Showing papers on "Rhizoctonia solani published in 1977"

Population of Rhizoctonia solani in Agricultural Soils Determined by a Screening Procedure

Abstract: WEINHOLD, A. R. 1977. Population of Rhizoctonia solani in agricultural soils determined by a screening procedure. Phytopathology 67:566-569. A rapid, reliable procedure for the quantitative assayed. Most of the fields, when sampled, were planted to determination of the population of Rhizoctonia solani in either cotton or potatoes. The population of R. solani ranged agricultural soils is presented. The procedure is based on wetfrom 0 to 15 propagules/ 100 g of soil and was distributed as screening soil through a 0.35-mm mesh sieve to remove the follows: 22, 24, 6, and 8 fields had populations within the organic particles that contain the pathogen. The material ranges of 0 to 0.5, 0.6 to 2.0, 2.1 to 5.0, and greater than 5.0 retained on the sieve is dispersed in 1% water agar and, after propagules/ 100 g, respectively. Therefore 77% of the soils 18 to 24 hr, incubation, suspected R. solanicolonies are sampled contained less than 2.0 propagules of R. solanil 100 transferred to potato-dextrose agar for identification. Soil g of soil. from 60 fields in the San Joaquin Valley of California were Rhizoctonia solani Kuihn has been extensively rubbing) into a beaker of water. The particles are evenly investigated for many years, and yet significant progress distributed on filter papers by filtering with a Bfichner in understanding its behavior in natural soil has been filter apparatus. Usually, six to eight papers are used for made only recently. In 1959, Boosalis and Scharen (1) 9-cm diameter plates, or three to four papers for 15-cm direported that R. solani was associated with particles of ameter plates. Cooled (52 C) liquid water agar (1.0%) is organic matter in soil, an observation confirmed by dispensed into plates to give a layer about 2.5 mm deep, others (2, 6, 10). Also in 1959, Papavizas and Davey (7) and then immediately the filter paper is inverted in the reported that R. solani colonized plant stem pieces when agar and agitated to dislodge and disperse the particles. they were incorporated into soil, and that the pathogen The plates are incubated for 18 to 24 hr, and suspect was readily recovered from the colonized tissue. colonies transferred to PDA for identification. An Rhizoctonia solani has been isolated from soil and the important factor in the success of this procedure is the relative inoculum density determined by organic particle rapid growth rate of R. solani. Suspect colonies are recovery (1, 10), stem segment colonization (2, 7, 8, 10), therefore selected on the basis of size and characteristic immersion tubes (2, 5, 10), disk-plates (3), and bioassays growth pattern. The colonies are best observed by holding with susceptible plants (2, 10). Recently, Ko and Hora (4) the plates above a black background in front of a published a procedure for quantitatively assaying soil for fluorescent light. By screening known amounts of soil, it R. solani and presented some information on populations is possible to determine the number of propagules in natural soil. quantitatively. Detailed studies on the ecology of soilborne plant A selective medium, described by Ko and Hora (4), pathogens are greatly facilitated by the quantitative may be used in place of water agar. For the soils we have determination of naturally-occurring populations. This assayed, however, water agar appears to be satisfactory report presents a procedure for the quantitative assay of and is easy to prepare. If necessary, bacterial growth can R. solani in field soil, and information on the population be checked by acidifying the medium with lactic acid. of this pathogen in the San Joaquin Valley of California. Two approaches were used to evaluate the reliability of the procedure. The first involved screening 500 to 3,000 g MATERIALS AND METHODS of soil, previously determined to have a high population of R. solani, through the 0.35-mm screen. All the soil that Description of the assay procedure and evaluation of passed through the screen was collected and dried. The reliability.-To do an assay, the soil sample is mixed portion that passed through the screen, and that retained, thoroughly, a subsample is removed for moisture each were brought to the original weight with soil that did determination, and three 50-g portions are processed not contain R. solani. These reconstituted soils were separately. Each portion is wet-screened through a 0.35assayed for R. solani by a slightly modified version of the mm mesh sieve (U.S. Standard Sieve Series, Sieve No. plant stem colonization technique of Papavizas and 45). The material retained on the sieve is washed (without Davey (7), and by growing cotton seedlings in them. The stem colonization procedure involved incorporation of 3 g of mature cotton stem segments 5 mm Copyright © 1977 The American Phytopathological Society, 3340 long and 3-5 mm in diameter into 500 g of soil. Clay pots Pilot Knob Road, St. Paul, MN 55121. All rights reserved. 15 cm in diameter were filled to within 6 cm of the top with

The nature and role of metabolic leakage from root-knot nematode galls and infection by Rhizoctonia solani.

