Showing papers on "Rhizoctonia solani published in 1991"

Transgenic Plants with Enhanced Resistance to the Fungal Pathogen Rhizoctonia solani

Abstract: The production of enzymes capable of degrading the cell walls of invading phytopathogenic fungi is an important component of the defense response of plants. The timing of this natural host defense mechanism was modified to produce fungal-resistant plants. Transgenic tobacco seedlings constitutively expressing a bean chitinase gene under control of the cauliflower mosaic virus 35S promoter showed an increased ability to survive in soil infested with the fungal pathogen Rhizoctonia solani and delayed development of disease symptoms.

Induction of systemic resistance of cucumber to Colletotrichum orbiculare by select strains of plant growth-promoting rhizobacteria

Abstract: Ninety-four strains of plant growth-promoting rhizobacteria (PGPR) were screened for induction of systemic resistance using a model system of cucumber and anthracnose, caused by Colletotrichum orbiculare. Compared with a nonbacterized, challenged control, treatment of cucumber seeds with six PGPR strains resulted in a significant reduction in lesion size after challenge-inoculation with C. orbiculare. Four of the six PGPR strains that induced resistance in cucumber produced HCN in vitro. Antagonism in vitro toward Pythium ultimum, Rhizoctonia solani, and C. orbiculare on three media generally was absent with five PGPR strains and weak with one strain. Rifampicin-resistant mutants of the PGPR strains colonized roots at mean population densities of log 6.5 to 8.3 cfu g(-1) of root at 7 days after planting and log 4.1 to 6.1 cfu g(-1) at 21 days after planting. None of the strains was recovered from surface-disinfested petioles on the day of challenge with C. orbiculare. Roots from plants bacterized with PGPR strains showed less necrosis than the nonbacterized, challenged control. The results support the conclusion that some PGPR strains applied to seed can induce systemic resistance to C. orbiculare

Factors relating to peanut yield increases after seed treatment with Bacillus subtilis

Abstract: Bacillus subtilis, when added as a seed treatment, consistently colonized the roots of peanut plants at rates exceeding 10 4 colony-forming units (cfu) per gram of root tissue when evaluated 120 days after planting. Yield increases from 1982 to 1985 ranged from −3.5 to 37%, with only two incidences of negative responses in 24 tests. Peanuts responded most favorably to the bacterial seed treatment when subjected to stresses, such as limited water availability, poor rotational practices, or cool soils, caused by early plantings. Treatment of peanut seed with B. subtilis was associated with improved germination and emergence, increased nodulation by Rhizobium spp., enhanced plant nutrition, reduced levels of root cankers caused by Rhizoctonia solani AG-4, and increased root growth. The means by which B. subtilis may affect yield in peanuts are multiple and are not operative at the same time, making predictions of degree of yield responsiveness difficult

Evidence that chitinase produced by Aeromonas caviae is involved in the biological control of soil-borne plant pathogens by this bacterium.

Abstract: A chitinolytic isolate of Aeromonas caviae was isolated from roots of healthy bean plants grown in soil artificially infested with Sclerotium rolfsii. Under greenhouse conditions, the bacterium controlled Rhizoctonia solani and Fusarium oxysporum f.sp. vasinfectum in cotton (78 and 57% disease reduction, respectively) and S. rolfsii in beans (60% disease reduction). Seed coating was the most effective application method for controlling R. solani in cotton. There was no evidence of inhibition of the fungal pathogens by A. caviae. A caviae partially lysed live mycelium of R. solani, S. rolfsii and F. oxysporum f.sp. vasinfectum when their mycelium served as a sole carbon source in liquid medium. A high chitinolytic activity was found when colloidal chitin was used as a sole carbon source, with an optimum pH between 6.0–7.0. No β-3-glucanase was produced by the bacterium. After partial purification of the enzyme by affinity adsorption to colloidal chitin, three bands appear in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). One strong band with a molecular weight of ca. 80 kDa, and two weak bands with molecular weights of 48 and 59 kDa. Using the chromogenic substrate pNp-chitobiose, the partially purified chitinase from A. caviae was shown to act in an exo-splitting manner.

Wheat yield depression associated with conservation tillage caused by root pathogens in the soil not phytotoxins from the straw

Abstract: Wheat planted directly into soil mulched with straw of a previous wheat crop (mulch or conservation tillage) typically grows and yields poorly relative to that planted into a prepared seedbed with straw residue burned or buried (clean tillage). This injurious effect associated with straw mulches has been greatest in the higher-rainfall wheat-growing areas, or in wet years in normally dry areas. Researchers have focused for the past 30 yr on putative phytotoxins thought to be liberated during microbial colonization or breakdown of the straw on or near the soil surface when wet. The results of experiments reported herein indicate that the causal microorganisms are in the soil and not the straw as would be required if phytotoxic straw decomposition products were important. The injury in these experiments resulted from at least three root diseases, all favored by the lack of crop rotation. The three root diseases were take-all caused by Gueumannomyces graminis var. trici, Rhizoctonia root rot caused mainly by Rhizoctonia solani AG8, and Pythium root rot caused by several Pythium spp. The effect of straw on, or mulched into, the soil surface possibly amounts to no more than helping to keep the top 10–15 cm of soil, the zone occupied by the root pathogens, more ideally moist for their activity. The results suggest that conservation tillage is feasible for wheat in the higher rainfall areas when used in combination with a break from wheat.

