Antifungal activity using medicinal plant extracts against pathogens of coffee tree

Abstract

Generally, the medicinal plants have antifungal substances that can be used for the plant protection against phytopathogens. The objective of this study was to know the efficiency of aqueous extracts from medicinal plants against the major etiological agents of coffee tree. The aqueous extracts used were extracted from bulbs of Allium sativum, leaves of Vernonia polysphaera, Cymbopogon citratus, Cymbopogon nardus, Cordia verbenacea, Eucalyptus citriodora, Ricinus communis, Azadirachta indica, Piper hispidinervum and flower buds of Syzygium aromaticum. The etiological agents considered for this study were Cercospora coffeicola, Colletotrichum gloeosporioides, Fusarium oxysporum, Phoma tarda, Rhizoctonia solani and Hemileia vastatrix. The screening for harmful extracts was done based on mycelial growth and conidial germination inhibition. All experiments performed were in vitro conditions. The inhibition of mycelial growth was performed mixing the extracts with the PDA. This mixture was poured in Petri dishes. On the center of the dishes was added one PDA disc with mycelium. It was incubated in a chamber set to 25ºC. The evaluation was done daily by measuring the mycelial growth. The germination assessment was also performed with Petri dishes containing agar-water medium at 2%. These were incubated at 25ºC for 24 hours. After this period the interruption of germination was performed using lactoglycerol. The experiments were conducted in a completely randomized design. The most effective plant extracts against the micelial growth and conidial germination were V. polysphaera, S. aromaticum and A. sativum. Keywords: Phoma tarda, Cercospora coffeicola, Colletotrichum gloeosporioides, Hemileia vastatrix, Phytopathology.RESUMO: Atividade antifúngica utilizando extratos de plantas medicinais contra fitopatógenos do cafeeiro. Geralmente, as plantas medicinais têm substâncias antifúngicas que podem ser utilizadas para a proteção das plantas contra fitopatógenos. O objetivo deste estudo foi conhecer a eficiência de extratos aquosos de plantas medicinais contra os principais agentes etiológicos do cafeeiro. Os extratos aquosos utilizados foram extraídos de bulbos de Allium sativum, folhas de Vernonia polysphaera, Cymbopogon citratus, Cymbopogon nardus, Cordia verbenacea, Eucalyptus citriodora, Ricinus communis, Azadirachta indica, Piper hispidinervum e botões florais de Syzygium aromaticum. Os agentes etiológicos considerados neste estudo foram Cercospora coffeicola, Colletotrichum gloeosporioides, Fusarium oxysporum, Phoma tarda, Rhizoctonia solani e Hemileia vastatrix. A triagem dos extratos foi realizada com base no crescimento micelial e na inibição da germinação de conídios. Todos os experimentos foram realizados em condições in vitro. A inibição do crescimento micelial foi realizada misturandose os extratos com PDA. Esta mistura foi vertida em placas de Petri. No centro das placas foi adicionado um disco de PDA com micélio. Incubou-se em câmara programada para 25°C. A avaliação foi feita diariamente através d...

Evaluation of Antifungal Potential of Allium Ampeloprasum Against Fungal Phytopathogens

“…Antifungal analysis of A. sativum extracts against different fungal pathogens of coffee tree shows that the A. ampeloprasum extracts can inhibit mycelial growth by 100% as well as also effectively preventing the germination of spores [4]. It is found that the mechanism of action, of A. ampeloprasum as an antifungal agent, is due to the competitive inhibition of sulfhydryl-containing enzymes by allicin and the inhibition of lipid biosynthesis leading to cell wall damage, as seen in the case of Candida albicans [9,21].…”

“…Many natural products obtained from plants having biocidal activity are considered as an alternate effective and eco-friendly source against phytopathogens [3]. Moreover, these natural products are usually cheaper than commercial fungicides and are easily accessible to farmers [4]. Allium species is recognized as an important genus of the Alliaceae family and well known for its biocidal properties [5].…”

Óleos essenciais e vegetais no controle in vitro de Colletotrichum gloeosporioides

“…), a menta (Mentha piperita L.) (Carnelossi et al, 2009;Sarmento-Brum et al, 2014;Bhuyan, et al, 2015), e o cravo da índia (Syzygium aromaticum (L.) Merr. & L. M. Perry) (Silva et al, 2014).…”

“…A inibição do crescimento dos fungos fitopatogênicos, por estes antimicrobianos naturais é devido às substâncias bioativas encontradas em plantas (Chiejina & Ukeh, 2012, Silva et al, 2014 (Ogbebor et al, 2007 A concentração inibitória mínima (CIM) dos óleos essenciais foi determinada seguindo os protocolos do CLSI (2008), utilizando-se o método de microdiluição em placas. Após incubação a 37ºC por cinco dias a CIM foi avaliada, sendo que a presença de células fúngicas viáveis nas concentrações não inibitórias foi determinada pela adição, em cada amostra, do corante 2,3,5 -Triphenyltetrazolium Chloride , no volume de 50 µL.…”

ANTIFUNGAL ACTIVITY OF Cirsium arvense EXTRACTS AGAINST PHYTOPATHOGENIC FUNGUS Macrophomina phaseolina

“…However, the plead for sustainable agriculture in an eco-friendly manner cannot be sustained with such health hazard chemicals (Oruc, 2010). An alternative strategy could be applied through the exploration of natural antimicrobial compounds from plant bark, stems, leaves, flowers and fruits (Ikram and Dawar, 2013;Silva et al, 2014;Javaid and Akhtar, 2015). These can act directly as pesticides or may provide structural lead for the development of pesticides (Kilani, 2006;Tapwal et al, 2011).…”