Ogorčice so organizmi, ki jih zaradi njihove številčnosti, raznolikosti in prilagodljivosti najdemo praktično povsod. Medtem ko je večina ogorčic koristnih, pa poznamo tudi take, ki s svojim ...parazitiranjem povzročajo škodo. Med škodljive ogorčice uvrščamo tudi rastlinsko-parazitsko vrsto Xiphinema index. Najdemo jo lahko v bližini korenin žlahtne vinske trte (Vitis vinifera L.), saj je prav ta njena glavna gostiteljica. Ogorčica ni tako problematična z vidika neposrednega napada korenin, ampak vinski trti predstavlja grožnjo zaradi prenosa in vnosa virusa pahljačavosti listov vinske trte (GFLV) iz rodu Nepovirus. Virus namreč na vinski trti povzroči bolezen kužne izrojenosti vinske trte, kar vodi v ekonomsko nekonkurenčnost vinogradov. Okužba lahko privede tudi do več kot 80 % izpada pridelka. V izogib nenadzorovanemu širjenju ogorčic in posledično okužbam v vinogradih je pomembna preventiva, saj poleg prenosa s sadilnim materialom, pomembnega prenašalca predstavljata tudi kmetijska mehanizacija in fizični prenos z orodjem. Ker se je kemično zatiranje ogorčice X. index zaradi njene trdoživosti in razporeditve v tleh izkazalo za neučinkovito, je potrebno v prihodnje stremeti k alternativnim in predvsem učinkovitejšim pristopom. Poleg vmesnih posevkov so preverjali delovanje pripravkov na podlagi nekaterih bakterij in gliv, ki predstavljajo velik potencial za nadaljnja raziskovanja.
The use of entomopathogenic fungi represents one of the most important non-chemical alternatives for pest control in crop production. In addition to their pathogenicity to arthropods, they have many ...other important effects that favor their use in biological control. They live in plants as endophytes and have an inhibitory effect on plant pathogens. They inhabit the rhizosphere of many plants in natural and agricultural ecosystems and have a stimulatory effect on their growth and development. These recently acquired ecological functions are not yet fully understood, but point to the broader potential of using entomopathogenic endophytic fungi in crop production, not only as biopesticides but also as mycofungicides and growth stimulants (biostimulants). To achieve the full potential of entomopathogenic endophytic fungi in daily agricultural practice, practical application should be considered in the development of commercial products and the application techniques of entomopathogenic endophytic fungi that allow successful colonization of plants should be considered.
In recent years, the less-studied
mycotoxins have attracted increasing interest due to the lack of survey data and their ability to cause toxic effects in animals and humans. To fill the gap, the aim ...of this three-year survey was to investigate the presence and co-occurrence of
and other mycotoxins in a total of 433 cereal grain samples from Slovenian farms and agricultural cooperatives from 2014 to 2016. Using the multi-mycotoxin method, 14 mycotoxins were determined. In 53% of 433 analysed samples, contamination with at least one mycotoxin was found. Deoxynivalenol (DON) and tenuazonic acid (TeA) were present in 32% and 26% of cereal grain samples, respectively, whereas alternariol (AOH), tentoxin (TEN), alternariol monomethyl ether (AME), 3- and 15-acetyldeoxynivalenol (3- and 15-AcDON), and zearalenone (ZEN) were present in fewer than 15% of the samples. Ochratoxin A (OTA) was found in one rye sample, while diacetoxyscirpenol (DAS), HT-2 and T-2 toxin, and fumonisins B
and B
(FB1 and FB2) were not detected. The highest maximum and median concentrations of
toxins were determined in spelt in 2016 (TeA, 2277 µg/kg and 203 µg/kg, respectively), and those of
toxins in wheat in 2015 (DON, 4082 µg/kg and 387 µg/kg, respectively). The co-occurrence of two or more mycotoxins was found in 43% of the positive samples. The correlations between
toxins were very weak but statistically significant (r: 0.15-0.17,
: 0.0042-0.0165). A well-known correlation between
toxins DON and ZEN was weak and highly significant (r = 0.28,
< 0.0001).
