Showing papers on "Rhizoctonia solani published in 1974"
TL;DR: Results indicate a non-specific effect of B. subtilis and S. griseus, since they increased growth of plants belonging to two different families, the Gramineae and Umbelliferae, in different soils.
Abstract: The effect of Bacillus subtilis A13 and Streptomyces griseus 2-A24 on the yield of cereals and carrots was studied. The organisms, both antagonistic to Rhizoctonia solani, were applied individually to barley, oats and wheat for sowing at three sites with a known incidence of R. solani. Root disease was not effectively controlled, yet the seed treatments increased grain yield and dry matter production at one site, advanced time of heading at another site and increased tiller number at two sites. Evidence was obtained that the organisms persisted on pericarps in soil for 5 weeks after sowing. In subsequent trials application of B. subtilis and S. griseus in combination with a pellet treatment increased marketable yields of carrots by 48% and 15% respectively over controls. Addition of the organisms to seed without pelleting increased yields by 17% over controls. These results indicate a non-specific effect of B. subtilis and S. griseus, since they increased growth of plants belonging to two different families, the Gramineae and Umbelliferae, in different soils.
146 citations
TL;DR: Production and oxidation of catechin, in response to infection by R. solani, appears to be partially responsible for the resistance of older seedlings, and the resistance may be mediated through the inactivation of fungal PG by oxidized cATEchin.
Abstract: Twelve-day-old seedlings of cotton ( Gossypium hirsutum ) were more resistant than 5- or 6-day-old seedlings to infection by Rhizoctonia solani . At 24 h after inoculation, the concentrations of phenolic compounds, predominantly catechin, were greater in infected 6- or 12-day-old seedlings than in healthy seedlings. The increase was greater in the older seedlings. Seedling extracts inhibited polygalacturonase (PG) activity in proportion to their phenolic content. Catechin oxidized by healthy plant extracts also inhibited PG activity. Production and oxidation of catechin, in response to infection by R. solani , appears to be partially responsible for the resistance of older seedlings. The resistance may be mediated through the inactivation of fungal PG by oxidized catechin.
58 citations
TL;DR: Four inoculants significantly reduced symptoms caused by R. solani and increased grain yield and dry matter of wheat and the magnitude of these differences suggests that biological control and growth stimulation are involved in yield increases.
Abstract: Biological control of Rhizoctonia solani on wheat by seed inoculation with microorganisms was investigated. Initially inoculants were selected from bacteria and actinomycetes isolated from two soils and screened for antagonism to R. solani on agar. Of 148 isolates tested on agar, 96 were antagonistic to R. solani and of these 42 were added to pasteurized soil sown with peppers and inoculated with the pathogen. Seven isolates which controlled disease were screened further as seed inoculants of wheat in pasteurized and field soils inoculated with R. solani. Four inoculants, viz. Streptomyces griseus 2-A24 and three Bacillus subtilis isolates 1-B80, 1-B77 and 1-B68, significantly reduced symptoms caused by R. solani and also increased grain yield and dry matter of wheat. S. griseus 2-A24 and B. subtilis 1-B80 increased grain yield by 30% over controls. The magnitude of these differences suggests that biological control and growth stimulation are involved in yield increases.
48 citations
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39 citations
TL;DR: Plant tissues of low C:N ratio decomposed in soil with the formation of volatiles which increased growth of R. solani in culture and induced pigmentation of its mycelium and melanin or a melaninlike pigment was formed in culture.
Abstract: Plant tissues of low C:N ratio decomposed in soil with the formation of volatiles which increased growth of R. solani in culture and induced pigmentation of its mycelium. The effective plant tissues included vegetable crop residues of C:N <15 and immature grain crop residues (corn, oat, rye,
37 citations
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21 citations
TL;DR: The growth of eighteen isolates of Streptomyces spp.
Abstract: The growth of eighteen isolates of Streptomyces spp. on agars, the osmotic potentials of which were controlled by the addition of various solutes, showed that nine isolates were able to grow at −100 bars and two of these grew at −150 bars. This suggests that the water requirements of soil streptomycetes are almost as diverse as those of soil fungi. In general, linear growth and sporulation declined with decreasing osmotic potential, but one isolate grew optimally at potentials between −5 and −10 bars. Another isolate formed maximum amounts of a water-diffusible antibiotic per unit colony area at potentials between −20 and −35 bars. This appears to be the first report of osmotic potential influencing the production of antibiotic by Streptomyces. The increased antibiotic production at moderate potentials was associated with inhibition of Pythium ultimum, Rhizoctonia solani and a Curvularia sp. by the streptomycete at these potentials on osmotic agar plates. The possible ecological significance of this phenomenon in soil is discussed.
