Influence of fungicide protection on health status and yielding of winter wheat

The aim of the study was the effect of different chemical protection of winter wheat on occurrence of fungal diseases of stem base, leaves and yield as well. In 1999-2001 cultivars Roma and Kobra were tested in Lisewo and Wielgłowy in northern Poland. There was one fungicide treatment with kresoxim-methyl and epoxyconazole during phase 39—49 and two treatments, first with kresoxim-methyl + epoxyconazole in phase 32 and the second with tridemorf + epoxyconazole in phase 51-55. In 2002-2004 the experiment was continued in Wielgłowy on cultivar Kobra with protection combinations as follows: first treatment with kresoxim-methyl + epoxyconazole in phase 39-49, and the next ones with tridemorf + epoxyconazole or dimoksystrobine + epoxyconazole in phase 51-55. The highest infection was observed on cv. Kobra. Among pathogens isolated from infected stem bases, Fusarium spp. predominated, while Rhizoctonia spp. and Mollisia yallundae were less numerous. Powdery mildew was observed in relatively low or trace intensity, but complex of necrotic spots on leaves was noticed in high intensity. High occurrence of Mycosphaerella graminicola,. Phaeosphaeoria nodorum and Pyrenophora tritici-repentis as well as Fusarium spp. was observed. Fungicide treatments were very effective in reducing occurrence of the investigated pathogens. The area of upper leaves without disease symptoms (GLA) was significantly higher in combinations with fungicides.Badano wpływ zróżnicowanej ochrony chemicznej na nasilenie występowania chorób grzybowych podstawy źdźbła i liści pszenicy ozimej oraz jej plonowanie. W Lisewie k/Malborka i Wielgłowach k/Tczewa testowano w latach 1999-2001 odmiany Roma i Kobra. Zastosowano jeden zabieg krezoksymem metylowym + epoksykonazol w fazie (39-49) oraz dwa zabiegi, pierwszy krezoksymem metylowym + epoksykonazol w fazie 32, a drugi tridemorf + epoksykonazol w fazie 51-55. W latach 2002-2004 kontynuowano doświadczenie w Wielgłowach na odmianie Kobra, z następującymi wariantami ochrony - pierwszy zabieg krezoksymem metylowym + epoksykonazol w fazie 39-49, a następne tridemorf +epoksykonazol lub dimoksy strobiną+ epoksykonazol w fazie 51 -5 5. Najsilniej porażona była odmiana Kobra. Z porażonych źdźbeł izolowano głównie patogeny z rodzaju Fusarium, rzadziej Rhizoctonia spp. i Mollisia yallundae. Mączniak prawdziwy występował w stosunkowo niewielkim lub śladowym nasileniu. W dużym nasileniu natomiast wystąpił kompleks nekrotycznych plamistości na liściach. Zaobserwowano duży udział M. graminicola, S. nodorum i P. tritici-repentis, a także grzybów z rodzaju Fusarium. Zastosowane zabiegi okazały się bardzo skuteczne w ograniczeniu porażenia przez badane patogeny. W kombinacjach z fungicydami istotnie większa była powierzchnia górnych liści bez objawów porażenia (GLA)

Fusarium head blight (FHB) and Fusarium spp. on grain of spring wheat cultivars grown in Poland

Eighteen spring wheat cultivars, recommended for commercial production in northern Poland, were assessed for Fusarium head blight (FHB) in natural non-epidemic conditions, from 2011 to 2013. Assessment was based on FHB incidence (proportion of heads with symptoms), disease severity (DS; proportion of bleached spikelets per head), proportion of Fusarium damaged kernels (FDK), and spectrum of Fusarium spp. colonising the kernels. Fusarium head blight incidence and DS often differed significantly among cultivars and years. There was a strong positive correlation between FHB incidence and DS. Fusarium head blight incidence and DS were not correlated with the June–July temperatures, and were only occasionally correlated with the total June–July rainfall. There was a weak positive correlation between FHB incidence and proportion of FDK. There was a strong positive correlation between DS and proportion of FDK. The cultivar affected colonisation of kernels by Fusarium spp. Fusarium poae was the FHB pathogen isolated most often. Fusarium poae colonised 6.0% of the kernels, on average, but up to 12.0% on individual cultivars. Other Fusarium species were less frequent: F. avenaceum in 5.6% of kernels, F. culmorum in 5.3%, F. tricinctum in 2.8%, F. graminearum in 1.5%, and F. sporotrichioides in 1.2%. Fusarium equiseti occurred sporadically. The importance of F. poae in the FHB complex is emphasised. All cultivars expressed ‘moderate FHB resistance’ if evaluated according to FHB incidence. Cultivars Arabella, Izera, Kandela, Monsun, Ostka Smolicka, and Struna expressed ‘moderate susceptibility’, and Bombona, Hewilla, Katoda, KWS Torridon, Łagwa, Nawra, Parabola, Radocha, SMH 87, Trappe, Tybalt, and Waluta expressed ‘susceptibility’ if evaluated by the proportion of FDK. Cultivars differed within the ‘moderately resistant’, ‘moderately susceptible’, and ‘susceptible’ categories. Cultivars Arabella, Izera, Kandela, Monsun, Ostka Smolicka, and Struna were the most promising and their resistance traits may be useful in FHB management