Effect of Fungicides on Bayberry Decline Disease by Modulating Rhizosphere Soil Properties, Microflora, and Metabolites (original) (raw)
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Effect of Fungicide Application on Lowbush Blueberries Soil Microbiome
Microorganisms
Lowbush blueberries (Vaccinium sp.) are perennial crops produced throughout eastern Canada and Maine through management of wild populations. Given the constraints of this cropping system, the application of fungicides is critical to reducing disease pressure and ensuring consistent yields. However, as plant health is intertwined with soil health, it is important to consider the impact of fungicides on microbial communities. To understand the effects of fungicides in this context, bacterial and fungal microbial communities from fungicide-treated plots, as well as untreated control plots (UTG) were analyzed using amplicon sequencing. The fungicides, considered collectively as a combined treatment group (CTG), lead to a loss in fungal richness. One family, Clavariaceae, had an increased abundance under prothioconazole relative to UTG. This finding may be significant as taxa in Clavariaceae have been thought to potentially form ericoid mycorrhizae with Vaccinium. Five functional pathway...
2018
The object of research was the soil from an orchard after 27 years of apple cultivation, showing signs of fatigue resulting in weaker growth of apple seedlings planted into it, and the soil sampled on the same farm, but not used for growing fruit trees. The physicochemical properties of both soils did not differ significantly. In sick soil, no pathogens of fungal or fungi-like origin were found, and the number of nematodes was below the threshold of economic threat. There is a suspicion that abiotic factors could be responsible for soil fatigue. It has been demonstrated that the cultivation of spring and winter wheat, triticale and white mustard before planting apple 'Antonovka' seedlings, had a positive impact on their growth. The best effect was obtained after the cultivation of white mustard or after the introduction of mustard seed meal into the soil, which was also confirmed by measurements of the intensity of apple seedlings photosynthesis. The cultivation of these phytosanitary plants or the addition of mustard seed meal positively influenced the biological potential of the soil expressed by a significant increase in the population of bacteria from the genera Pseudomonas and Bacillus. There was also a very large increase in the number of Trichoderma spp. fungi after the addition of mustard seed meal into the soil and winter wheat cultivation.
Effects of Prochloraz fungicide on soil enzymatic activities and bacterial communities
Ecotoxicology and Environmental Safety, 2011
We studied in the laboratory the effect of Prochloraz fungicide on the biological properties (soil enzymatic activities and soil bacterial communities) of a Plaggic Anthrosol. Five hundred grams of soil (o 2 mm) was mixed with three dosages of Prochloraz (1, 2, and 4 l ha À 1) for 83 days. A non-Prochloraz polluted soil was used as control. Following commercial recommendations, fungicide was applied four times during the incubation experiment. For all treatments, the soil ergosterol and levels of dehydrogenase, urease, b-glucosidase, and phosphatase activity were measured at nine different times (0, 1, 21, 22, 41, 42, 62, 63, and 83 days). The 16S rDNA-DGGE profiles in all treatments were determined at the beginning and end of the incubation period. At the end of the experiment, a significant decrease in ergosterol by 72.3%, 80.8%, and 83.1%, compared with control soil, was observed when 1, 2, and 4 l ha À 1 , respectively, was added. Soil enzymatic activities increased when the Prochloraz applied to the soil increased, possibly because the fungicide is used by bacterial communities as a source of energy and nutrients. The 16S rDNA-DGGE profiles indicated that the fungicide did not negatively affect soil bacterial biodiversity. These results suggested that the fungicide Prochloraz has a very interesting agronomic effect, possibly due to the negative effect on soil fungal population stimulating the growth of soil bacterial activity.
Effect of microbiological products on soil properties in the conditions of replant disease
Zemdirbyste-Agriculture, 2013
The phenomenon of soil fatigue, causing replant disease, can occur in the conditions of monocultural cultivation. This evokes a decrease in the soil productive value because of the deterioration of biological soil properties. In the present work, an attempt has been made to improve the biological activity of a replanted soil by the use of three micro-biological preparations: EM-5, Bacto Fill 10B and Humobak PG. The biological activity of soil was estimated using two parameters: the activity of soil enzymes, dehydrogenase and protease as well as the respiratory activity. The application of microbiological preparations significantly increased the activity of dehydrogenase in the soil. The effect of two among the three applied preparations exerted a smaller influence on the protease activity. An exception was the Humobak PG preparation whose application distinctly increased the activity of protease in the replanted soil. On the other hand, the vegetation period was found to exert a significant effect both on soil enzymatic and respiratory activity. In the autumn period, the activity of both enzymes in the soil was higher, in comparison with the spring period, while the respiratory activity was higher in the spring. The functioning of soil microorganisms depends on some physico-chemical properties of soil. In our work, the studied preparations did not have any significant effect on the changes in the pH values. However, the effect was more perceivable on the content of organic carbon in the soil. The application of microbiological preparations in replanted soil caused a change in the plant growth and fruiting. Among others, an increase in the average leaf area of strawberry, the average fruit mass and the content of juice extract in fruits was observed.
Occurrence of fungicide residues on Argentinean blueberry fruit and juice samples.
