1,895 research outputs found
Staley, Roberta
No full textcurrentAcademic Biography
BA (University of Calgary)
Diploma Journalism (Grant MacEwan)
MA Liberal Studies (Simon Fraser University)
Roberta Staley is an author, a magazine editor and writer, and a documentary filmmaker who has reported from such places as Afghanistan, Papua New Guinea, Kenya, El Salvador, Haiti, Colombia, Cambodia, South Africa, Israel, and New Zealand. She currently edits Enterprise magazine, and is a contributor to BC Business, the South China Morning Post Magazine, Ms. Magazine, Trek, the Canadian Chemical News, Corporate Knights, and Sculpture, among others. She is also a columnist for Just for Canadian Doctors/Dentists magazines. Roberta has published her first book, titled Voice of rebellion : how Mozhdah Jamalzadah brought hope to Afghanistan. It is a biography of Afghan-Canadian human rights activist Mozhdah Jamalzadah
Algae and cyanobacteria: prospects and challenges for plant disease management
No full textThe purpose of this Special Issue on “"Algae and cyanobacteria: prospects and challenges for plant disease management” is to present the latest scientific findings dealing with various aspects of potential application of macro-and micro-algae and cyanobacteria and their bioactive compounds against pre and post-harvest diseases, and their impact on plant and fruit physiology and biochemistry that may be related to plant resistance against biotic stresses
Biological control with a fungus called Beauveria bassiana
No full textSeveral commercial biological products are based on fungal microorganisms that are antagonistic of insects and fungal pathogens causing severe damage of agricultural plants.
Beauveria bassiana is the most wide-spread entomopathogenic fungus, component of several commercial products. This fungus parasitizes a wide range of noxious pests for agricultural plants such as the greenhouse whitefly (T. vaporariorum), different aphid species (Aphis fabae, Macrosiphum euphorbiae, Chaetosiphon fragaefolii), thrips (Frankliniella occidentalis and Thrips tabaci) and spider mites (Tetranychus urticae). When spores of B. bassiana come in contact with the skin of a susceptible insect, they penetrate its body, grow inside and kill the insect within few days. Finally, a white mould comes out from the cadaver and produces new spores that can colonize others hosts.
Beauveria bassiana based products have not a preharvest interval (PHI), any harmful effects on human or animal health, on groundwater or they have not any unacceptable influence on the environment. Furthermore, no effects of B. bassiana on bees (Apis mellifera) or other pollinators have been observed and the fact that bee vectoring is used to apply this strain would indicate a low risk to bees and other pollinators, making B. bassiana a useful tool in pests management strategies
Defense response against postharvest pathogens in hot water treated apples
No full textHot water treatment (HWT) has been demonstrated to be a safe and effective method to control postharvest diseases. In the present study, the effect of HWT (45 °C for 10 min) was investigated on the response of apple fruit against Botrytis cinerea, Colletotrichum acutatum and Neofabraea vagabunda infections. In vivo experiments were conducted with apples treated with HW and then inoculated with pathogen spore suspensions 0, 3, 6 and 24 h after the treatment. In vitro experiments were carried out in order to investigate the HWT effect on the pathogenesis enzyme activities of the three pathogens. These assays were conducted with the crude protein extracts (CPEs) derived from the hot water treated apples. A significant reduction of rot incidence was observed in fruit inoculated at 6 h (B. cinerea 22.7% and C. acutatum 11.0%) and 3 h (N. vagabunda 68.8%) after HWT with respect to the controls (22.0, 18.5 and 19.67 mm, respectively). CPEs extracted from hot water treated fruit inoculated at 6 h and 3 h showed the highest conidia germination inhibition (B. cinerea 85.6%; C. acutatum 52.7% and N. vagabunda 83.1%) with respect to the controls (74.0, 71.0 and 90.3% of conidia germination, respectively). A significant reduction of pathogenesis enzyme activities of the three pathogens was detected when pathogens were exposed to CPEs derived from hot water treated apples. The results showed that HWT can stimulate a defense response on apple against some postharvest pathogens
Algae and Cyanobacteria as Biocontrol Agents of Fungal Plant Pathogens
No full textAbstract: Since long time, algae are used in agriculture as soil amendment for their
beneficial effects on plant health and productivity. In fact, algae contain several
molecules such as plant growth hormones (cytokinins, auxins, abscisic and
gibberellic acid), polysaccharides, betaines and micronutrients. The research on
algae, their compounds and their effects on plants have started in the middle 1950s
and brought to the formulations of liquid products containing extracts with compounds
readily available for plants. The algae extracts, besides having effects on
plant growth, have demonstrated to improve plant resistance to both abiotic and
biotic stresses. Among biotic stresses, algae showed antifungal activity against
different pathogens especially of horticultural plants. From the middle of last
century, plant management has always been dependent from the market demand
that required growing quantity of ‘perfect’ fruits and vegetables over the year. In this
scenario, the chemical industry of fertilizers and pesticides developed new products
that have been used for years. In particular, pesticides have represented the base of
the management of fungal plant pathogens. During the last decades, the use of both
pesticides and chemical fertilizers has represented a serious risk for human health
and brought disorder of ecosystem equilibrium. Consequently, algae for their
biostimulant and antifungal effects may be considered useful tools to reduce the
input of chemicals in integrated pest management strategies. In line with these
strategies, the European Regulation EC 1107/2009, concerning the placing of
plant protection products on the market and repealing Council Directives 79/117/
EEC and 91/414/EEC, recommends that priority should be given to non-chemical
and natural alternatives wherever possible
Special Issue “Sustainable Control Strategies of Plant Pathogens in Horticulture”
No full textEuropean Regulation No [...
