Occurrence Of Fungal Diseases Research Articles

The Effect of Pre-Harvest Treatment with Fungicide on the Storage Potential of Root Vegetables

The Effect of Pre-Harvest Treatment with Fungicide on the Storage Potential of Root Vegetables The results of experiments conducted over many years indicate that proper agrotechnical methods of cultivating root vegetables (carrot, parsley, and celeriac) such as while proper crop rotation, fertilization, and optimal storage conditions effects the quality and storage potential of these vegetables, while preharvest protection did not have a significant effect on storage life and the occurrence of fungal diseases during long-term storage. The highest effectiveness in pre-harvest protection of the studied vegetable species against alternaria leaf blight on carrot, powdery mildew on parsley, and septoria leaf spot on celeriac was exhibited by: azoxystrobin, azoxystrobin + chlorotalonil, and pyraclostrobin + boscalid, which proved to be highly effective in preventing infection with storage diseases (over 90%), and had a beneficial effect on the storage life of these vegetable roots in comparison with unprotected objects. Significantly lower effectiveness in pre-harvest protection and smaller effect on storage life was shown by natural fungicidal products (chitosan, orange oil, melaleuca oil). Although they showed lower effectiveness, they can be recommended for use in the integrated and ecological systems of producing root vegetables for long-term storage.

Fungal‐type Dysbiosis of the Gut: The Occurrence of Fungal Diseases and the Response to Challenge with Yeasty and Mould‐containing Foods

Patients with fungal‐type dysbiosis of the gut whose symptoms had cleared were asked to fill in questionnaires concerning current and previous fungal diseases and the effects of reintroducing certain foods into the diet. In 84% of cases symptoms had cleared on diet alone, the remaining 16% required antifungal therapy in addition to dietary intervention. When yeast extract, leavened bread, alcoholic drinks and mould‐containing cheeses were serially re‐introduced into the diet, over half the patients reported recurrence of symptoms with each of the foods, but the pattern varied with different patients, few reacting to all they tested. Many had, or had had, fungal diseases but no adequate published surveys of the prevalence of current or past fungal diseases were identified for comparison after a careful literature search. The implications of these findings are discussed.

Soybean yield estimation by an agrometeorological model in a GIS

Agrometeorological models interfaced with the Geographic Information System - GIS are an alternative to simulate and quantify the effect of weather spatial and temporal variability on crop yield. The objective of this work was to adapt and interface an agrometeorological model with a GIS to estimate soybean [Glycine max (L.) Merr.] yield. Yield estimates were generated for 144 municipalities in the State of Paraná, Brazil, responsible for 90% of the soybean production in the State, from 1996/1997 to 2000/2001. The model uses agronomical parameters and meteorological data to calculate maximum yield which will be penalized under drought stress. Comparative analyses between the yield estimated by the model and that reported by the Paraná State Department of Agriculture (SEAB) were performed using the "t" test for paired observations. For the 1996/1997 year the model overestimated yield by 10.8%, which may be attributed to the occurrence of fungal diseases not considered by the model. For 1997/1998, 1998/1999 and 1999/2000 no differences (P > 0.05) were found between the yield estimated by the model and SEAB's data. For 2000/2001 the model underestimated yield by 10.5% and the cause for this difference needs further investigation. The model interfaced with a GIS is an useful tool to monitor soybean crop during growing season to estimate crop yield.

Fungal-type Dysbiosis of the Gut: The Occurrence of Fungal Diseases and the Response to Challenge with Yeasty and Mould-containing Foods

Fungal-type Dysbiosis of the Gut: The Occurrence of Fungal Diseases and the Response to Challenge with Yeasty and Mould-containing Foods

Meteorological method based on wet foliage to determine areas at high risk of fungal epidemics

The occurrence of fungal diseases is closely linked to specific atmospheric conditions affecting the life cycle of the fungus. Popular beliefs as well as scientific knowledge are in agreement on the effect of high temperature and moisture on fungal epidemics. The presence of a film of water on a plant, during an uninterrupted number of threshold hours is in many cases a necessary, and sometimes sufficient condition for fungal infection to develop. In this paper, we present a method to estimate the sequence of hours of wet and dry vegetal surface. Conventional hourly meteorological data are used. The accuracy of this method has been studied over an ideal sunflower field located in Balcarce (Buenos Aires, Argentina) with promising results.

Water vapour transfer in a plastic house equipped with a dehumidification heat pump

Improvement of greenhouse insulation, for example through using a double inflated wall or thermal screens, leads to changes in the microclimate of the protected cultivation. The low air exchange rate induces an increase in the inside air humidity and the development of condensation on the walls and roof which causes water to drip on to the crops. Consequently, the occurrence of fungal diseases and physiological disorders increases and greenhouse air dehumidification is necessary to combat these. In this paper, the greenhouse air dehumidification possibilities are analysed with both experimental and theoretical evaluations of the water vapour transfer between the different sub-systems (soil, crop, inside air, roof, outside air, heat pump), considered as sources or sinks of water vapour. The water vapour fluxes were estimated from measurements of temperature, heat flow, humidity and radiation. A dynamic model of water vapour exchange was developed and compared with the experimental results. It showed that the heat pump did not reduce significantly the inside air humidity, but eliminated almost completely the water condensation on the roof (and dripping of water on to the crops). This model allows the determination of the size of the dehumidification system required, according to the characteristic parameters of the greenhouse and of the crop, namely, air temperature and humidity set points, air changes, crop leaf area index, stomatal and aerodynamic resistance.

Water vapour transfer in a plastic house equipped with a dehumidification heat pump

Improvement of greenhouse insulation, for example through using a double inflated wall or thermal screens, leads to changes in the microclimate of the protected cultivation. The low air exchange rate induces an increase in the inside air humidity and the development of condensation on the walls and roof which causes water to drip on to the crops. Consequently, the occurrence of fungal diseases and physiological disorders increases and greenhouse air dehumidification is necessary to combat these. In this paper, the greenhouse air dehumidification possibilities are analysed with both experimental and theoretical evaluations of the water vapour transfer between the different sub-systems (soil, crop, inside air, roof, outside air, heat pump), considered as sources or sinks of water vapour. The water vapour fluxes were estimated from measurements of temperature, heat flow, humidity and radiation. A dynamic model of water vapour exchange was developed and compared with the experimental results. It showed that the heat pump did not reduce significantly the inside air humidity, but eliminated almost completely the water condensation on the roof (and dripping of water on to the crops). This model allows the determination of the size of the dehumidification system required, according to the characteristic parameters of the greenhouse and of the crop, namely, air temperature and humidity set points, air changes, crop leaf area index, stomatal and aerodynamic resistance.