Fusarium infected grain removal efficacy in cleaning wheat grain prior to milling

Abstract Four wheat cultivars with different levels of tolerance to Fusarium head blight (FHB) were grown in small plots and were inoculated with spores of Fusarium fungi during the anthesis. The harvested grain was cleaned by a special cleaner which separated it in 4 size fractions: F1 ->2.4 mm, F2 -2.0-2.4 mm, F3 -1.8-2.0 mm, F4 -<1.8 mm. These were further divided manually in four sub-fractions according to the rate of FHB symptom expression, i.e. grain without any visible symptoms, grain with changes in colour without changes in shape, grain with changes in colour and moderate changes in shape or size, and heavily infected malformed grain. Deoxynivalenol (DON) content in grain of different fractions was determined by high-performance liquid chromatography with UV detection (HPLC-UV) analysis. Comparisons between initial DON content before cleaning and DON content in individual fractions after cleaning were made. The cleaning efficacy (rate of DON content reduction) due to the cleaning and separating of grain in size fractions was higher in semi-tolerant and susceptible cultivars than in FHB tolerant cultivar. Due to the low cleaning efficiency, cleaned grain of tolerant cultivar (without any symptom of FHB), contained twice more DON (870-1350 µg kg -1 ) than cleaned and apparently healthy grain of semi-tolerant cultivar (160-570 µg kg -1 ); its DON content was comparable to that of the susceptible cultivar (905-1140 µg kg -1 ). Our results indicate that FHB tolerant cultivars may contain a high proportion of grain which is apparently healthy, but contains excessive DON levels. Such tolerant cultivars can contribute a lot to minimisation of yield loss caused by FHB, yet they may present a potential health hazard of organic whole-grain flour produced in non-industrial grain processing systems

Long-Term Control of Hedge Bindweed (Calystegia sepium L.) with Single, Tank Mixture, and Sequential Applications of Glyphosate, 2,4-D, and Dicamba

Hedge bindweed (Calystegia sepium L.) is a widespread troublesome perennial weed species that has strong rhizome regenerative capacity. Four pot trials with randomised, complete block designs were conducted in 2015 to evaluate long-term control of hedge bindweed using individual, tank mixture, and sequential applications of selected herbicides. Two different formulations of N-(phosphonomethyl) glycine (glyphosate; isopropylamine, trimesium salts) were applied at 2000 g active ingredient (a.i.) ha−1. Additionally, two synthetic auxins were applied as 3,6-dichloro-2-methoxybenzoic acid (dicamba) at 500 g a.i. ha−1 and the dimethylamine salt of (2,4 dichlorophenoxy)acetic acid (2,4-D) at 1000 g a.i. ha−1. Tank mixtures and sequential applications (12/24 h separation) of these different herbicides were also included. Long-term control of hedge bindweed, Calystegia sepium L., growth was evaluated 8 months after treatments, as comparisons of shoot and rhizome growth (biomass) between untreated and treated plants. There were no differences between the two formulations of glyphosate alone, with shoot and rhizome biomass reductions of 83% and 42%, respectively. Dicamba alone inhibited shoot and rhizome biomass by 86% and 67%, respectively. By itself, 2,4-D provided the greatest reductions in shoot and rhizome biomasses, 93% and 79%, respectively. Antagonism was seen in the tank mixtures of glyphosate and dicamba or 2,4-D. Tank mixtures were generally comparable to treatments of glyphosate alone, and were less effective compared to dicamba or 2,4-D alone. The greatest reduction of bindweed rhizome biomass was for sequential glyphosate trimesium salt followed by 2,4-D 12 h later, thus showing significantly greater efficacy over glyphosate isopropylamine salt (94% vs. 84%; p ≤ 0.05). These data for reductions of the growth of the rhizome biomass show that the sequential application of glyphosate followed by 2,4-D significantly improves long-term control of hedge bindweed

Management of trichothecene mycotoxins (deoxynivalenol and nivalenol) in non-industrial cereal production and processing chain