This four-year study reports the occurrence of ergot alkaloids (EAs) in cereals intended for animal feeding collected in Slovenia. A total of 517 samples of cereals were analysed using liquid ...chromatography-tandem mass spectrometry for the presence of EAs. The sample set included wheat, rye, triticale, oat, spelt and barley. The study revealed that 17% of the analysed cereal samples were contaminated with at least one ergot alkaloid. EAs have two epimeric forms: -ine and -inine. The incidence rates of the -ine and -inine forms in the analysed samples were 16% and 15%, respectively. The highest contamination rates were observed in rye (54%), oat (50%) and spelt (30%), where the highest mean concentrations of total EAs were also determined (502 µg/kg, 594 µg/kg and 715 µg/kg, respectively). However, the highest concentrations of total EAs were found in wheat and rye (4217 µg/kg and 4114 µg/kg, respectively). The predominant EAs were ergometrine, ergosine and ergocristinine. The occurrence of six or more ergot alkaloids was observed in 49% of the positive samples. A weak correlation (
= 0.284) in the positive samples was found between the mass of sclerotia and the total concentrations of EAs using the Spearman correlation coefficient.
The two spotted spider mite, Tetranychus urticae C. L. Koch, 1836 is one of the most important pests of greenhouse crops worldwide. Due to its polyphagic range of hosts and rapid development it forms ...great populations and as such represents a suitable host/prey for lots of natural enemies usable in biological control. Most commonly used predators of Tetranychid mites are predatory mites (Phytoseiulus persimilis Athias-Henriot, 1957, Amblyseius swirskii Athias-Henriot, 1962 ,…), but among most voracious predators is the larva of a predatory gall midge, Feltiella acarisuga (Vallot, 1827) that was found also in greenhouses of the Biotechnical Faculty in Ljubljana on eggplant leaves in 2017. Besides the predatory gall midge also another predator, staphylinid Oligota oviformis Casey, 1893 beetles and larvae were found in great numbers. After positive identification of F. acarisuga found naturally in Slovenia, it can be added to the list of indigenous species of natural enemies and thus can be used in biological control programs in greenhouse crop protection against spider mites.
Ash dieback is caused by a highly pathogenic fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea). Possibilities for disease control are limited, and treatment of fallen leaf debris to ...prevent sporulation of the pathogen is one of the possible options to control the disease. In some cases chemical treatments could be used, but data on effective chemical agents for control of the ash dieback are lacking. The purpose of this study was to examine the effect of different chemical fungicides and urea on the pathogen. Out of eight tested fungicides, mycelial growth in Petri plates as well as development of H. pseudoalbidus apothecia on ash leaf petioles were most efficiently inhibited by carbendazim. Urea also proved to be effective in prevention of apothecial formation. In addition to inhibition of the pathogen, urea accelerates the degradation of treated leaf debris. Therefore, the use of urea for treatment of infected ash leaf debris could be more effective than the use of fungicides and also more environmentally acceptable.
The primary aim of this study was to establish a micropropagation procedure
for the Slovenian frost-tolerant olive cultivar ?Istrska belica?.
Establishing an in vitro culture was very difficult due ...to constant
contaminations, tissue browning and stunted shoot growth. A sterile shoot
culture was finally achieved by washing with running tap water, immersing in
a mixture of ascorbic and citric acid and sterilizing with 70% ethanol and
dichloroisocyanuric acid. Shoot growth was optimal on DKW medium supplemented
with 4 mg/L of 2iP. Even in optimized conditions, sporadic fungal outbursts
occurred. Fungi were isolated and their taxonomic origin was determined by
morphological observation and molecular identification. Based on BLAST
queries in the NCBI database, five genera of fungi were identified:
Cladosporium, Chaetomium, Preussia, Biscogniauxia and Sistotrema, the last
three genera being isolated from olives for the first time. A detailed
literature search was performed to provide data on previous reports of these
genera in relation to their putative endophytic presence and their possible
pathogenic status. This is the first study reporting the presence of
endophytic fungi in olive tissue culture. The information provided in this
work can be very useful for the optimization of micropropagation protocols of
recalcitrant olive cultivars and can potentially improve field performance of
nursery plants.
