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From 2008 to 2010 the levels of sugar beet seedlings infection caused by Rhizoctonia solani were compared in laboratory tests. Seven sugar beet lines were tested: H56, H66, S2, S3, S4, S5 and S6 as well as three control cultivars: Carlos, Esperanza and Janosik. Sugar beet lines with tolerance to rhizoctoniosis and cultivars without tolerance were infected artificially by R. solani isolates: R1, R28a and R28b. These isolates belong to the second anastomosis group (AG), which is usually highly pathogenic to beet roots. The aim of the experiment was to test whether the tolerance of sugar beet genotypes to R. solani AG 2 prevents both root rot, and damping-off of seedlings, induced by the pathogen. Sugar beet lines tolerant to brown root rot in laboratory tests were significantly less sensitive to infection of the seedlings by R. solani AG 2 isolates in comparison to control cultivars. Rhizoctonia solani AG 2 isolates demonstrated considerable differences in pathogenicity against seedlings of sugar beet lines and cultivars. The strongest infection of sugar beet seedlings occurred with the isolate R28b. The greatest tolerance to infection by AG 2 isolates was found for the S5 and S3 breeding lines.
Similary to other fungal species of the genus Alternaria, Alternaria radicina is a major pathogen that infects both the aboveground and underground parts of carrot plants. Changes in the concentrations of phenolic compounds are observed in infected carrot plants. Carrot seedlings were inoculated with the most pathogenic isolates of Alternaria radicina selected in a laboratory test. A phytopathological analysis was performed to determine the health status of carrot plants. The concentrations of phenolic acids in petioles were determined four weeks after inoculation with A. radicina and at harvest. The results of a greenhouse experiment revealed more severe disease symptoms on carrot plants cv. Koral inoculated with A. radicina isolates, compared with cv. Bolero. The content of the predominant phenolic acid (chlorogenic acid) was found to decrease in the leaf stalks of carrots cv. Koral inoculated with A. radicina. A statistically non-significant increase in chlorogenic acid levels was noted in the leaf stalks of carrots cv. Bolero in the experimental and control groups.
Old avenues, or alleys of trees, form an important part of the cultural landscape. They used to be planted mainly in gardens and parks; later, they started playing an even more important role, particularly in the open areas, and within urban landscapes. Nowadays, they are frequently regarded as inconvenient formations, which exert a negative impact on traffic and impede road construction. However, it is is worth bearing in mind that avenues play a number of crucial functions in terms of climate, ecology and aesthetics, and as such they deserve particular care. The article is devoted to the linden trees planted in an avenue layout along the Nałęczowska street in Lublin town in Poland. The layout currently consists of 85 individual trees in varying health condition, that is, 35% of healthy trees, nearly half exhibiting signs of reduced vitality, and 16% in the state of advanced decay.
The article presents the composition of the dendroflora in a historic park surrounding the castle in Szamotuły. In total 465 specimens of woody plants were inventoried (51 taxa of 37 species in 21 families). Most of them were native, angiospermous trees of the apophyte and spontaneophyte groups. In the park there are three specimens of Taxus baccata, registered as natural monuments. The age of more than 100 trees was estimated at over 100 years. The trunk circumference of more than 60 trees exceeded the minimum value assumed as a criterion of categorisation as a natural monument.
A pot experiment on different methods of EM 1 application was conducted in the period 2002–2004. The study was carried out under controlled growth conditions. The experimental factor was the method of EM1 application. Before application, the biological preparation EM1 was propagated as recommended by the manufacturer (Greenland). The health status of the aboveground parts of ‘Ramrod’ pea plants was estimated at the flowering stage. The assessment of pea leaf gas exchange parameters (An, E, Gs, and Ci) was made using a LI-Cor 6400 Portable Photosynthesis System. Soil application of EM1 combined with chemical control contributed to inhibiting Fusarium wilt of pea. Foliar application of EM1 combined with chemical control increased all gas exchange rates of pea leaves. Fusarium wilt of pea insignificantly decreased all gas exchange rates of pea leaves and the number of seeds per pod. The best method of EM1 application was soil treatment combined with chemical control, which increased all yield-related morphometric parameters of pea.
Seed infection with Alternaria spp. is an important source of severe carrot diseases. The aim of the study was to evaluate the effects of carrot seed treatments with acetic acid, grapefruit extract and volatile compounds of fir (Abies alba Mill.) and thyme (Thymus vulgaris L.) essential oils on their germination, vigour and health. Seeds of two samples were soaked for 30 min in 0.5, 1 and 2% acetic acid, 0.5 and 1% Biosept Active (33% of grapefruit extract), or treated for 72 h or 96 h with volatile compounds of fir and thyme oils individually (10 µl), and jointly (5+5 µl). Controls were untreated seeds and seeds soaked in distilled water. Acetic acid effectively controlled A. alternata and A. radicina in both samples, and did not affect adversely seed germination, however, at the highest concentration deteriorated seed vigour. Biosept Active was less effective, however at 1% concentration decreased seeds infestation with A. alternata in sample I, and at concentrations of 0.5 and 1% reduced percentages of seeds infested with A. alternata and A. radicina in sample II. Essential oils treatments in some cases favoured growth of A. dauci and A. radicina.
A field trial was carried out to determine the infection of 19 breeds and 1 cultivar of naked oat with the fungi Erysiphe graminis, Puccinia coronata and Drechslera avenae. The infection with two former species of fungi varied apparently between oat breeds. The degree of infestation had no effect on oat yields. The seeds of oat were used to isolate 25 saprophytic and pathogenic species of fungi. Among the former, Altenaria alternata and Epicoccum purpurascens were dominating. Among the pathogenic species, the most common were fungi belonging to the genus Fusarium, responsible of mycotoxins.
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