ABSTRACT
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
In vitropropagation increases the supply and commercialisation of products of interest. For this, optimising the growing conditions and the composition of the culture medium is crucial to benefit the full development of the plants. Thus, the objective was to evaluate the in vitropropagation of Aloysia triphyllaon different culture media, with varying agar and sucrose concentrations. The experiment was conducted as a completely randomised design, 3×3×3 factorial scheme, with three culture media (MS, JADS and WPM), three sucrose concentrations (8, 10 and 12 g L-1) and three agar concentrations (15, 30 and 45 g L-1), with three replicates each and experimental units composed of one plant per replicate. After 25 days of cultivation, the fresh and dry mass of the plants, numbers of leaves, numbers of nodes, plant lengths, numbers of oxidised leaves, hyperhydricity and acclimatization percentages were evaluated. The WPM medium resulted in a reduced fresh mass, reflecting in the low hyperhydricity observed in the explants, and favoured the acclimatization of the plants. Thus, the WPM medium with sucrose (15 g L-1) and agar (12 g L-1) is recommended as the medium most suitable for the in vitroregeneration of Aloysia triphylla.