Propolis for the control of powdery mildew and the induction of phytoalexins in cucumber

Abstract

Due to its antimicrobial properties propolis has been utilised by man for millennia, however, only recently has its use as an agricultural antimicrobial agent been tested. The capacity of this product to activate plant defence mechanisms is highly promising, due to the large number of substances in its composition. Therefore, the objective of this study was to evaluate the effect of different concentrations and application times of ethanol extracts of propolis (EEP) on powdery mildew (Podosphaera fuliginea) in cucumber crops, to establish the most suitable method for control and whether or not there is potential to induce plant defence mechanisms. The experiment was conducted in pots in a greenhouse. A completely randomised experimental design was employed, using a 6x3 factorial consisting of six concentrations (0; 0.5; 1; 2; 4 and 8%) and three EEP application times (24 hours before pathogen inoculation, 24 hours after pathogen inoculation and at the onset of first symptoms of the disease), replicated four times. Evaluations for disease incidence and severity were made weekly. The experiment was repeated for a second crop, following the same methodology established in the first. We also evaluated the effect of different EEP concentrations on the activation of plant defence mechanisms, through the induction of phytoalexins in soybean (Glycine max) cotyledons. A significant interaction was observed between the factors (application time x concentration) for disease incidence. For the area under the disease progress curve (AUDPC) for severity there was no interaction observed between the factors, however, we observed significant differences for the two factors separately. The AUDPC for incidence was less for the application 24 hours after pathogen inoculation, principally at the highest concentration. The 8% concentration of EEP controlled disease severity by 31.33 and 43.68% for the first and second crops, respectively. The application of the concentrations 24 hours before and 24 hours after pathogen inoculation showed less AUDPC for severity, but this difference was not significant for either crop. The EEP induced increasing phytoalexin levels in soybean cotyledons as the applied EEP concentration increased. Ethanol extracts of propolis could have potential for the control of powdery mildew, principally in cucumbers, through the preventive application of an 8% concentration.

New emerging fields of application of propolis

“…This remarkable combination makes it an excellent candidate for preserving different foods. Successful experiments have been performed for utilization of propolis extracts in the preservation of numerous products: fruit juices [62][63][64][65], fruits [68][69][70][71][72][73][74][75][76][77], vegetables [78][79][80][81][82][83][84][85], eggs [86][87][88][89][90][91], meat and fish products [92][93][94][95][96][97][98][99][100] (Table 2). This field of application of propolis is rapidly growing, as indicated by the growing number of publications.…”

“…Hawaiiana) Ethanol extract Llanta Azul apiary, Zaragoza (Antioquia -Colombia) [77] Vegetables Rice (Oryza sativa, var. hinohikari) Absolute ethanol, methylene chloride and hexane extracts Brazilian green propolis [78] Carrot (minimally processed) 25% Water and alcohol extracts Brazilian green propolis [79] Lettuce Ethanol extract Bragança, Portugal [80] Cucumber 70% Ethanol extracts Pato Branco (PR), Brazil [81] Beans, carrots against white rot disease Alcohol extract Iraq [82] Mixed vegetables for soup Propolis extract Argentina [83] Celery, leek and butternut squash (minimally processed) Ethanolic extract; standardized to 10% propolis extract Mendoza province, Argentina [84] Chilli (Capsicum annuum L.) Ethanol extract Brazilian green propolis [85] Eggs Eggs quality during storage 70% Ethanol extract Hatay province, Turkey [86,87] Japanese quail eggs 70% Ethanol extract Hatay province, Turkey [88][89][90] Hens eggs Ethanol extract Parana state, Brazil, [91] Meat products Fresh oriental sausage 95% Ethanol extract Cairo, Egypt [92] Sausages 96% Ethanol extract Boyacá, Colombia [93] Fermented meat sausage "Alheira" 95 % ethanol Vila Franca, Viana do Castelo, Portugal [94] Beef patties Commercial ethanol extracts Sonora, Mexico, poplar type [95] Poultry meat product-cured cooked ham 96% Ethanol extract Slovakia [96] Fish products Nile tilapia (Oreochromis niloticus) fillets, frozen storage Water extract Egypt [97] Cachama fish (Piaractus brachypomus) fillets (refrigeration) 96% Ethanol extract Boyacá, Colombia [98] Fresh fish burgers 70% Ethanol extract La California, LI, Italy [99] Fresh shibuta (Barbus grypus) fillets Water extract Fanus Natural Company, Trabzon, Turkey [100] Others Milk protein concentrate (diary beverages) 94 % Ethanol extract Water extract Canada [101] Food packaging Chitosan-propolis coated polypropylene films 80% Ethanol extract Konya region, Turkey. [102] Antimicrobial edible coating of Bell Pepper 95% Ethanol extract China [103] Active film with antimicrobial effect, reduces oxidation of butter during storage 70% Ethanol extract Brazilian red propolis …”

Exogenous Application of Foliar Salicylic Acid and Propolis Enhances Antioxidant Defenses and Growth Parameters in Tomato Plants

“…In our experiment, propolis and salicylic acid have been proved to have a vital role in fasten maturity in tomato plants, and these results are confirmed by other studies [ 8 , 29 ]. Specifically, for propolis, it was argued that it does not increase the early yield directly, but preserves the fruits by forming a protective layer against different types of microbes, especially fungi that affect the fruits of tomatoes greatly and lead to a high loss of young fruits [ 38 , 39 ].…”

Actividad antifúngica de extractos etanólicos de propóleo contra Mycosphaerella fijiensis: un estudio in vitro

“…Para ello, se desarrolló una curva estándar de ácido gálico (0,10,20,40,60,90 (Paschos et al, 2015), por lo tanto, se estableció el control positivo para conocer este efecto en M. fijiensis, a pesar de que las inhibiciones fueron calculadas en función del control negativo. Las concentraciones de eep evaluadas fueron: 0, 1.25, 2.5, 5 y 10% (v/v), las cuales fueron seleccionadas con base a estudios previos de actividad antifúngica (Pineda et al, 2010;Guginski-Piva et al, 2015). Se emplearon cinco repeticiones por concentración y control evaluado.…”