Genetic diversity and pathogenicity of the grey mould fungus Botrytis

Genetic diversity and pathogenicity of the grey mould fungus Botrytis Botrytis spp., causes pre- and postharvest decay on strawberry crops. Botrytis spp. isolates from several German strawberry-growing fields, which received several fungicide treatments against Botrytis per season, were analyzed to determine their sensitivity against botryticides.Universidad de Malaga. Campus de Excelencia Internacional Andalucia Tec

Designing strategies to control grey mould in strawberry cultivation using decision support systems

Grey mould is one of the major diseases in strawberry cultivation. Fungicides to control Botrytis cinerea are applied frequently during flowering and sometimes at harvest. Reduction of pesticide use is one of the major aims of the Dutch government. Implementation of a Decision Support System (DSS) helps to achieve this goal. Pin point timing of fungicide application can possibly improve the efficacy of the treatment and reduce the number of spray applications. Predicted weather data to forecast infection risks are used by most DSS’s. However in strawberry cultivation irrigation is a daily practice. The effect of overhead irrigation on the Botrytis infection risk is unknown. This is one of the reasons that strawberry growers infrequently use DSS’s. Therefore adaptation of the model to agricultural management is necessary. Under low disease pressure DSS BoWaS controlled Botrytis fruit rot 62% better then routine applications of fungicides, with a 50% reduction of fungicide input. Adding an irrigation or a disease pressure sub-routine did not improve the model under low disease pressure. BoWaS based on disease pressure and weather resulted in better control of grey mould then the weather based BoWaS, under high disease pressure. Adding an irrigation rule did not improve the model further. Using the modified BoWaS reduced fungicide input with 36% compared to routine applications with the same efficacy

PECTOPLATE: the simultaneous phenotyping of pectin methylesterases, pectinases and oligogalacturonides in plants during biotic stresses

Degradation of pectin, a major component of plant cell wall, is important for fungal necrotrophs to achieve a successful infection. The activities of pectin methylesterases (PMEs) from both plants and pathogens and the degree and pattern of pectin methylesterification are critical for the outcome of plant–pathogen interaction. Partial degradation of pectin by pectin degrading enzymes releases oligogalacturonides (OGs), elicitors of plant defense responses. Few analytical techniques are available to monitor pectin methylesterification-modulating machineries and OGs produced during plant pathogen interaction. In the present study, ruthenium red is presented as useful dye to monitor both Botrytis cinerea mycelium growth and the induction of PME activity in plant tissue during fungal infection. Moreover a simple, inexpensive and sensitive method, named PECTOPLATE, is proposed that allows a simultaneous phenotyping of PME and pectinase activities expressed during pathogen infection and of pectinase potential in generating OGs. The results in the manuscript also indicate that PME inhibitors can be used in PECTOPLATE as a tool to discriminate the activities of plant PMEs from those of pathogen PMEs expressed during pathogenesis

Gliocladium catenulatum as an antagonist against grey mould on strawberry

Gliocladium catenulatum gave excellent control of Botrytis on strawberry in several field trials in Finland

Development of disease control strategies for organically grown field vegetables (DOVE) (OF0168)

This is the final report of Defra project OF0168 (DOVE). The attached main report starts with a more detailed and comprehensive Executive Summary, from which this text has been extracted. This project aimed to improve understanding and awareness of diseases in organic field vegetables. Diseases pose a threat to both quality and yield, and both must be managed if organic production is to expand and remain sustainable. Objective 1. To review the significance of diseases in organically grown field vegetables and the potential effectiveness of current control strategies when the scale of production is increased. Objective 2. To evaluate novel techniques and strategies for control of diseases in organically grown field vegetables Objective 3. To monitor disease development in organic crops in relation to rotation and size of enterprise. Objective 4. To update, produce and publicise advisory literature for disease control in organic field vegetables. Literature review The philosophy of disease control in organic systems was reviewed together with recent literature on diseases and disease control in organic field vegetables. A wider literature on disease control in conventional agriculture and horticulture was also considered in order to provide novel approaches for organic producers. Novel approaches The benefits of using wider plant spacing and mulches of paper or black, red or blue polythene for control of lettuce diseases was investigated in two replicated field experiments on cv. Saladin in 1999. Lettuce variety mixtures were used to investigate their value for control of downy mildew. Mixtures often have positive effects in addition against pests, weeds and abiotic stress. Glasshouse experiments with foliar spray treatments were carried out to determine the spectrum of activity of a range of organic treatments against lettuce downy mildew, grey mould of lettuce and dark leaf spot of brassicas. All treatments gave significant control of lettuce downy mildew and dark leaf spot, but none (except the conventional standard) showed activity against grey mould. Field evaluation of foliar treatments was carried out in 2000 and 2001. It would appear that some organic treatments can provide effective control of foliar diseases, but they need to be used as protectant sprays with a short interval between treatments. Soil amendments with green crop residues, composts, manures and other treatments were evaluated in glasshouse pot experiments against various soil-borne diseases with mixed results. Disease monitoring Disease observations were made on 5 organic farms selected to provide different scales of production and contrasting regional differences. The results provide new information to suggest that larger scale production is more prone to disease problems. This observation is consistent with other epidemiological studies, including the mixture effect, which suggest that increasing the diversity of potential disease hosts per unit area tends to reduce the probability of infection. The presence of the weed parasite spores and of semiochemicals released from the weeds could have some influence in restricting disease development in crops through induction of resistance. Growers reported that potato blight was the most frequent problem each year during 1999-2001, followed by downy mildews on onions, brassica seedlings and lettuce, celery leaf spot and leek rust. Conclusions Diseases are common in organic vegetable crops, but severe infection leading to significant losses of yield or quality affected few crops (11%). Seed-borne diseases are important and availability of healthy seed would reduce losses in vegetables. Soil-borne diseases continue to trouble organic growers and can be managed through rotation or avoiding badly infested areas. Organic growers can exploit genetic diversity through cultivar and species mixtures, but development and guidance is required to develop practical systems. Disease management using organic conditioners, biological control agents and soil amendments merit investigation in farm-scale experiments. Key components of disease management strategies for organic vegetables have been made available to growers in a booklet produced as part of this project