Abstract: A severe root rot of tomato caused by Meloidogyne incognita and Rhizoctonia solani was associated with nutrient mobilization into gall tissue and root exudation. Root decay did not develop when root exudates were continuously removed by leaching. When leachates were collected from M. incognita-infected and control roots and applied to roots of tomatoes inoculated with R. solani alone, roots receiving leachates from M. incognita-infected roots developed a severe rot while roots receiving leachates from control roots were free of decay. During the fourth and fifth weeks following nematode infection, an increased mobilization of¹[sup4]C labelled compounds to nematode-infected roots occurred. Higher counts of water soluble nonvolatile¹[sup4]C labelled exudates leaked from nematode-infected roots than from control roots at each weekly sampling period. Higher concentrations of Ca, Mg, Na, K, Fe, and Cu were found in exudates from nematode-infected roots than from the control roots. During the first 14 days following nematode infection, carbohydrates were the major organic constituents in exudates leaking from nematode-infected roots. Fourteen days after nematode infection, nitrogenous compounds become the major organic constituents leaking from roots. Shifts in C/N ratio of root exudates from nematode-infected roots were associated with parasitic development of R. solani in tomato roots. Key Words: fungus-nematode interactions, Meloidogyne incognita, root exudates, C/N ratios.

Pesticide - Plant Disease Interactions: Effect of Cycloate on Sugar Beet Damping-Off Induced by Rhizoctonia Solani

Abstract: ALTMAN, J., and C. L. CAMPBELL. 1977. Pesticide plant disease interactions: effect of cycloate on sugar beet damping-off induced by Rhizoctonia solani. Phytopathology 67:1163-1165. Seedling survival of sugar beet cultivars MSH 212, FC 901, statistically significant (P = 0.05). Increased sugar beet and FC 702/5 was significantly reduced (P = 0.05) in soil seedling hypocotyl exudates in the presence of cycloate may infested with Rhizoctonia solani and amended with cycloate be implicated in the increased damping-off with cycloate (S-ethyl N-ethylthiocyclohexanecarbamate) at 4, 8, or 16 added at 4, 8, or 16 Mg/g soil, whereas reduction in fungal Ag/g soil, compared to infested, nonamended controls. The growth rate and/or colonization ability caused by the survival patterns for cultivars FC 701/5 and Mono Hy Al herbicide at 32 ltglg soil balanced with increased exudates, is were similar to those for MSH 212, FC 901, and FC 702/5, offered to explain why damping-off rates in infested soil were although differences for FC 701/ 5 and Mono Hy Al were not not increased by cycloate at /Ag/g soil. Additional key words: herbicide predisposition, Beta vulgaris. The increasingly important role of herbicides in trifluralin or dinoseb was applied to soil. They concluded modern agriculture necessitates the evaluation not only of that disease increase was due to a herbicide-induced the phytotoxic potential of a given herbicide but also of its reduction of snapbean structural and biochemical potential to alter the relationship between a suscept and defenses. Altman and Ross (2) reported increased its pathogens. Predisposition to disease by a herbicide seedling damping-off in sugar beets (Beta vulgaris L.) may be a direct effect on the physical structure or caused by R. solani in the field and in steamed and raw biochemical defenses of the suscept (12), an alteration of soil treated with prebulate and pyrazon in greenhouse the microclimate owing to the removal of weeds (6, 7), tests. They suggested that predisposition of the seedling to decrease in the \"antiphytopathogenic potential\" of a soil disease by the herbicides may in part explain why the use (11), or a direct stimulation of the pathogen (7, 10). None of some herbicides results in poorer stands of plants in of these factors operates independently. Thus, when each certain treated sugar beet fields compared with stands in is examined independently the results must be integrated nontreated fields. Altman (1) also found similar effects in to provide explanations for an interaction, another series of experiments with pyramin and cycloate. Heitefuss (5, 6) reported that herbicides could induce He found that glucose exudates from hypocotyls of sugar morphological and physiological changes in host plants, beets were greater at the soil-plant interface in the including reduction of wax formation on leaves, and herbicide-treated soil and concluded that the increase in changes in carbohydrate, nitrogen, and glucoside glucose exudates and an increase in mineral-containing metabolism. He also stated that plant growth may be hypocotyl exudates predisposed seedling to damping-off retarded or stimulated in the presence of a herbicide. Paul incided by R. solani. (8) and Paul and Schdnbeck (9) found significant The purpose of this work was to further investigate the reduction of root infection caused by Fusarium effect of cycloate, a thiocarbamate herbicide, on sugar moniliforme with the addition of 7 to 15 /.tg/ ml diallate (a beet seedling damping-off incited by R. solani. thiocarbamate herbicide) in both soil and liquid culture, compared to nontreated controls. Disease reduction was attributed chiefly to an effect on the host plant in which MATERIALS AND METHODS lignin-containing substances and 83-glucosidase activity were increased after application of diallate. Sugar beet cultivars used included FC 701/5 and FC Romig and Sasser (12) have shown that disease due to 702/5, Rhizoctonia-resistant breeding lines obtained Rhizoctonia solani Kfihn increased in snapbean when from the USDA-ARS, Fort Collins, Colorado; MSH 212, a moderately resistant hybrid and Mono Hy Al, a Copyright © 1977 The American Phytopathological Society, 3340 Rhizoctonia-susceptible commercial cultivar, both Pilot Knob Road, St. Paul, MN 55121. All rights reserved, obtained from Great Western Sugar Company; and FC