01 Dec 1974
TL;DR: Mancozeb, blasticidin-S, fentin hydroxide, benomyl and edifenphos as foliar sprays effectively control rice blast in the laboratory and field and the search for horizontally resistant varieties is needed.
Abstract: The two major fungal diseases of rice in Nigeria are rice blast (Pyricularia oryzae Cav.) and brown spot (Cochliobolus miyabeanus (Ito and Kuribayashi) Dreschler ex Dastur). The loss in grain yield attributable to these diseases ranges from 11.5–39.6% and 12–43% respectively, Mancozeb, blasticidin-S, fentin hydroxide, benomyl and edifenphos as foliar sprays effectively control rice blast in the laboratory and field. Brown spot is controlled by spraying with thiram, mancozeb or blasticidin-S. A more useful approach to the control of these diseases being adopted in Nigeria is the search for horizontally resistant varieties. Other fungal diseases of rice in Nigeria are the green smut (Ustilaginoidea virens (Cooke) Tak.), basal sheath rot (Rhizoctonia solani Kuhn), sheath blight (Corticium sasakii (Shirai), Matsumoto.), leaf scald (Rhynchosporium oryzae Hashioka and Yokogi), narrow brown leaf spot (Cercospora oryzae Miyake) and bakanae disease, a foot rot caused by Fusarium moniliforme Sheldon. Two s...
TL;DR: Phenylacetic acid was the only good substrate found for specific meta-hydroxylation by R. solani and was slightly inhibited by 10-3M pentachloronitrobenzene although there was no further mycelial growth of the fungus.
Abstract: When phenylacetic acid-1-14C was incubated with mycelial mats of Rhizoctonia solani, the compound was converted to 14C-labeled m-hydroxyphenylacetic acid. This specific meta-hydroxylation by the fungus was slightly inhibited by 10-3M pentachloronitrobenzene although there was no further mycelial growth of the fungus. No hydroxyphenylacetic acid was found after incubation with boiled mycelial mats. Thus, the conversion appears to be enzymatic. Twelve analogues of phenylacetic acid were used to examine substrate specificity of this hydroxylation. Benzoic and phenoxyacetic acids were hydroxylated only at the para-position. Traces of m-hydroxy derivatives were formed from phenylpropionic and trans-cinnamic acids. Many other hydroxy isomers were also detected in these cases. Some other aromatic acids were not converted into their corresponding hydroxy acids. Thus, phenylacetic acid was the only good substrate found for specific meta-hydroxylation by R. solani.
01 Jun 1974
TL;DR: Phytopathogens have characteristics that make them desirable candidates as biological control agents for aquatic weeds: numerous and highly diverse, easily disseminated and self-maintaining, often host-specific, non-pathogenic to animals and capable of limiting populations without eliminating the species.
Abstract: Phytopathogens have characteristics that make them desirable candidates as biological control agents for aquatic weeds: 1. numerous and highly diverse, 2. easily disseminated and self-maintaining, 3. often host-specific, 4. non-pathogenic to animals and 5. capable of limiting populations without eliminating the species. Phytopathogens have been little investigated for the biological control of water weeds. Recent efforts have revealed several diseases with the potential for exerting a degree of control over populations of water hyacinth (Eichhornia crassipes), hydrilla (Hydrilla verticillata) and alligator-weed, (Alternanthera philoxeroides). These include a blight and leafspot of water hyacinth caused by Rhizoctonia solani and Cephalosporium zonatum respectively, a root and crown rot of water hyacinth of unknown cause, a virus-induced stunt of alligator-weed, a Penicillium lysogenic to hydrilla and a pythium-induced blight of hydrilla.
Journal Article•
Journal Article•
TL;DR: Isolations from wilted gram plants were made every month throughout the crop season to obtain fusarium solani, which was obtained from 24.7%, F. oxysporum f.
Abstract: Isolations from wilted gram plants were made every month throughout the crop season. Fusarium solani was obtained from 24.7%, F. oxysporum f. ciceri from 15.5%, Rhizoctonia solani, R. bataticola, Operculella padwickii and F. monili-forme from 8–5, 8–3, 6–2 and 1 • 6% wilted plants respectively.
TL;DR: The rates of synthesis of all RNA species were markedly reduced in the cells of the older mycelium, though turnover rates were not significantly altered.
Abstract: The RNA of the mycelium ofRhizoctonia solani was studied in cells of three different ages. Components corresponding to 25S and 18S, rRNA, and 4S+5S RNA were present in approximately the same ratios in cells of each age. The rates of synthesis of all RNA species were markedly reduced in the cells of the older mycelium, though turnover rates were not significantly altered.
