to the added value and income generation for small and medium producers in different regions of Brazil. Some fungal diseases can compromise the final profitability of production, such as those caused by Colletotrichum sp., Botrytis cinerea and Monilinia fructicola fungi. The control of these pathogens mainly occurs through fungicides, which has been generating concern for consumers, as well as biological imbalance and environmental contamination. The need for new alternatives for disease control has been leading to more research being conducted on essential oils. Our scientific questions were based on a compilation of experiments which revealed the efficiency of essential oils in disease control. With the purpose of evaluating the fungicidal activity of Aloysia citriodora, Cymbopogon winterianus, Lippia alba and Ocimum americanum essential oils on the control of fungi, such as Colletotrichum sp., Botrytis cinerea and Monilinia fructicola in vitro and in the post-harvest of fruits, this work was developed at the Federal University of Santa Maria, Frederico Westphalen county (Rio Grande do Sul state), Brazil, from 2016 to 2018. The following evaluations were done: (i) characterization of essential oil doses in vitro for controlling Colletotrichum sp., Botrytis cinerea and Monilinia fructicola fungi, and (ii) determination of the minimum inhibitory concentration (Ω, mL/L) of essential oils in post-harvest of strawberries and peaches. All essential oils have high fungicidal activity in vitro experiments. The A. citriodora, L. alba and O. americanum essential oils had a satisfactory effect for post-harvest controlling of Colletotrichum sp. C. winterianus and O. americanum. The essential oils promoted satisfactory post-harvest control of Botrytis cinerea in strawberries. All essential oils have high fungitoxicity against Monilinia fructicola in vitro and post-harvest, highlighting the greater efficiency of A. citriodora essential oil in peaches. The essential oils present high fungitoxicity for controlling diseases in strawberries and peaches, presenting high potential performance for formulating commercial fungicide.
Subject(s)
Food Microbiology , Fragaria/microbiology , Fungi/drug effects , Oils, Volatile/pharmacology , Prunus persica/microbiology , Antifungal Agents/pharmacology , Ascomycota/drug effects , Botrytis/drug effects , Brazil , Colletotrichum/drug effects , Fruit/microbiology , Plant Diseases/microbiology , Plant Diseases/prevention & control , Verbenaceae/chemistryABSTRACT
The use of highly toxic pesticides to control soil pathogens, such as Fusarium spp. and Sclerotinia sclerotiorum has generated concern, due to the irreversible impacts caused on the environment, in addition to selecting resistant isolates. In this way, essential oils appear as an efficient alternative in control of diseases. Facing the problem of soil pathogens control and high antimicrobial fungicide that essential oils present, this work aimed to evaluate the in vitro fungicidal potential of essential oils in control of Fusarium spp. and S. sclerotiorum. A completely randomized design, factorial scheme 2×4×8 was used, with two isolates (Fusarium spp. and S. sclerotiorum), four essential oils (Aloysia citriodora, Cymbopogon winterianus, Lippia alba and Ocimum americanum), eight essential oil concentrations (0.0; 0.2; 0.4; 0.6; 0.8; 1.0; 1.2 and 1.4 ?L·mL-1), and ten replicates. The essential oils inhibited mycelial growth of the fungi in different concentrations, being their potential justified by the presence of antifungal chemical compounds. Essential oils of A. citriodora, C. winterianus, L. alba and O. americanum present high fungicidal potential, being viable alternatives for formulation of commercial products, boosting the pesticides industry.(AU)
O uso de pesticidas com alta toxicidade para controlar patógenos do solo, como Fusarium spp. e Sclerotinia sclerotiorum, tem gerado preocupação, devido aos impactos irreversíveis causados no meio ambiente, além de selecionar isolados resistentes. Dessa forma, os óleos essenciais surgem como uma alternativa eficiente no controle de doenças. Diante da problemática de controle de patógenos do solo e alto potencial antimicrobiano que os óleos essenciais possuem, este trabalho teve como objetivo avaliar o potencial fungicida de óleos essenciais no controle de Fusarium spp. e S. sclerotiorum, in vitro. Utilizou-se um delineamento inteiramente randomizado, esquema fatorial 2×4×8, com dois isolados (Fusarium spp. e S. sclerotiorum), quatro óleos essenciais (Aloysia citriodora, Cymbopogon winterianus, Lippia alba e Ocimum americanum) e oito concentrações de óleo essencial (0,0; 0,2; 0,4; 0,6; 0,8; 1,0; 1,2 e 1,4 ?L·mL-1), com dez repetições. Os óleos essenciais inibiram o crescimento micelial dos fungos em diferentes concentrações, sendo seu potencial justificado pela presença de compostos químicos antifúngicos. Os óleos essenciais de A. citriodora, C. winterianus, L. alba e O. americanum apresentam alto potencial fungicida, sendo alternativas viáveis para formulação de produtos comerciais, impulsionando a indústria de agrotóxicos.(AU)
Subject(s)
Pesticides/toxicity , Pesticide Utilization , Oils, Volatile , Noxae , Ascomycota , Soil , Ocimum canum , Environment , Fusarium , Antifungal AgentsABSTRACT
O conhecimento da composição mineral dos grãos e da exportação de nutrientes pela cultura do painço é importante para aprimorar sua utilização e promover recomendações de adubação mais racionais. Portanto, o presente trabalho objetivou-se avaliar o teor de proteína e macronutrientes nos grãos e a exportação de macronutrientes pela cultura do painço, cv. AL Tibagi, submetida à diferentes doses e épocas de aplicação de N em cobertura. O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 4x2, constituído por quatro doses (0, 30, 60 e 120 kg ha-1 de N) e duas épocas de aplicação (14 e 28 dias após a emergência) do fertilizante nitrogenado (uréia) em cobertura, com quatro repetições. A aplicação de N em cobertura aumentou a produtividade de grãos e os teores de N e proteína bruta nos grãos da cultura do painço, porém, reduziu o teor de K. A adubação nitrogenada de cobertura aumentou a exportação de N, P, Ca, Mg e S pelos grãos da cultura do painço. A exportação de macronutrientes na cultura do painço teve em média a seguinte ordem: 28,1 kg ha-1 de N; 3,4 kg ha-1 de P; 2,1 kg ha-1 de Ca; 1,4 kg ha-1 de S; 0,9 kg ha-1 de K e 0,8 kg ha-1 de Mg.
Knowledge of the mineral composition of grain and export of nutrients by the proso millet is important to enhance their use and promote more rational fertilizer recommendations. This work aimed to evaluate the protein and nutrients in the grain and export of macronutrient by the proso millet, cv. AL Tibagi, submitted to different doses and times of nitrogen top-dressing application. The experimental design was randomized block design in a 4x2 factorial scheme, constituted by four doses (0, 30, 60, and 120 kg ha-1 of N) and two application times (14 and 28 days after emergency) of N fertilizer (urea) in top-dressing with four replications. Nitrogen top-dressing application increased grain yield and N content and protein in grains of proso millet, however, reduced the concentration of K. Nitrogen topdressing fertilization increased the export of N, P, Ca, Mg and S for the grains of proso millet. Proso millet exported an average of macronutrients in the following order: 28.1 kg ha-1 N; 3.4 kg ha-1 P; 2.1 kg ha-1 Ca; 1.4 kg ha-1 S, 0.9 kg ha-1 K and 0.8 kg ha-1 Mg.