nema
Several phytopathogenic Fusarium species occurring worldwide on cereals as causal agents of ‘head blight’ (scab) of small grain cereals and ‘ear rot’ of maize, are capable of accumulating, in ...infected kernels, several mycotoxins some of which of notable impact to human and animal health. Fusarium graminearum, F. culmorum, F. poae, F. avenaceum and Microdochium nivale predominantly cause Fusarium diseases of small-grain cereals. Maize is predominantly attacked by F. graminearum, F. moniliforme, F. proliferatum and F. subglutinans. The review is focused on the influence of climatic variables, particularly temperature, humidity and rainfall on growth, reproduction, survival, competitive ability, mycotoxicity and pathogenicity of Fusarium fungi commonly isolated from wheat, barley and maize.
The in vitro effect of five commonly used herbicides viz., pyridate, fluazifop-P-butyl, foramsulfuron, tembotrione and S-metolachlor on mycelial growth of entomopathogenic fungus Beauveria ...bassiana (ATCC 74040) was evaluated each at different concentrations: 100, 75, 50, 25, 12.5, 6.25 and 0% of recommended field application rate on PDA agar plates at 15 and 25°C. The herbicides tested were classified in 1-4 scoring categories based on reduction in mycelial growth: 1 = harmless (<25% reduction), 2 = slightly harmful (25-50%), 3 = moderately harmful (51-75%), harmful (>75%) in toxicity tests. All the five herbicides had fungistatic effect to B. bassiana at varying intensities depending on their concentrations in medium. The present study showed that B. bassiana is very sensitive to the herbicides tested, particularly at recommended as well as lower field dosage. The selected herbicides foramsulfuron, tembotrione and S-metolachlor have strong fungistatic effect on mycelial growth (> 75% inhibition) at 15 °C and concentrations from 50 to 100%. Foramsulfuron has fungicidal effect at 100 % concentration. Foramsulfuron, tembotrione and S-metolachlor were less inhibitory at 25 than at 15 °C, but the temperature had no influence on reduction of mycelial growth at pyridate and fluazifop-P-butyl. Of the herbicides tested, pyridate and fluazifop-P-butyl showed less adverse effects and are probably compatible with B. bassiana in the field. However, extensive field studies complemented by parallel laboratory experiments should consider assessing the interaction between selected herbicides and B. bassiana isolates to evaluate their ecological impact in cropped environments.
In the present study, the genetic relationships and ergot-alkaloid production of the fungus Claviceps purpurea on grasses were investigated, to determine any associations between grass host ...specificity, ergot-alkaloid production, and geographic origin. C. purpurea sclerotia were obtained from wild and cultivated grasses along a 300-km climatic gradient, from sub-Mediterranean to continental climates. Twenty-one infected grass samples provided 39 sclerotia for analysis of the ergot alkaloids ergometrine, ergosine, ergotamine, ergocornine, ergocryptine, and ergocristine, and their "-inine" epimers, using liquid chromatography-tandem mass spectrometry. C. purpurea ribosomal DNA underwent molecular classification to determine any grass host or geographic specificity of ergot-alkaloid composition for the different operational taxonomic units. Molecular analysis of sclerotia ribosomal DNA showed three genetic groups, with some associations with specific grass host taxonomic groups. The ergot-alkaloid composition data were in agreement with the data obtained by molecular methods. The most frequent ergot-alkaloid epimers were ergocristine, and ergosine. The total ergot-alkaloid concentrations in sclerotia varied from 59 to 4,200 mg kg
, which corresponds to 0.059 to 4.2 mg kg
in animal feed (assuming ergot alkaloids at 1,000 mg kg
sclerotia). Therefore, grasses can be associated with significant levels of ergot alkaloids. In addition, the ergot-alkaloid compositions of C. purpurea sclerotia can be different for infections with different C. purpurea genetic groups, because these show different ergot-alkaloid compositions.
PDF