Controle da podridão cinzenta da maçã por produtos naturais biologicamente ativos

Indexación: Web of Science; ScieloBiorend SC (chitosan), BC-1000 EC (grapefruit extract plus bioflavonoids) and ECO-100 SC (bioflavonoids plus organic acids, citric phytoalexins, fatty acids, glycerides and sugars), respectively, suppressed grey rot of apple caused by B. cinerea by 80.1%, 79.0% and 76.5% when used as post-harvest treatments under controlled conditions. When applied as combined pre- and post-harvest treatments Biorend SC inhibited fruit rot by 49.9 %, while BC-1000 EC and ECO-100 SC were ineffective. None of the products inhibited fruit rot when applied as pre-harvest treatments under controlled conditions or as post-harvest treatments under commercial conditions. The algal polysaccharide ulvan used in post-harvest treatments suppressed grey rot by 56.0% under controlled conditions, but had no inhibitory effect on combined pre- and post-harvest treatments. The inability of products to activate defense mechanisms (chitinase and peroxidase) of fruits was consistent with the unsuccessful control of rot by pre-harvest treatment. The results suggest that the natural products used have potential for use in integrated management of Botrytis rot when applied after harvest.Biorend SC (quitosana), BC-1000 EC (extrato de toranja mais flavonóides), e ECO-100 SC (bioflavonóides mais ácidos orgânicos, fitoalexinas cítricas, ácidos graxos glicerídeos e açúcares) inibiram em 80,1%, 79,0% e 76,5%, respectivamente, a podridão causada por Botrytis cinerea quando utilizados no tratamento pós-colheita de frutos de maçã sob condições controladas.Tratamento combinado de Biorend SC, com aplicação tanto em pré como no pós-colheita, proporcionou 49,9% de inibição da podridão, enquanto BC-1000 e ECO-100 EC não foram efetivos. Nenhum desses produtos inibiu a podridão cinzenta, quando utilizados em tratamento de pré-colheita em condições controladas ou em tratamento de pós-colheita em condições comerciais. O polissacarídeo algal ulvana, utilizado nos tratamentos de pós-colheita, reduziu em 56% a podridão cinzenta das maçãs em condições controladas, mas não teve efeito inibitório nos tratamentos combinados de pré e pós-colheita. A incapacidade dos produtos em ativar mecanismos de defesa (quitinases e peroxidases) nos frutos, após o tratamento em pré-colheita, foi consistente com a falta de controle da podridão nesse tipo de ensaio. Pelos resultados, sugere-se que os produtos naturais utilizados apresentam potencial para a utilização no manejo integrado da podridão de Botrytis quando aplicados em pós-colheita.http://ref.scielo.org/kcxb9

Persistent, symptomless, systemic, and seed-borne infection of lettuce by Botrytis cinerea

Experiments are presented which show that Botrytis cinerea, the cause of gray mould disease, is often present in symptomless lettuce plants as a systemic, endophytic, infection which may arise from seed. The fungus was isolated on selective media from surface sterilized sections of roots, stem pieces and leaf discs from symptomless plants grown in a conventional glasshouse and in a spore-free air-flow provided by an isolation propagator. The presence of B. cinerea was confirmed by immuno-labelling the tissues with the Botrytis-specific monoclonal antibody BC-12.CA4. As plants grew, infection spread from the roots to stems and leaves. Surface sterilization of seeds reduced the number of infected symptomless plants. Artificial infection of seedlings with dry conidia increased the rate of infection in some experiments. Selected isolates were genetically finger-printed using microsatellite loci. This confirmed systemic spread of the inoculating isolates but showed that other isolates were also present and that single plants hosted multiple isolates. This shows that B. cinerea commonly grows in lettuce plants as an endophyte, as has already been shown for Primula. If true for other hosts, the endophytic phase may be as important a component of the species population as the aggressive necrotrophic phase

Ethanol Vapours to Complement or Replace Sulfur Dioxide Fumigation of Table Grapes

Recent studies have shown that dipping table grapes in ethanol solutions at harvest improved storage of the fruit. We report here the first results obtained by treating "Chasselas" table grapes (Vitis vinifera) with ethanol vapours over the storage period. We tested the effect of ethanol at 0, 4 and 8 g/kg fruit during cold storage for 2, 4 and 6 weeks. We measured berry shatter, stem browning, Botrytis rot incidence and sensory appreciation by tasting panels. Ethanol vapours reduced Botrytis rot incidence and berry shatter, but hastened stem browning. Sensory analyses did not detect any differences between treatments