TL;DR: The physiological behavior of large (250–500 microns (μ)) infective and small (50–150 μ) non-infective mycelial fragments (propagules) of Rhizoctonia solani was compared.
Abstract: The physiological behavior of large (250–500 microns (μ)) infective and small (50–150 μ) non-infective mycelial fragments (propagules) of Rhizoctonia solani was compared. Liquid Czapek's medium con...
TL;DR: No correlation was found between calcium applied at an equivalent rate of either 897 or 1,793 kg/ha in an artificial medium and the amount of pod breakdown incited by either Pythium myriotylum or Rhizoctonia solani.
Abstract: No correlation was found between calcium applied at an equivalent rate of either 897 or 1,793 kg/ha in an artificial medium and the amount of pod breakdown incited by either Pythium myriotylum or Rhizoctonia solani. R. solani appeared to be the dominant organism although the isolates tested exhibited a wide range of pathogenicity to peanut pods.
TL;DR: Pre-planting tuber dips of benomyl and thiabendazole were compared as alternatives to organic mercury for Rhizoctonia solani control in two field trials and major differences in level of stem canker between different treatments did not affect yields but produced significant reductions in the second year on an earlier crop.
Abstract: Pre-planting tuber dips of benomyl and thiabendazole were compared as alternatives to organic mercury for Rhizoctonia solani control in two field trials. At suitable rates, all chemicals reduced the stem canker phase of Rhizoctonia solani Kuhn compared with untreated controls. A high concentration of benomyl 0.5% a.i. was necessary to give stem canker control equal to that of 0.015% organic mercury as methoxyethyl mercury chloride. Reducing the benomyl rate to 0.25% a.i. significantly reduced the degree of control. Major differences in level of stem canker between different treatments did not affect yields in the first trial, but produced significant reductions in the second year on an earlier crop.
Dissertation•
01 Jan 1974
TL;DR: Interactions of Pythium myriotylum with several fungi and with Meloidogyne arenaria in preemergence damping-off and pod rot of peanut were investigated by exposing seedlings or pods to defined inoculum densities of the various fungi or the nematode.
Abstract: Interactions of Pythium myriotylum with several fungi
and with Meloidogyne arenaria in preemergence damping-off
and pod rot of peanut were investigated by exposing seedlings
or pods to defined inoculum densities of the various fungi or
the nematode. Autoclaved soil was directly infested with
spores or resting structures of the fungi, or was artificially
infested with the fungi, assayed for the populations of fungi,
and diluted to contain desired levels of each fungus.
Nematodes were added directly as eggs in all experiments.
TL;DR: The decay of underground tissues of bean plants that had been inoculated with R. solani was induced by the removal of their shoot, but the remains of lesions from which no Rhizoctonia was isolated on agar plates, and the decomposed tissues of fibrous appearance, retained infectivity to bean hypocotyls.
Abstract: The decay of underground tissues of bean plants that had been inoculated with R. solani was induced by the removal of their shoot. R. solani and other fungi were isolated from lesions in the decying hypocotyls. The frequency of R. solani isolated from lesions decreased rapidly with increased decay of tissues, while that of other fungi increased. However, the remains of lesions from which no Rhizoctonia was isolated on agar plates, and the decomposed tissues of fibrous appearance from which the remains of lesions were removed, retained infectivity to bean hypocotyls. Histological studies of infected hypocotyls of shoot-removed plants showed the reactivation of inoculant fungus in lesions. When the inoculated plants become moribund, the pathogen grew from lesions into uninfected cortical tissues and penetrated vascular bundles directly or through endodermis. And monilioid cells of the fungus filled the thick walled vascular cells. The infected cortical layer decomposed in the early stage of decay, but the lesions consisting of sclerotia-like masses of hyphae were not decomposed. The decay of pith and vascular bundles proceeded slowly. They remained in the soil as fibrous plant residues containing monilioid cells of R. solani. The fungus in such remains of lesions and vascular cells persistes in soil at least until the next spring.
TL;DR: Aversion was observed between isolates ofRhizoctonia solani on inoculation in a culture plate and a digrammatic scheme is presented indicating the factors controlling this relationship.
Abstract: Aversion was observed between isolates ofRhizoctonia solani on inoculation in a culture plate. This phenomenon helped to study the relationship among fifty different isolates. Thirty three of the isolates showed aversion against some isolates and non-aversion against others. Seventeen of them, however, showed aversion against all the isolates. A digrammatic scheme is presented indicating the factors controlling this relationship.