Da bi opravili analizo spreminjanja vsebnosti trihotecenskih mikotoksinov deoksinivalenol (DON) in nivalenol (NIV) v pridelovalni in predelovalni verigi, smo pšenico pridelovali v poljskih poskusih na majhnih parcelicah, jo poželi in očistili z različnimi napravami za čiščenje, nato smo jo zmleli v različne vrste moke in nazadnje spekli kruh. Izvedli smo tudi poskus skladiščenja moke v različnih skladiščnih razmerah. Štiri kultivarje pšenice z različno stopnjo odpornosti (tolerantnosti) na okužbe z glivami, ki povzročajo fuzariozo klasa (FHB), smo gojili v poljskih poskusih. Med cvetenjem smo pšenico okužili s sporami gliv iz rodu Fusarium. Požeto zrnje smo prečistili s pomočjo posebne čistilne naprave, ki je ločila zrnje v štiri velikostne razrede (F1 > 2,4 mm, F2 2,0–2,4 mm, F3 1,8–2,0 mm, F4 2.4mm, F2 2.0–2.4mm, F3 1.8–2.0mm, F4 < 1.8mm). All of the four grain size fractions were divided manually further in 4 sub-fractions according to the rate of FHB symptom expression (grain without any visible symptoms, grain with changes of colour without changes of shape, grain with changes in colour and moderate changes in shape or size and heavily infected malformed grain). Deoxynivalenol (DON) content in grain of different fractions was determined by HPLC-UV analysis. A comparisons between initial DON concentration before cleaning and DON concentration in individual fractions after cleaning were done. The cleaning efficacy (rate of DON concentration reduction) due to the cleaning and separating of grain in size fractions was higher in semi tolerant and susceptible cultivars than in FHB tolerant cultivar. In consequence of the low cleaning efficiency, cleaned grin of tolerant cultivar, without any symptom of FHB, contained twice more DON (870––1350 µg/kg) than cleaned and visually healthy grain of semi tolerant cultivar (160–570 µg/kg) and contained comparable amount of DON as susceptible cultivar (905–1140 µg/kg). Results of trial demonstrate the existence of FHB tolerant cultivar which can bear a high portion of visually healthy grain containing high levels of DON. That grain can not be removed during the standard grain cleaning process. Such tolerant cultivars can contribute a lot to minimisation of yield loss due the FHB, yet they are not suitable for utilisation in the whole-grain wheat flour production. Experiment with milling and baking has showed, that this procedures significantly affect retention of trichothecene toxins (DON and NIV). Impact of three milling techniques (industrial roller-grinder – IRG, grain hammer crasher – IHC, traditional millstone –OMS) and two baking techniques (industrial oven, traditional ceramic stove heated by wood) was observed. Initial values of DON and NIV in grain sample (2500 kg) ranged from 1400–1900 µg/kg and 130–200µg/kg, respectively, and were after processing 310–370µg/kg and <50–70µg/kg in standard industrial flour, 1060–1400 µg/kg and 60–87 µg/kg in industrial wholegrain flour and 1100–1770 µg/kg and 80–95 µg/kg in traditional wholegrain fluor, respectively. Six diferent types of bread samples were prepared from this flours and analysed. The average reduction in DON concentration after baking (70 min. at 195–235 °C) was 47.2 % for bread baked in the industrial oven and 48.7 % for bread baked in the ceramic stove. Concentrations of DON in bread from industrial flour baked in industrial oven were under 500 µg/kg, but values in bread prepared from traditional wholegrain flour were higher (850–950 µg/kg). In the flour storage experiment, we didn’t notice any significant differences between storing flour at 10 °C and 25 °C. After 120 days of storage, the concentrations of DON and NIV decreased between 0 % and 29 % compared to the initial values, depending on the combination of experimental factors. The greatest decrease in mycotoxin concentration was observed in the IHC and OMS flours packaged in paper bags and stored at 25 °C. The smallest decrease in mycotoxin concentration was observed in the IRG flours packaged in sealed plastic bags and stored at 10 °C. Statistical analysis showed that the level o

The effect of cultivation practices on agronomic performance, elemental composition and isotopic signature of spring oat (Avena sativa L.)

The present study investigated the effects of cultivation practices on grain (oats) yield and yield components, such as straw yield, harvest index, thousand kernel weight, and plant lodging. In addition, multi-element composition and isotopic signature (δ(13)C, δ(15)N) of the oat grains were studied. The spring oat cultivar ‘Noni’ was grown in a long-term field experiment during 2015–2020, using three management practices: control without organic amendment, incorporation of manure every third year and incorporation of crop residues/cover crop in the rotation. Synthetic nitrogen (N) (0, 55, 110 and 165 kg/ha) was applied during oat development in each system. Multi-element analysis of mature grains from two consecutive years (2016 and 2017) was performed using EDXRF spectroscopy, while stable isotope ratios of carbon (C) and nitrogen (N) were obtained using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA/IRMS). The results show how cultivation practices affect yield components and isotopic and elemental signatures. Increasing the N rate improved both the oat grain and straw yields and increased susceptibility to lodging. The results show how the elemental content (Si, Ca, Zn, Fe, Ti, Br and Rb) in the oat grains were influenced by intensification, and a noticeable decrease in elemental content at higher N rates was the result of a dilution effect of increased dry matter production. The mean δ(15)N values in oat grains ranged from 2.5‰ to 6.4‰ and decreased with increasing N rate, while δ(13)C values ranged from −29.9‰ to –28.9‰. Based on the δ(15)N values, it was possible to detect the addition of synthetic N above an N rate of 55 kg/ha, although it was impossible to differentiate between different management practices using stable isotopes

