Inhibitory Effect of (-)-myrtenol alone and in combination with antifungal agents on Candida spp.

The aim of this study was to examine the effects of (-)-myrtenol alone and combined with antifungal agents against Candida spp. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration of (-)-myrtenol and fluconazole against C. albicans and C. parapsilosis strains was obtained using CLSI guidelines. Combination of (-)-myrtenol with antifungal drugs was determined by checkboard test. The (-) myrtenol showed MIC ranging from 256 to 512 µg/mL against both species assay. And the MFC was 512 µg/mL, demonstrated nature fungicidal (MFC/MIC < 4). In addition, combination of antifungal agents (amphotericin B and fluconazole) and (-) myrtenol showed synergistic and additive effects on strains assays. Based on these results, the present study demonstrates that (-) myrtenol showed strong fungicide activity against Candida spp. In addition, Combination of antifungal agents and (-) myrtenol reduces the effective concentrations of both the agents with synergistic to additive effects. Therefore, (-) myrtenol has potential to be developed into an antifungal agent.

Endophytic Microorganisms as an Alternative for the Biocontrol of Phytophthora spp.

The genus Phytophthora with more than 100 described species and 58 officially recognized, phylogenetically distributed in ten clades, are important pathogenic oomycete chromists that cause important diseases in agricultural crops, trees and forests worldwide. This genus is known as \"The Plant Destroyer” which causes great economic losses with costs between 2 and 7 billion dollars per year in agricultural systems and unquantifiable losses in natural ecosystems. The host plants of the genus Phytophthora can vary from a wide range in some species to only one host, however, the host plants of the new species are still being determined and therefore the range continues to expand, that makes control exceedingly difficult. Plant damage can range from alterations in roots, fruits, trunks, stems, foliage and crown to invasive processes in highly susceptible species. Considering the wide range of hosts and organs that can be affected by Phytophthora, the use of endophytic microorganisms for the biocontrol of this phytopathogen can be an alternative to avoid losses of both crops and forests worldwide. Endophytes are microorganisms that live inside plant tissues without causing disease under any circumstances. The fact that endophytic microorganisms are able to colonize an ecological niche similar to that of some plant pathogens qualifies them as potential biocontrol agents. This chapter describes the endophytic bacteria and fungi isolated from different plant species that have shown antagonistic activity against different species of Phytophthora, as well as the metabolites isolated from these microorganisms that have shown fungicide activity and other biocontrol strategies (enzyme production, siderophores, substrate competition, among others) against Phytophthora.

Graphene oxide as pesticide carriers for enhancing fungicide activity against Magnaporthe oryzae

The fungus Magnaporthe oryzae causes disastrous consequences for rice growth. Carbendazim (CBZ) has been widely used for the disease management. However, because of the heavy use of traditional CBZ, a...

Effect of Candida intermedia LAMAP1790 Antimicrobial Peptides against Wine-Spoilage Yeasts Brettanomyces bruxellensis and Pichia guilliermondii

Wine spoilage yeasts are one of the main issues in the winemaking industry, and the control of the Brettanomyces and Pichia genus is an important goal to reduce economic loses from undesired aromatic profiles. Previous studies have demonstrated that Candida intermedia LAMAP1790 produces antimicrobial peptides of molecular mass under 10 kDa with fungicide activity against Brettanomyces bruxellensis, without affecting the yeast Saccharomyces cerevisiae. So far, it has not been determined whether these peptides show biocontroller effect in this yeast or other spoilage yeasts, such as Pichia guilliermondii. In this work, we determined that the exposure of B. bruxellensis to the low-mass peptides contained in the culture supernatant of C. intermedia LAMAP1790 produces a continuous rise of reactive oxygen species (ROS) in this yeast, without presenting a significant effect on membrane damage. These observations can give an approach to the antifungal mechanism. In addition, we described a fungicide activity of these peptides fraction against two strains of P. guilliermondii in a laboratory medium. However, carrying out assays on synthetic must, peptides must show an effect on the growth of B. bruxellensis. Moreover, these results can be considered as a start to develop new strategies for the biocontrol of spoilage yeast.