Population and distribution of sclerotia of Rhizoctonia solani kühn in sugar beet field soil

Abstract: The population and distribution of sclerotia of Rhizoctonia solani Kuhn in two sugar beet field soils was determined at harvest by a sieving-flotation method. In rhizosphere soil (RS) and non-rhizosphere soil (NRS) from the most heavily infected roots of sugar beets, 1.43–2.5 and 0.83–1.0 sclerotia g −1 dry soil were detected, respectively. In the soil around healthy sugar beet, these values were 0.04–0.12 and 0.03–0.04 sclerotia g −1 dry soil. More sclerotia were always obtained from RS than from NRS. More than 80% of the sclerotia were in the upper 10 cm of soil and within 10 cm of diseased roots. Therefore, there is a non-uniform distribution of sclerotia of R. solani in soil. The sclerotial population in soil increased significantly with disease severity and a good correlation was obtained between the number of sclerotia and the disease severity on infected plants. Most of the sclerotia collected from the field soil ranged in size from 0.5 to 2.0 mm diameter. Viability of sclerotia increased as severity of crown rot increased and as the size of the sclerotia increased. Conversely, there was a progressive decrease in sclerotial germination with increasing depth in soil and increasing distance from the infected root.

Pesticide - Plant Disease Interactions: Effect of Cycloate on Growth of Rhizoctonia solani

Abstract: CAMPBELL, C. L., and J. ALTMAN. 1977. Pesticide -plant disease interactions: effect of cycloate on growth of Rhizoctonia solani. Phytopathology 67: 557-560. Linear growth of Rhizoctonia solani after 72 hr at 20 C was in steamed soil amended with 4 Mg!g cycloate, colonization significantly less on all nutrient concentrations of potato- of 5-mm-long mature bean hypocotyl segments by R. solani dextrose agar amended with cycloate (S-ethyl N-ethylthio- was slightly greater than in soil without cycloate. At 16 and 32 cyclohexanecarbamate) from 10 to 100 /ig/ml, than in Ag/g cycloate, colonization of hypocotyl segments was controls without cycloate. Rate of growth of mycelium of R. significantly less than in nonamended controls in both solani was less in Czapek-Dox broth with 1 g yeast steamed and raw soil. Colonization of sterile sugar beet seeds extract/liter amended with 4 or 8 btg/ml cycloate, than in by R. solani also was less with 8, 16, and 32 jg/g cycloate controls. In raw soil amended with 4 and 8 Mg! g cycloate, and than in controls. Herbicides are becoming more important in modern growth of the fungus in pure culture in the presence of agriculture. Although much research is done to evaluate Dacthal. the phytotoxicity of herbicides to economic crop plants, Altman (1) and Altman and Ross (2) observed both in questions remain concerning the effects of herbicides on field and greenhouse work that an interaction, leading to soil microorganisms including soil-borne plant increased disease incidence, existed between sugar beet pathogens. (Beta vulgaris L.) seedling damping-off caused by R. Rodriguez-Kabana et al. (11) using rates ranging from solani and certain herbicides used in sugar beet culture those "considered likely to accumulate in soil under field which included cycloate, pebulate, and pyrazon. The applications to others much higher than would be authors concluded that this interaction could in part expected," found that in liquid culture, diuron had little explain poorer stands of plants in certain herbicideeffect on the mycelial production of Rhizoctonia solani treated fields compared with stands in nontreated fields. Kfihn. EPTC generally had little effect on the growth of The purpose of this work was to investigate the effect of R. solani, although the fungus initially was inhibited by cycloate (S-ethyl N-ethylthiocyclohexanecarbamate) this herbicide. Atrazine inhibited mycelial production on R. solani. This herbicide currently is recommended for throughout the 22-day trial period, but paraquat use as a preplant treatment for sugar beets in Colorado increasingly inhibited the fungus as herbicide and in all other intermountain states in which sugar beets concentration increased, are grown. Ebner (5) found that R. solaniwas sensitive to diuron at 125 #g/ml and to linuron at 60 and 125 Ag/ml. In media MATERIALS AND METHODS