Use of algae in strawberry management
No full textIn agriculture, extracts from algae are used for their stimulant effects on plant vigor and productivity but little is known on their effect against fungal pathogens. However, the recent EU restriction on synthetic pesticides made the management of fungal plant pathogens difficult and greatly stimulated the research of alternative solutions to chemicals. Applications of extracts from algae can help limit disease spread in several crops and the development effective alternatives to chemical treatment in crop protection and nutrition management. In particular, for strawberry, the management of a number of serious diseases in open field and greenhouse in soil or soilless cultivation has become difficult due to recent restrictions in agrochemical use and the lack of effective alternatives. This review provides an overview of the most recent findings on the potential use of extracts of algae for strawberry management, concerning both their biostimulant effects and antifungal properties against pathogens. The existing reports on this topic show the strong potential of algae extracts application on plants both as biostimulants and bioprotectants against fungal pathogens. Further investigation is needed to fully uncover the interesting and exploitable antifungal properties of extracts from algae and to clarify the mechanism of action of extracts and singular components against pathogens
Sustainable Control Strategies of Plant Pathogens in Horticulture
No full textThe purpose of this Special Issue, “Sustainable Control Strategies of Plant Pathogens in Horticulture”, is to present the recent findings and future perspectives on the use of natural substances (i.e., plant extracts or molecules), microorganisms, plant-induced gene silencing that targets specific pathogens, organic cultivation systems and integrated pest management and any other means that can reduce the input of synthetic pesticides in the environment
Biocontrol ability of Trichoderma harzianum strain T22 against Fusarium wilt disease on water-stressed lettuce plants
No full textThe control ability of Trichoderma harzianum strain T22 against Fusarium wilt of lettuce caused by Fusarium oxysporum f.sp. lactucae strain 365.07 was studied through mesocosm assays under extreme soil water content available for plants (-0.5 and -0.03 MPa).T22 was applied to nursery substrate at seeding, and to mesocosm soil at transplant of seedlings artficially infected by the pathogen. T22 decreased disease severity in comparison to infected controls by 57 and 78% in dry and wet conditions, respectively. Plant biomass was increased by T22 under both moisture levels. T22 colony growth, spore germination and antagonism to the pathogen were investigated under different water potential ( -0.03, -0.1, -0.5, -1.0, -2.0, -7.0 and -14.0 MPa) on minimal agar medium. All these parameters were influenced by water potential. However, they were similar at the same MPa values tested in the mesocosm assays.Our results provide evidence that T. harzianum strain T22 could be effective to control wilt disease caused by F. oxysporum f.sp. lactucae strain 365.07 under extreme soil moisture regimes already present in Italy, and susceptible to become more frequent in the near future
Potential for biocontrol of Pleurotus ostreatus green mould disease by Aureobasidium pullulans De Bary (Arnaud)
No full textPleurotus ostreatus, commonly known as “oyster mushroom”, is an edible fungus economically important worldwide. The green mould, caused by Trichoderma pleuroti and T. pleuroticola, is a very important fungal disease, and it is commonly controlled by the use of fungicides. The yeast-like fungus Aureobasidium pullulans is a biocontrol agent naturally found throughout a wide range of habitats. The effect of A. pullulans L1 and L8 strains on P. ostreatus, T. pleuroti and T. pleuroticola was studied in in vitro assays. Both yeast strains resulted compatible with P. ostreatus growth, and effective in reducing the T. pleuroticola and T. pleuroti colony growth. The inhibitory effect of L1 and L8 was similar in the majority of the Trichoderma-A. pullulans combinations on agar plates. Both strains were more efficient than Trichoderma in substrate colonization, and produced volatile and nonvolatile metabolites which reduced Trichoderma growth. When the activity of L1 and L8 was tested against the green mould disease of P. ostreatus under controlled conditions similar to those of a mushroom farm, only L8 was effective in controlling the disease. It showed an effect similar to that of the fungicide prochloraz against T. pleuroticola, the less aggressive pathogen, and lower than that of the fungicide against T. pleuroti, the most aggressive. The antagonism was the result of mechanisms like antibiosis and competition for space and nutrients, whereas the direct attachment of A. pullulans with hyphae of the pathogens did not play a role
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