Curative Fungicide Activity Against Calonectria pseudonaviculata, the Boxwood Blight Pathogen1

Azoxystrobin, azoxystrobin plus benzovindiflupyr, kresoxim-methyl, propiconazole, pyraclostrobin, pyraclostrobin plus fluxapyroxad, tebuconazole, tetraconazole, thiophanate-methyl, and triflumizole fungicides were evaluated for curative and anti-sporulant activity against boxwood blight caused by Calonectria pseudonaviculata on detached leaves and whole boxwood plants (Buxus spp.). Pretreating detached leaves with 30 or 300 ppm a.i. 24 h prior to inoculation reduced disease compared to the untreated control for all fungicides. Fungicides were also applied 24 to 96 h post-inoculation. Only propiconazole reduced diseased leaf incidence to at least half of the control. When leaves were treated post-infection with 300 ppm propiconazole, tetraconazole, tebuconazole, or triflumizole, the pathogen did not sporulate over 2 wks. Propiconazole also reduced the percent of leaf area diseased; lesions were nearly 80% smaller with 300 ppm applied 48 h after inoculation. ‘True Dwarf' boxwood plants treated with 450 ppm thiophanate-methyl, 120 ppm pyraclostrobin or 150 ppm propiconazole 48 h after inoculation demonstrated that only propiconazole reduced the number of diseased leaves, blight lesions and the frequency of pathogen re-isolation. Experiments with ‘Green Mound' and ‘Green Mountain' boxwood cultivars and additional fungicides applied 48 h after inoculation demonstrated that propiconazole at 300 ppm, pyraclostrobin plus fluxapyroxad (150 ppm each) and azoxystrobin (135 ppm) plus benzovindiflupyr (67.5 ppm) reduced disease. Index words: fungicide management, Buxus, chemical disease management Chemicals used in this study: azoxystrobin (Heritage 50 WG), azoxystrobin plus benzovindiflupyr (Mural 30, 50 WG), kresoxim-methyl (Cygnus 50 WG), propiconazole (ProCon-Z 14.3 L), pyraclostrobin (Insignia 20 WG), pyraclostrobin plus fluxapyroxad (Orkestra Intrinsic 21.26 SC), tebuconazole (Torque 38.7 SC), tetraconazole (Minerva 11.6 SC), thiophanate-methyl (3336 50% WP), triflumizole (Procure 480 SC). Species used in this study: boxwood (Buxus L.), boxwood blight (Calonectria pseudonaviculata (Crous, J.Z. Groenew. & C.F. Hill) L. Lombard, M. J. Wingf. & Crous.

Cyclic Synthetic Peroxides Inhibit Growth of Entomopathogenic Fungus Ascosphaera apis without Toxic Effect on Bumblebees

In recent years, the number of pollinators in the world has significantly decreased. A possible reason for this is the toxic effects of agrochemicals reducing the immunity of insects that leads to their increased susceptibility to pathogens. Ascosphaera apis is a dangerous entomopathogenic fungus, afflicting both honeybees and bumblebees. We investigated fungicide activity of cyclic synthetic peroxides against A. apis isolated from Bombus terrestris L. The peroxides exhibited high mycelium growth inhibition of A. apis up to 94–100% at concentration 30 mg/L. EC50 values were determined for the most active peroxides. Two peroxides showed higher antifungal activity against A. apis than the commercial fungicide Triadimefon. The studied peroxides did not reduce the ability of bumblebees to fly and did not lead to the death of bumblebees. A new field of application for peroxides was disclosed.

Ozonized Gel Against Four Candida Species: A Pilot Study and Clinical Perspectives

Ozone therapy can display a wide range of clinical beneficial effects, including antimicrobial, immune-stimulant, analgesic, anti-hypoxic actions. However, there is still a paucity of data regarding the ozone fungicide activity. Oral Candida is the most common fungal infection in the mouth among denture wearers and people with weakened immune systems. In the case of generalized candidiasis or immunocompromised patients, systemic therapy is needed, while localized infections are treated with topic medications. However, many Candida strains are resistant to antifungal drugs. The aim of this preliminary analysis is to evaluate the antimycotic efficacy of a new ozonided oil (GeliO3), as a possible terapeutic alternative in local treatments of these infections, compared to chlorhexidine digluconate (Plak gel®). Chlorhexidine is a chemical synthesis disinfectant with a broad-spectrum antiseptic action, active against bacteria and fungi. Antimycotic activity was tested against the following four Candida species: C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, through an agar diffusion method. No significant differences were found between the growth inhibition zone diameters of the ozonized gel and chlorhexidine. The results indicated that the ozonized gel may help to combat Candida infections. Moreover, useful applications could be used to counteract Candida colonization of endosseous implants.

Influence of oxathiapiprolin on preinfectional and early infection stages of Plasmopara halstedii, downy mildew of the sunflower

Oxathiapiprolin is a recently introduced fungicide with particular activity against hemibiotrophic and biotrophic oomycetes. For Plasmopara halstedii, the downy mildew of the sunflower, no detailed studies for the activity of the pure compound on the preinfectional and early infection stages in which the fungicide could most effectively interfere with the life cycle of the pathogen have been reported. The fungicide was shown to be active against all stages of the pathogen starting from the release of the zoospores to the development of the mycelia and the formation of the sporangia. Differences in the sensitivity of the different developmental stages are in accordance with the suggested mechanism of the fungicide activity which targets sterol-binding proteins. The experiments showed that, in preventive treatments against very sensitive stages of the pathogen (such as germination of spores), extremely low concentrations of less than 1 ng/mL can completely protect the plants. Coating the seeds with oxathiapiprolin successfully prevented the seedlings from soil-borne infections. This is of particular importance in sunflower cultivation, because wind-borne infections on plants are much rarer and less harmful than soil-borne infections, which usually become systemic and lead to complete yield loss. The curative effects of oxathiapiprolin were shown on the leaf disks as well as on the infected young plants. However, this seems to be less important in sunflower cultivation than, for instance, in viticulture, because spraying sunflowers in the field after the germination of the seeds is uncommon (except in the ornamental cultivation of cut sunflowers).

