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Salicylic acid (SA) applied at concentrations from 1–10 µg·ml⁻¹ to germinating seeds of 8 barley cultivars reduced the disease rating of seedlings. Seedlings of barley not treated with SA and inoculated with Fusarium culmorum exhibited disease rating of root on avarage 76 %. Seedlings treated before inoculation with solution of SA 1, 2, 5 and 10 µg/ml exhibited significantly lower disease rating: on average 66, 58, 44 and 38 %. Disease score of leaf decreased in similar extent: from 30 % to 20, 11, 7 and 0 %.
When 136 samples of dying carrot seedlings from several fields were analyzed Alternaria radicina proved to be the most common seedling pathogen (41 %), followed by some Fusarium species (27 %, mostly F. avenaceum).The less common seedling pathogens were Pythium spp. (13 %), Phoma spp. (2.5 %) and Botrytis cinerea (1.4 %). Some other fungi (Bipolaris sorokiniana, Sclerotinia sclerotiorum, Stemphylium botryosym and Ulocladium consortiale) were found in less than 1 % of seedlings examined.
Badano podatność 4 męskosterylnych liniii pszenżyta, 5 rodów i odmian ojcowskich oraz 20 mieszańców F1 otrzymanych z krzyżowania tych form w układzie czynnikowym, na zgorzel siewek wywołaną przez Fusarium culmorum. Ziarniaki inokulowano izolatem IPO348-01 pochodzącym z Instytutu Ochrony Roślin w Wageningen w Holandii. Pojedyncze izolaty F. culmorum hodowano na pożywce PDA (Potatoe Dextrose Agar-Sigma) na płytkach Petriego. Inkubację prowadzono w stałych warunkach laboratoryjnych przez 7 dni w temperaturze 22°C. Mieszańce F1 charakteryzowały się średnio nieco mniejszym porażeniem liści niż rodzice i podobnym porażeniem korzeni. Wykazano istotną korelację między stopniem porażenia liści u mieszańców a ogólną wartością kombinacyjną (GCA) rodziców, co świadczy o możliwości typowania komponentów rodzicielskich pod kątem większej odporności na podstawie GCA. Porażenie siewek zależało jednak w większym stopniu od swoistej wartości kombinacyjnej (SCA) par rodzicielskich niż GCA rodziców. Współczynniki korelacji między porażeniem liści i korzeni u mieszańców a efektami SCA par rodzicielskich były dodatnie i statystycznie istotne (odpowiednio r = 0,642** i 0,881**). Wyniki wskazują, że poziom odporności u mieszańców był kształtowany także w wyniku nieaddytywnego działania genów i sama wartość GCA rodziców może być zawodna w przewidywaniu ich odporności na F. culmorum.
Rhizobacteria isolated from cotton roots exhibiting antagonism towards seedling blight and leaf blight of cotton were tested for their efficiency against the insect pest American bollworm (Helicoverpa armigera). The bioformulation developed using Bacillus subtilis (isolate DGL9) + chitin was found to be detrimental to the developmental stages of H. armigera (larva, pupa and adult) by causing larval mortality, pupal and adult malformation with reduced adult emergence. Generally, the larvae exhibited antifeeding behaviour when fed on bolls collected from rhizobacterial treatments. Hence, the developmental stages were altered leading to early pupation. Further, the efficacy of the isolate DGL9 was confirmed by culturing the bacteria in a suitable medium and incorporating the cell suspension and supernatant obtained form the broth culture in larval diet. The larvae fed to the diet exhibited defective developmental stages which was more significant in case of diet incorporated with supernatant. The percentage of pupal malformation, adult emergence and adult malformation was high at 96 h of incubation with the supernatant.
The investigations were done between 1990-1994. Seedlings collected from 120 plantations were evaluated. The fungi responsible for seedling damping-off occurrening most often were Alternaria spp., Fusarium spp. and Pythium spp. isolated from 46,3, 32,2 and 16,6% of infected plants, respectively. The most important pathogens were A. petroselini which infected 33% of seedlings and A. radicina - 11%. Among Fusarium species the most common was F. avenaceum, comprising 61% of total Fusarium isolates. The next were following: F. culmorum - 21%, F. solani - 12,6% and 3% for both F. equiseti and F. oxysporum. Damping-off of seedlings was also caused by the other fungi but they were noted in low intensity. Among them were following: Phoma spp., A. alternata and Rhizoctonia solani on 2,8; 2,3 and 1,2% of tested seedlings, respectively. The species: Sclerotinia sclerotiorum, Botrytis cinerea, Bipolaris sorokiniana and Septoria petroselini were isolated in total from 0,9% of seedlings. Drechslern biseptatu and Stemphylium botryosum caused seedling damping-off sporadically.
Acta Agrobotanica
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2002
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tom 55
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nr 1
255-263
Seed treatment of root parsley was done to protect Petroselinum sativum seedlings against damping off. Fungicides used as seed dressers were applied in 3 doses: 3, 5 and 10 g/kg. Seeds were treated with 7 dressers (Table 1) used separately and in mixture with 3 g/kg ofRovral50 WP (50% iprodione) and 1 g/kg of Apron 35 SD (35% metalaxyl). Two seed samples of Berlińska cultivar were used: [rrst sample was strongly infected by Alternaria petroselini and A. radicina both 27,6% and .:a1so by Fusarium spp. 5,4% (Test I), and second sample revealed lower percentage of infection 4,6% and 1,2%, respectively (Test m. The experiments were conducted under laboratory, glasshouse and field conditions. Complete seedlings protection a11 experiments was achieved for treatments when fungicide mixture was used the highest dose (10 g/kg). Decrease of fungicides concentrations were connected with lower effectiveness of disease control. No phytotoxic effects of the tested fungicide mixtures were observed under the glasshouse or field conditions.
The research was conducted in the years 1998-2001. The aim of the research was to determine the hea1th of the field pea ev. Kormoran grown in four various crop rotations and to determine the patogens causing the root-rot. On the pea it plants the following diseases were found: root rot (complex of fungi), ascochyta blight (Ascochyta pisi, Phoma pinodella, Mycospaerella pinodes) and fusarium foot rot (Fusarium spp.). All the diseases occurred in the highest intensity on the pea cultivated in three-field erop rotation without manure. The weather conditions affected the intensity of the diseases. From the roots of seedlings with the symptoms of root rot 44.7% of fungi with pathogenie potential in relation to pea were obtained. The most commonly isolated were Fusarium oxysporum (26.7% of all isolates), Rhizoctonia solani (10.7%), F. solani (3.3%), F. avenaceum (2.7%) and F. equiseti (1.3%). From the infected foot necks, 55.3% of potential pathogens of field pea were obtained. Among the isolates the most commonly found was F. oxysporum (31.1 % of all isolates).er fungi of the Fusarium genus constituted 15.4% of isolates, R. solani 7.0%, d Sclerotinia sclerotiorum 1.8%.
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