Sift Desk Journals, 2016
Azoxystrobin, boscalid, cyprodinil, fludioxonil and pyraclostrobin are fungicides commonly used in Argentina against different fungus contaminations in the blueberry field. The presence of these fungicides was investigated in 50 samples of blueberry fruit and 15 samples of blueberry juice purchased in Argentina. Fungicide residues were determined by solid-phase microextraction (SPME) coupled to gas chromatography with micro-electron capture and nitrogen phosphorous detector. The average concentrations of azoxystrobin were 48 ?g/kg in blueberry fruit. Average of boscalid were 43 and 239 ?g/kg, of cyprodinil 1581 and 852 ?g/kg, of fludioxonil 1077 and 2842 ?g/kg, and of pyraclostrobin 578 and 3414 ?g/kg, in fruits and juice respectively. The higher concentrations of fungicides were found in those cases where the time between the application of the compound and the fruit’s commercialization was shorter than the fungicide’s half-life.
2021
Entomopathogenic fungi (EPF) contribute to different ecosystem services. However, factors affecting their natural occurrences in soil remain poorly understood. In a previous study, 81 soil samples were subjected to insect baiting using Galleria mellonella and Tenebrio molitor to isolate EPF from Portuguese vine farms. Here, soils yielding any of the four common EPF, i.e., Beauveria bassiana, Purpureocillium lilacinum, Metarhizium robertsii, and Clonostachys rosea f. rosea, were correlated with their chemical properties. Beauveria bassiana was negatively affected by higher available P (p = 0.02), exchangeable K-ions (p = 0.016) and positively affected by higher soil pH_H2O (p = 0.021). High exchangeable K-ions inhibited P. lilacinum (p = 0.011) and promoted C. rosea f. rosea (p = 0.03). Moreover, high available K also suppressed P. lilacinum (p = 0.027). Metarhizium robertsii was inhibited by higher organic matter content (p = 0.009), higher C:N (p = 0.017), total N (p = 0.007), and ...
Microorganisms, 2020
Bayberry (Myrica rubra) is a commercial fruit in China. For the past seven years, twig blight disease has been attacking bayberry plantations in Shantou City, Guangdong Province, China, leading to destructive damage and financial loss. In this study, five fungal species associated with twig dieback and stem blight were identified based on morphological characteristics combined with multilocus sequence analysis (MLSA) on the internal transcribed spacer (ITS) region, partial sequences of β-tubulin (tub2), translation elongation factor 1-α (tef1-α), large subunit ribosomal RNA (LSU) and small subunit ribosomal RNA (SSU) genes, which are Epicoccum sorghinum, Neofusicoccum parvum, Lasiodiplodia theobromae, Nigrospora oryzae and a Pestalotiopsis new species P. myricae. P. myricae is the chief pathogen in fields, based on its high isolation rate and fast disease progression after inoculation. To our knowledge, this is the first study reporting the above five fungi as the pathogens responsi...
Background Without effective chemical treatments, there is an increased interest on biological control of plant diseases. Trichoderma and Bacillus species have shown biocontrol potential against several grapevine diseases. However, few studies have investigated the impact of introducing beneficial microorganisms in rhizosphere, on the indigenous soil existent microbiome. Plant-associated microbiomes are complex, and there is a limited knowledge of the mechanisms that maintain and stimulate specific plant-associated microbial communities. In this study, we tested the hypothesis that the introduction of the biological control agents (BCAs) Bacillus subtilis PTA-271 (Bs PTA-271) and Trichoderma atroviride SC1 (Ta SC1) produce distinctive modifications in the composition and co-occurrence network structure of the grapevine rhizosphere microbial community, as well as grapevine induced defenses. Results Our results demonstrated that, the fungal microbiome is more affected by factors such ...
Canadian Journal of Plant Pathology, 2021
Botrytis blight is an economically important disease of lowbush blueberry that causes significant yield loss annually. In this study, four biofungicides, Diplomat 5SC (polyoxin D), Timorex Gold (tea tree oil), Fracture (BLAD) and Serenade MAX (Bacillus subtilis) were evaluated for their disease suppression potential against B. cinerea individually and in rotation with Switch ® under field conditions. Three applications of each biofungicide were made for the stand alone treatment at 7-10 days' interval with Switch ® replacing the 2 nd application in the combined treatment. Results indicated that the products have potential for use as a biofungicide in lowbush blueberries. All the stand alone and rotational applications brought about significant reduction in disease development, especially in 2019. The application of Diplomat 5SC and Fracture ®-Switch ® rotation decreased disease development by over 63% in 2018. In 2019, all stand alone treatments reduced disease development by more than 42% whereas their rotation with switch reduced disease by over 69% at Earltown and at least 30% at Farmington. Stand alone Diplomat 5SC ® and Timorex Gold ® along with Fracture ® , Timorex Gold ® and Serenade MAX rotation resulted in over 20% more berries. This study suggests that the biofungicides and their integration with chemical fungicides have the potential as an alternative management strategy against Botrytis blossom blight to reduce the use of conventional fungicides and produce fruit with no detectable fungicide residues.