Effects of the herbicides fluometuron and prometryn of Rhizoctonia solani in soil cultures

Abstract: Responses of Rhizoctonia solani to herbicides in soil cultures were assessed by measuring soil enzyme activity and other growth-related factors. Both beta-galactosidase (EC 3.2.1.23) and phosphatase (EC 3.1.3.1.3.1.3.2) activities were highly correlated with amounts of mycelium in soil. Both enzyme activities were reduced significantly by either fluometuron or prometryn at 40 microgram/g of soil; the pathogen was more distinctly suppressed by fluometron and showed a stronger tendency to overcome the effects of prometryn with time. Inhibition was also reflected in reduced ultilization of glucose and less CO2-C evolved. Except for an increase in beta-galactosidase activity in the presence of 1 microgram fluometuron, low levels of either herbicide had little effect on the pathogen.

Pesticide-Plant Disease Interactions: the Influence of Aldicarb On Growth of Rhizoctonia solani and Damping-Off of Sugar Beet Seedlings

Abstract: TISSERAT, N., J. ALTMAN, and C. L. CAMPBELL. 1977. Pesticide-plant disease interactions: the influence of aldicarb on growth of Rhizoctonia solani and damping-off of sugar beet seedlings. Phytopathology 67: 791-793. Addition of aldicarb [2-methyl-2-(methylthio) propion- and amended with aldicarb at 16 #tg/g. In steamed soil aldehyde, O-(methylcarbamoyl) oxime] to soil infested with inoculated with R. solani inoculum at 200 Ag/g, colonization Rhizoctonia solani significantly increased damping-off of of mature bean hypocotyl segments after 72 hr was increased sugar beet seedlings in greenhouse and growth chamber with aldicarb at 8 Ag/g, but not with 32 Mg/g. Linear growth studies. Seedling survival was lowest in steamed soil of R. solani was reduced on potato-dextrose agar amended inoculated with R. solani barley grain inoculum at 400 Mg! g with aldicarb at 4, 8, 16, and 32 Mg! ml.

3-(3,4-Epoxy-4-methylcyclohexyl)butyl esters

Abstract: 3-(3,4-Epoxy-4-methylcyclohexyl)butyl esters form a new class of compounds exhibiting fungicidal activity and plant growth regulant activity. In fungicide tests, the compounds of this invention prove effective against Fusarium oxysporium, Pythium debaryanum, Rhizoctonia solani and Sclerotium rolfsii. In herbicide tests, post-emergent application of the compounds of this invention provides plant growth regulant action, such as cotton defoliation and plant growth retardation activity.

Substituted 3‐furamides with specific activity against basidiomycetes

Abstract: Substituted furanilides and furamides show very good activity against Basidiomycetes. Whilst N-cyclohexyl-x-methyl-3-furamides (where x- is one or more of the vacant positions in the furan ring) further substituted on the amide nitrogen have specific activity against Basidiomycetes (e.g. Ustilago nuda, U. scitaminea, Tilletia tritici and Rhizoctonia solani), N-cyclohexyl-N-methoxy-2,5-dimethyl-3-furamide also gives good control of other classes of fungi (e.g. Fusarium nivale and Helminthosporium gramineum). This compound is to be developed under the Code Number BAS 389 F as a mercury-free seed dressing alone or in combination with other fungicides.

Fungicidal Constituents in “Kuntan” (Calcined Rice Chaff) Smoke

Abstract: Fungicidal constituents against Rhizoctonia solani and Alternalia mali were isolated from Kuntan (calcined rice chaff) smoke. The fungicidal constituents were phenolics (o, m and p-cresol, 4-ethylphenol, 2, 3, 6-trimethylphenol, 4-n-propylphenol, 4-ethyl-2-methoxyphenol, 4-n-propyl-2-methoxyphenol and 4-allyl-2-methoxyphenol) and α, β-unsaturated-γ-butyro-lactones (2-methyl-4-hydroxy-2-hexenoic acid lactone and 2-ethyl-4-hydroxy-2-pentenoic acid lactone). The anti-pathogenic nature of Kuntan may be due in part to the fungicidal constituents isolated from Kuntan smoke.

