The quaternization reactions of nicotinamide, with different electrophiles: methyl iodide and substituted 2-bromoacetophenones (4-Cl, 4-Br, 4-H, 4-CH3, 4-F, 4-OCH3, 4-Ph, 2-OCH3, 4-NO2) are reported. The preparations were carried out by conventional synthesis and under microwave irradiation in absolute ethanol and acetone. The synthesis performed by microwave dielectric heating significantly improved yield, up to 8 times, and shortened down the reaction time from ca. one day in conventional, to 10–20 min. The structures of the synthesized compounds were confirmed by IR, 1H- and 13C-NMR spectroscopy, mass spectrometry and elemental analysis. The compounds have been screened for antifungal activities against Fusarium oxysporum, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiorum at concentrations of 10 µg/mL and 100 µg/mL. Six compounds showed the strong inhibition of mycelium growth at a concentration of 10 µg/mL. All tested compounds revealed the great inhibitory activities against S. sclerotiorum at a concentration of 100 µg/mL.
Ten novel isonicotinamide derivatives were prepared by quaternization reactions of isonicotinamide with methyl iodide and nine differently substituted 2-bromoacetophenones under rapid microwave irradiation of 10 minutes. The microwave preparations were significantly faster and with yields higher up to 8 times, than the preparations by conventional method. The structures of synthesized molecules were determined by one-and two-dimensional NMR and IR spectroscopy, mass spectrometry and elemental analysis. Antifungal activity of all compounds was tested in two different concentrations (10 and 100 µg mL -1 ) against Fusarium oxysporum, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiorum in vitro. From the antifungal assay it can be seen that the most prepared compounds have moderate to weak activity against M. phaseolina and F. culmorum. A very high inhibitory rate was observed against S. sclerotiorum, 62-87.5 % in concentration of 10 µg mL -1 and 83.7-93.2 % in concentration of 100 µg mL -1 .
The aim of this study was to determine the influence of liquid chicken manure preparation on nematode biodiversity as an indicator of soil health and agrochemical soil properties. The field experiment was conducted during two years into two treatments and three samplings per year. One plot was treated with liquid chicken manure preparation (LCMP) while the other plot, without manure application, was control (C). In the first year of this study, the treatments were conducted in the wheat plantation, while in the following year the culture was rapeseed. Results indicate that genus biodiversity was significantly higher in treatments with LCMP (18% in wheat, 28% in rapeseed). Indices of disturbance (MI, MI [2-5], PPI/MI) show statistically significant differences during the two years indicating ecosystem stability, reduction of plant parasitic nematodes and the multitude of beneficial nematodes in treatment with LCMP compared to C. The analysed agrochemical properties showed the increasement of organic matter content (60%) and P and K content in treatment with LCMP compared to C. It can be concluded that the use of LCMP significantly increases the nematode diversity and the stability of the soil ecosystem as well as a nutrient content in the soil which results in a reduced economic investment, primarily in the use of mineral fertilizers.
The aim of this study was to investigate the nematocidal effect of the preparations based on fluopyram (pesticide) and liquid chicken manure (natural amendment) on the population density of the root-knot nematodes, Meloidogyne spp. in carrot crops. The field experiment was set up in four treatments: control (C), fluopyram (FLU), fluopyram and liquid chicken manure (FLU+LCM) and liquid chicken manure (LCM) by a random block design in four replicates. Population density of Meloidogyne spp. juveniles varied between the treatments, and the number of Meloidogyne spp. was significantly decreased in all treatments with fluopyram (FLU and FLU+LCM). All amended treatments (FLU, FLU+LCM, LCM) decreased galling of the roots and had a positive effect on carrot yield. The population of Meloidogyne spp. juveniles increased with the plant growth, regardless of the treatments applied. Fluopyram negatively affected the biodiversity indicating greater disturbance for the nematode community structure in the soil. It can be concluded that fluopyram and liquid chicken manure have nematicidal potential, while liquid chicken manure maintained or enhanced nematode biodiversity.
Eleven pyridine derivatives were prepared by quaternization reactions by different synthetic routes: conventional, microwave, and ultrasound. Since acetone and other solvents used in conventional quaternization reactions are harmful, attempts were made to replace the organic solvents with more environmentally friendly alternative -deep eutectic solvents. The reactions were carried out using pyridine-3aldoxime, pyridine-4-aldoxime, isonicotinamide and nicotinamide as nucleophiles and three different dihaloalkanes as electrophiles: diiodopropane, dibromopropane and diiodohexane. The results showed that the microwave method using acetone as solvent was significantly faster and gave higher yields than the conventional method. In contrast, synthesis in the eutectic solvents choline chloride : urea gave significantly lower yields. The structures of the synthesized compounds were confirmed by 1 H and 13 C NMR spectroscopy, mass spectrometry and elemental analysis. The antifungal activity of all compounds was tested at two different concentrations (10 and 100 µg mL -1 ) against Botrytis cinerea, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiorum in vitro. All tested compounds showed excellent inhibitory activity against the studied phytopathogenic fungal species at a concentration of 100 µg mL -1 .