Influence of biostimulants on productivity and quality of grapes

The summary results of researches on joint influence of the biopreparation containing microbic inoculants (Bacillus pumilus bacteria, strain 3-B) and humic substances (potassium humate) on agrobiological and economic indicators of Cabernet Sauvignon grapes. For defining of biological efficiency of the biostimulant on grapes the foliar nutrition of plants of grade of Cabernet Sauvignon was carried out in phases of sap flow and initial blossom. The biological product had significant effect on forming of bunches, and berries, promoting to increase on their weight. Crop yield of options of experience increased, in comparison with check option by 14-19%. There are no differences in the quality of the crop (total sugars and acids) between the variants of the experiment. Foliar nutrition of plants the microbiological product Bacillus pumilus, + potassium humate (3,0 l/hectare) promoted increase in fungicide activity of product from mildew (active ingredient - Mankotseb + Mefenoksam). At top-dressing of plants biological product the growth-regulating activity in experience options with assignment of dose of 2,0 l/hectare and 3,0 l/hectare, in comparison with check option significantly increased. Difference on ripening of whip it is not proved as for of options of experience, in comparison with check option, and for options among themselves.

AKTIVITAS FUNGISIDA BAHAN PENGAWET KAYU BERBAHAN AKTIF MAJEMUK TERHADAP JAMUR BIRU Diplodia sp

Fungicide Activity of Complex-Active Ingredient of Preservative Wood Against Bluestain of Diplodia sp. Wood preservatives containing chlorotalonyl 450 g/L and carbendazim 100 g/L (Entiblu 450/100SC) was a pesticide compound serves to prevent fungal attacks Diplodia sp on the media of PDA (Potato Dextrose Agars) and to prevent germination of the spores. Inhibition of the rate and intensity of Diplodia sp fungus attacks on the media in petridish indicated a slowing rate of growth of the mycelium. The results showed that the pesticides containing chlorotalonyl 450 g/L and carbendazim 100 g/L with a concentration of 2 x 1.5 kg/ m³ could prevent the growth of the mycelium of Diplodia sp, inhibition rate reached 100%. For single ingredient chlorotalonyl 75 % (Chlorotalonil 75 WP) a concentration of ½ x 0.375 kg/m³ had been able to prevent the growth of the mycelium up to 100 %, while in carbendazim 50 % (Carbendazim 50 WP) to reached 100 % inhibition at a concentration of 1 x 0.75 kg/m³. Pesticides which was a mixture of active ingredients chlorotalonyl 450 g/L and carbendazim 100 g/L no antagonism activity.Keywords : fungicide, complex active ingredient, bluestain of Diplodia sp, chlorotalonyl, carbendazim ABSTRAK Bahan pengawet kayu yang mengandung klorotalonil 450 g/L dan karbendasim 100 g/L (Entiblu 450/100SC) merupakan pestisida majemuk berfungsi untuk mencegah serangan jamur Diplodia sp pada media agar PDA (Potato Dextrose Agar) dan mencegah perkecambahan spora. Penghambatan laju dan intensitas serangan jamur Diplodia sp pada media dalam cawan petri ditunjukkan pelambatan kecepatan pertumbuhan miselium. Hasil pengujian menunjukkan bahwa pada pestisida yang mengandung klorotalonil 450 g/L dan karbendasim 100 g/L dengan konsentrasi 2 x 1,5 kg/m³ dapat mencegah pertumbuhan miselium Diplodia sp , tingkat penghambatan mencapai 100 %. Untuk bahan tunggal klorotalonil 75 % (Chlorotalonil 75WP) pada konsentrasi ½ x 0,375 kg/m³ telah mampu mencegah pertumbuhan miselium sampai 100 %, sedangkan pada karbendasim 50 % (Carbendazim 50 WP) untuk mencapai penghambatan 100 % baru pada konsentrasi 1 x 0,75 kg/m³. Pestisida yang merupakan campuran bahan aktif klorotalonil 450 g/L dan karbendasim 100 g/L tidak ada aktivitas antagonisme.Kata kunci : fungisida, bahan aktif majemuk, jamur biru Diplodia sp, klorotalonil, karbendasim