Chemical alterations of grain surface by cold plasma technology

Cold plasma (CP) has a great potential for decontamination or improvement of grain germination. However, disputing results have been reported, as plasma treatment can affect species and varieties of grains in different ways. The differences may be due to the chemical composition of grain pericarps, the structure of the grains and metabolic response mechanisms. CP treatment decreased grain germination rate, speed and activity of α-amylase of buckwheat grains. Such effects on both varieties of wheat grains were present after longer exposure to plasma. Lipid peroxidation was highest in buckwheat grains, whereas wheat grains were less affected. Plasma-treated Gorolka variety exhibited a low level of lipid peroxidation, no different to untreated grains, compared to Primorka grains, where longer treatment triggered higher levels of lipid peroxidation. The response of grains to CP treatment depends on the chemical and structural properties of grains pericarp, as well as plant tolerance to certain abiotic conditions

Evaluation of the field efficacy of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) and synthetic insecticides for the control of western corn rootworm larvae

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera, Chrysomelidae), is an important insect pest of maize in North America and Central and Eastern Europe. In Central Europe, the larvae emerge in May and its three instars feed intensively on maize roots in June, causing plant lodging that leads to a loss of economic yield. A three-year field experiment (2016–2018) was conducted to compare the effectiveness i) of soil-applied granular insecticide based on the active ingredient tefluthrin, ii) of maize seeds dressed with thiacloprid, and iii) entomopathogenic nematodes Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae, product Dianem) against WCR larvae. An additional treatment with alcohol ethoxylate (i.e., soil conditioner) mixed with entomopathogenic nematodes was performed in 2017 and 2018 to check for any increase of entomopathogenic nematodes’ effectiveness. Field tests were carried out in two fields infested naturally with a WCR pest population, one in Bučečovci (Eastern Slovenia) and the other in Šmartno pri Cerkljah (northern Slovenia), exhibiting dissimilar pedo-climatic conditions and soil pest densities. The treatments were performed in five replicates per experiment in each year. The efficacy of the treatments was very similar at both locations, despite the approximately five-fold lower WCR soil pest densities in northern than in eastern Slovenia, as well as being constant over time. The largest number of WCR beetles was observed in the negative control, followed by that of beetles subjected to thiacloprid treatment (insignificant decrease taking into account the entire three-year dataset). Treatments with tefluthrin (44.1 ± 11.7%), H. bacteriophora (46.2 ± 7.4%), and H. bacteriophora + alcohol ethoxylate (49.2 ± 1.8%) significantly decreased the numbers of emerging beetles. Treatments of thiacloprid, H. bacteriophora, and H. bacteriophora + alcohol ethoxylate additionally led to significantly increased maize plant weights. Furthermore, entomopathogenic nematodes were able to persist in maize fields for almost five months at both experimental locations in silty and sandy loam soils. It was concluded that the control of WCR larvae in maize using the entomopathogenic nematode H. bacteriophora is as effective as a tefluthrin treatment, and could thus offer a sustainable Diabrotica v. virgifera biological control management option in Europe

Effectiveness of different control measures against western corn rootworm larvae Diabrotica virgifera virgifera LeConte, 1868

The Western Corn Rootworm (WCR), Diabrotica virgifera virgifera LeConte, 1868, [Coleoptera, Chrysomelidae], whose larvae cause damage to maize roots, is an important economic insect pest in America and Europe. Its larvae are usually controlled by granular soil insecticides or insecticide-treated seeds. Biological control options, such as entomopathogenic nematodes (EPN) have played an important role as an alternative for synthetic chemical insecticides. Therefore, for the WCR larvae control we compared the effectiveness of inundative biological control on the basis of EPN Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae); (commercial product Dianem®) and the conventional insecticides Force 1.5 g (active substance tefluthrin) from the group of synthetic pyrethriods and Sonido (active substance thiacloprid) from the group of neonicotinoids. Field experiments were carried out at geographically different locations under different population pressure of the insect pest in a), Bučečovci (Prlekija; Eastern Slovenia) and b), Šmartno (Gorenjska: northern Slovenia). The differences between the treatments were very similar at both locations; although the population of WCR in Gorenjska was approximately 5-fold lower than in Prlekija. The highest number of WCR beetles was caught in the negative control, followed by the product Sonido, Force and Dianem®, in decreasing order. Statistical analysis showed that only in the treatment where EPN were used, significantly less WCR was caught than in the control. The results of the WCR larvae control in maize using Heterorhabditis bacteriophora are comparable to published literature. However, the weather conditions in the 2016 trial were very favorable for the development and survival of EPN in the soil.</p