Dosadašnji načini kontrole uzročnika bolesti koji, među ostalim, podrazumijevaju uporabu fungicida prema novim zakonodavnim okvirima i novim strategijama u biljnom zdravstvu nailaze na sve veće restrikcije. Pronalaženje nekemijskih sredstava za zaštitu usjeva od biološki preparat, Fusarium graminearum, pšenica, zrnobolesti je od velikog interesa za poljoprivrednu proizvodnju, stoga je u našem istraživanju ispitan učinak novog biološkog preparata (BP) za kontrolu gljive Fusarium graminearum na klijancima pšenice. Biološki preparat primijenjen je na tri različita načina: inokulacijom zrna pšenice, zalijevanjem, te inokulacijom zrna i zalijevanjem. Utvrđeno je kako se intenzitet bolesti primjenom BP smanjuje, a najbolji rezultati dobiveni su inokulacijom zrna prije sjetve dok je zalijevanje površine BP polučilo slabije rezultate. Također, ukoliko je zrno već tretirano biološkim preparatom dodatna aplikacija zalijevanjem nije bila opravdana ni s ekološkog ni s ekonomskog aspekta.
Wilted hemp (Cannabis sativa L.) plants were observed in August 2019 in commercial fields around Osijek, Croatia. Plants and roots with disease symptoms were collected. The single-spored isolates produced septate cottony white to light pink aerial mycelium and purple undersurface on potato dextrose agar (PDA). Smooth and hyaline hyphae were branched and septate. Macroconidia were fusiform to sickle-shaped with foot-shaped basal cell, elongated apical cell and three to five septa. Sequencing of the internal transcribed spacer and the partial elongation factor 1-α gene identified species as Fusarium oxysporum. Artificial infection fulfills Koch’s postulates, producing plants which showed stunted growth and wilt symptoms similar to those observed in the commercial fields. Control seedlings remained symptomless and healthy. To the best of our knowledge, this is the first report of hemp Fusarium wilt causing F. oxysporum in Croatia. Considering that F. oxysporum has been reported in main field crops in Croatia, the presence of this pathogen could cause economically significant hemp production decreases, especially in humid and cold springs and susceptible varieties.
Zbog stalnog povećanja upotrebe kemijskih pesticida i njihovog štetnog djelovanja na ljudsko zdravlje i okoliš, sve veće zanimanje pobuđuju metode biološke kontrole uzročnika biljnih bolesti. Biološka kontrola je mjera koja podrazumijeva korištenje mikroorganizama koji smanjuju populaciju štetnika i patogena i na taj način štite biljku i kontroliraju razvoj bolesti. U Hrvatskoj je trenutno na tržištu prisutan samo jedan biofungicid, na bazi bakterije iz roda Pseudomonas, za suzbijanje uzročnika bijele noge (Rhizoctonia solani) na krumpiru, batatu, čičoki i kineskom jamu te uzročnika srebrolikosti gomolja (Helminthosporium solani) na krumpiru. Vrste Bacillus thuringiensis, Bacillus subtilis i Pseudomonas fluorescens su najvažniji predstavnici bakterija uključenih u biokontrolu protiv uzročnika biljnih bolesti. Do danas je na svjetskom tržištu prisutno ili je u procesu registracije 28 sredstava na bazi različitih vrsta roda Trichoderma, koji većinom djeluju protiv fitopatogenih gljiva iz rodova Pythium, Rhizoctonia i Fusarium. Najzastupljenije vrste roda Trichoderma koje se koriste u biološkoj kontroli su Trichoderma harzianum, Trichoderma viride i Trichoderma koningii. Upotreba antagonističkih gljiva i bakterija u biološkoj kontroli brojnih uzročnika bolesti predstavlja važnu alternativu kojom bi se mogli zamijeniti kemijski pesticidi ili u što većoj mjeri smanjiti njihova primjena. Cilj rada je prikazati antagonističke gljive i bakterije koje se koriste u biološkoj kontroli te opisati njihove složene mehanizme djelovanja.
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