Damping-off in cotton controlled with combination seed treatment fungicides

Abstract: Not Available – First paragraph follows: Damping-off of cotton seedlings in southern California is caused by two fungi, Rhizoctonia solani and Pythium spp. Seed rot and seedling decline are particularly severe during cool, wet weather and when soil temperatures are below 60° F. Several new fungicides were tested against common, standard, commercial fungicides.

On the oxidation of dihydroxyphenylalanine and benzidine in crude cell-free fungal extracts.

Abstract: 2. Ridgway, R. 1912. Color standards and color nomenclature. Publ. by the author, Washington, D.C. 53 pl., 43 p. 3. Talbot, P. H. B. 1965. Studies of "Pellicularia" and associated genera of Hymenomycetes. Persoonia 3: 371-406. 4. . 1970. Taxonomy and nomenclature of the perfect state. Pp. 20-31. In J. R. Parmeter, Jr., Ed., Rhizoctonia solani, biology and pathology. University of California Press, Berkeley, Los Angeles, and London. 5. Tu, C. C. 1974. Culture, development, and sexual states of Rhizoctonia, Sclerotium, and some related fungi. Ph.D. Thesis, Univ. of Florida, Gainesville, 199 p. 6. , and J. W. Kimbrough. 1975. Morphology, development, and cytochemistry of the hyphae and sclerotia of species in the Rhizoctonia complex. Canad. J. Bot. 53: 2282-2296.

Occurrence of soil fungi in a potato plantation

Abstract: The forecrops applied in potato cultivation affected the occurrence of Rhizoctonia solani Kuhn and other soil fungi. The most common species found appeared to be: Penicillium nigricans Thom, P. jenseni Zaleski, P. vinaceum Gilman et Abbott. and P. raciborskii Zaleski.

Mutations of Fusarium oxysporum and Rhizoctonia solani by TCMTB

Abstract: Upon screening several fungicides, a few Fusarium oxysporum isolates and one Rhizoctonia solani isolate showed a distinct and sudden decrease in sensitivity to TCMTB (2-(thiocyanomethylthio)-benzothiazole). The screening was carried out in Petri dishes using an agar medium, mixed with the test fungicides, in the center of which a mycelial piece of the test fungus was placed. In several TCMTB-containing plates, a sectorial differentiation of mycelial growth was observed. This localized decrease in sensitivity was clearly different from the decrease in sensitivity as seen upon serial subculturing of a fungus on fungicide-containing medium. When the fungal strains isolated from the sectors of less inhibited growth were tested in new experiments, the decreased sensitivity seemed to be stable. In these strains, sectorial differentiation was more frequent than in the original isolates. The same phenomenon, but to a more limited extent, was also found with dichlozoline (3x), benomyl (1x) and thiophanate (1x).

Interrelationships between Heterodera rostochiensis and soil fungi on tomato

Abstract: Rhizoctonia solani Kuhn [= Corticium solani (Prill. et Del.) Bourd. et Ganz.] and Colletotrichum coccodes (Wallr.) Hughes [= C. atramentarium (Berk. et Br.) Taubenh.] were considered to be contributing factors of 'potato sickness' in the United Kingdom (Cheal, 1929; Edwards, 1929; Triffitt, 1931). Miles (1930) while considering R. solani to be a contributory factor disregarded C. cocco des to have any role. However, Millard et al. (1932) did not support this view. Dunn and Hughes (1964) did not find any synergistic effect between the potato cyst eelworm (Heterodera rostochiensis Woll.) (PCE) and C. coccodes. Greater reduction in the growth of potato and tomato in the presence of both R. solani and PCE than PCE alone was observed by Grainger and Clark (1963) and Dunn and Hughes (1964), respectively.

イネ褐色紋枯病(新称)について

Abstract: A new type of sheath blight of rice was first discovered in Yamaguchi Prefecture in 1959. The symptom of the rice sheath infected by pathogen was similar to that of rice sheath blight, but, it had more darkish brown or black color than rice sheath blight (caused by the cultural type IA of Rhizoctonia solani Kuhn). In addition, the sclerotia were not observed outside the infected sheath. This disease was caused by the cultural type III B of Rhizoctonia solani Kuhn. And this fungus was identified with both of the pathogens of rice sheath that were reported by Nonaka, in 1964 and Taketani & Tamura, in 1970. On the basis of differences in anastomosis groupe, cultural type, symptom, pathogenicity, and effect of organo-arsenic compound from the sheath blight of rice, brown sheath blight of rice was proposed as the disease name.