The effect of strong microwave electric field radiation on: (2) wheat (Triticum aestivum L.) seed germination and sanitation

Abstract The seeds of the winter and spring wheat (Triticum aestivum L.) were subjected to a strong microwave electric field (SMEF) generated in a high power magnetron generator, working in a pulsed mode. Seed samples with different moisture contents (12, 15 and 18 %) were treated at the band 2.6, 5.7 and 9.3 GHz at 5, 10 and 20-minute exposures. Seed germination energy (GE), germination (G), abnormally germinated seeds (AG), germination index (GI) and seedling vigour index (SVI) were tested. The effect of SMEF on Tilletia caries infestation, plant productivity and seed sanitation was also explored. Seed treatment with SMEF did not sufficiently effect on winter wheat seed GE and G; however, the increase in AG and reduction in GI and SVI were observed. The negative effect on GI and SVI increased when seeds with higher humidity were treated. Treatment of winter wheat cv. 'Kovas' seeds, artificially inoculated with Tilletia caries, with SMEF showed a trend towards reduction of bunt infected ears. Seed treatment with SMEF stimulated grain yield increase and the bands 2.6 GHz for 20 min, 5.7 GHz for 10 min and 9.3 GHz for 5 and 10 min induced an increase in grain number and grain weight per ear. The efficacy of the chosen SMEF bands and exposition time on winter and spring wheat seed sanitation were contradictory. The SMEF treatment against wheat seed borne pathogens such as Phaeosphaeria nodorum (causal agent of Stagonospora glume blotch), Pyrenophora tritici-repentis (causal agent of tan spot) and Fusarium spp. (causal agents of seedling and adult plant foot and root rots and Fusarium head blight) gave conflicting and inconsistent efficacy results. The composition of most frequently isolated Fusarium species on SMEF treated winter wheat seeds was pertained to SMEF bands and exposition time

The infestation of winter rye and triticale grain with Fusarium fungi as affected by fungicide use

Experiments conducted at the Lithuanian Institute of Agriculture in 2004–2005 were designed to investigate the contamination of winter rye cv. ‘Duoniai’ and triticale cv. ‘Tornado’ grain with fungi of genus Fusarium and mycotoxins produced by them as affected by the spray-applications of the crops with the fungicides propiconazole, tebuconazole, and azoxystrobin at the beginning of anthesis (BBCH 63). Having analysed winter rye and triticale grain samples for Fusarium species composition ( Fusarium avenaceum (Fr.) Sacc, F. sporotrichioides Sherb., F. poae (Peck) Wollenw, F. culmorum (W. G. Sm.) Sacc., F. graminearum Schwabe, F. solani (Mart.) Sacc., F. incarnatum (Desm.) Sacc . F. sambucinum Fuckel) were identified in rye grain — ( F. culmorum (W. G. Sm.) Sacc., F. poae (Peck) Wollenw., F. heterosporum Nees) — in triticale grain. The grain samples from winter rye plots sprayed with azoxystrobin were the most heavily affected by Fusarium (42.5%) and the highest contents of DON (691 μg kg −1 ) and T-2 toxin (153.6 μg kg −1 ) were identified in them. Tebuconazole reduced the amount of Fusarium -affected grain in rye and triticale, but did not have any effect on mycotoxin production in rye. The grain of triticale not sprayed with fungicides was more heavily contaminated with DON (427 μg kg −1 )

A comparative study of strobilurin and triazole treatments in relation to the incidence of Fusarium head blight in winter wheat, grain quality and safety

Field experiments were conducted over 3 years to assess the effects of fungicides (F) containing strobilurins (alone and in mixture with morpholine, triazoles) and triazoles (epoxiconazole or propiconazole) on winter wheat ‘Zentos’ grain quality, incidence of Fusarium head blight (FHB) in the field, grain contamination with fungi and mycotoxins. The effect of strobilurins and triazoles on the parameters tested was more dependent on the weather conditions of the growing season than on the F applied. The incidence of FHB was low in 2002 and 2003, but high in 2004. Averaged data suggest that strobilurin treatments decreased the level of FHB. In 2002, grain contamination with fungi was lower than in 2003 and 2004. The data on the impact of fungicides on post-harvest grain infection with Fusarium spp. and contamination with mycotoxins deoxynivalenol (DON), zearalenone (ZEN) and T-2 were controversial. The fungicides only insignificantly affected protein and gluten concentration in grain, as well as sedimentation and falling number. All grain quality components were especially dependent on the year (significant at P<0.01). However, fungicide application significantly, at P<0.01, increased grain protein and gluten yields: they were higher for the strobilurin-treated plots (with a small exception) than for the untreated and those treated with propiconazole

Evaluation of eyespot incidence and structure of Oculimacula spp. population in winter rye in Lithuania

Abstract Eyespot of rye, caused by two fungal pathogens Oculimacula yallundae and O. acuformis, is widespread throughout many cool and wet cereal growing regions. The study was aimed to estimate eyespot incidence in winter rye crops in three agro-ecological zones of Lithuania, and to quantify eyespot disease causal agents O. yallundae and O. acuformis in the population using the real-time polymerase chain reaction (RT PCR) method. During the 2008-2012 periods, 69 winter rye fields were surveyed and eyespot-affected stems were identified in 92.7% of the crops surveyed. The incidence of eyespot in winter rye crops varied from 8.0% to 82.7% depending on the year and location. The average disease incidence in the reviewed crops was 26.0%. The highest incidence of eyespot averaging 34.0% was identified in the winter rye crops of the Middle Lowland zone. Both eyespot causal agents O. yallundae and O. acuformis were often found to co-exist on the winter rye stems. In the majority of the winter rye crops tested, O. acuformis was predominant in the Oculimacula spp. population. In most cases, O. yallundae was identified only at trace-level concentrations

Sensitivity of Mycosphaerella graminicola isolates to demethylation-inhibiting (DMI) fungicides

Abstract Mycosphaerella graminicola (Fuckel) J. Schröt. (anamorph Zymoseptoria tritici (Desm.) Quaedvlieg &amp; Crous) causes Septoria leaf blotch disease of wheat. The disease can be responsible for yield losses of 30-50% and, when severe, requires management with a fungicide. Single picnidia isolates collected from different locations of Lithuania were tested in vitro for sensitivity to demethylation-inhibiting (DMI) fungicides epoxiconazole, cyproconazole and prothioconazole. Fungicide concentrations were chosen from the proposed Fungicide Resistance Action Committee (FRAC) methods. Microtitre plates with 96-wells were inoculated with suspensions of pycnidiospores taken from single pycnidia of leaves. In total, 196 isolates from 34 locations were tested over the three experimental years (2009)(2010)(2011). The results showed reduced sensitivity of M. graminicola isolates to epoxiconazole and cyproconazole. The average EC 50 values over three experimental years for epoxiconazole varied between 1.02 and 3.15 mg l -1 , for cyproconazole -1.51 and 10.66 mg l -1 . The sensitivity to prothioconazole of 64 isolates from 13 locations (2011) ranged from 0.43 to 32.28 mg l -1 . Results of field experiments (2007)(2008)(2009)(2010)(2011) showed that fungicides epoxiconazole and prothioconazole significantly reduced the area under the disease progress curve (AUDPC) values of Septoria leaf blotch compared with untreated plots in winter wheat. In most cases, a single fungicide application significantly increased grain yield and a thousand grain weight weight