Phytoalexin response is elicited by a pathogen (rhizoctonia solani) but not by a mycorrhizal fungus (glomus mosseae) in soybean roots

Abstract: A container system was constructed to study the response of soybean roots to infection by mycorrhizal or pathogenic fungi. The system allows a rapid and synchronous inoculation byGlomus mosseae orRhizoctonia solani. The phytoalexin glyceollin was measured in roots of inoculated and uninoculated plants for a period of 30 days. A significantly increased content of phytoalexin was found inR. solani-infected roots as compared to uninfected control roots. However, there was no difference in the glyceollin contents of the mycorrhizal and the control roots for up to 23 days after inoculation. The accumulation of glyceollin inR. solani-infected roots was not influenced by a subsequent inoculation withG. mosseae. Moreover glyceollin accumulated in mycorrhizal plants to the same extent as in control plants when they were inoculated withR. solani. The two fungi did not mutually influence the course of infection when they were inoculated together.

Pseudomonas cepacia and Pseudomonas putida as winter wheat inoculants for biocontrol of Rhizoctonia solani

Abstract: Pseudomonas cepacia R55 and R85 and Pseudomonas putida R104, antagonistic towards plant pathogenic fungi in vitro, were assessed as seed inoculants for winter wheat (cv. Norstar) grown in a growth ...

Biological control of soil pests by mixed application of entomopathogenic and fungivorous nematodes.

Abstract: In greenhouse experiments, massive application of the fungivorous nematode, Aphelenchus avenae, in summer at 26-33 C (1 x l0⁵ nematodes/500 cm³ autoclaved soil) or in autumn at 18-23 C (5 x 10⁴ nematodes/500 cm³ autoclaved soil) suppressed pre-emergence damping-off of cucumber seedlings due to Rhizoctonia solani AG-4 by 67% or 87%, respectively. Application of 2 x l0⁵ A. avenae to sterilized soil infested with R. solani caused leafminer-like symptom on the cotyledons, which did not occur in mixed inoculations with the entomopathogenic nematode, Steinernema carpocapsae. When 1 x 10⁶ A. avenae were applied 3 days before inoculation with 100 Meloidogyne incognita juveniles, gall numbers on tomato roots were reduced to 50% of controls. Gall numbers also were suppressed by S. carpocapsae (str. All). Reduction in gall numbers was no greater with mixed application of A. avenae and S. carpocapsae than with application of single species, even though twice the number of nematodes were added in the former case. These nematodes were positively attracted to tomato root tips. Aphelenchus avenae suppressed infection of the turnip moth, Agrotis segetum, but not the common cutworm, Spodoptera litura, by S. carpocapsae.

Effects of fungal root pathogens on the population dynamics of biocontrol strains of fluorescent pseudomonads in the wheat rhizosphere.

Abstract: The influences of Gaeumannomyces graminis var. tritici (which causes take-all of wheat), Rhizoctonia solani AG-8 (which causes rhizoctonia root rot of wheat), Pythium irregulare, P. aristosporum, and P. ultimum var. sporangiiferum (which cause pythium root rot of wheat) on the population dynamics of Pseudomonas fluorescens 2-79 and Q72a-80 (bicontrol strains active against take-all and pythium root rot of wheat, respectively) in the wheat rhizosphere were examined. Root infection by either G. graminis var. tritici or R. solani resulted in populations of both bacterial strains that were equal to or significantly larger than their respective populations maintained on roots in the absence of these pathogens. In contrast, the population of strain 2-79 was significantly smaller on roots in the presence of any of the three Pythium species than on noninfected roots and was often below the limits of detection (50 CFU/cm of root) on Pythium-infected roots after 40 days of plant growth. In the presence of either P. aristosporum or P. ultimum var. sporangiiferum, the decline in the population of Q72a-80 was similar to that observed on noninfected roots; however, the population of this strain declined more rapidly on roots infected by P. irregulare than on noninfected roots. Application of metalaxyl (which is selectively inhibitory to Pythium spp.) to soil naturally infestated with Pythium spp. resulted in significantly larger rhizosphere populations of the introduced bacteria over time than on plants grown in the same soil without metalaxyl. It is apparent that root infections by fungal pathogens may either enhance or depress the population of fluorescent pseudomonads introduced for their control, with different strains of pseudomonads reacting differentially to different genera and species of the root pathogens.

Activity of four plant leaf extracts against three fungal pathogens of rice.

Abstract: Leaf extracts of four plant species, Piper betle, Ocimum sanctum, Nyctanthes arbor-tristis and Cirtus limon were effective in reducing the radial in vitro growth of Pyricularia oryzae, Cochlibolus miyabeanus and Rhizoctonia solani P. betle was found to be the best, followed by O. sanctum, in reducing the growth of the pathogens completely in vitro and in checking the spread of blast, brown spot and sheath blight diseases of rice in vivo

Protection of potato from Rhizoctonia canker with binucleate Rhizoctonia fungi.

Abstract: Fifteen isolates of binucleate Rhizoctonia fungi (BNR) were studied as potential biocontrol agents for protection of potato from Rhizoctonia canker in artificially infested greenhouse soil and potato fields naturally infested with Rhizoctonia solani (AG-3). Eight of the BNR reduced incidence and severity of Rhizoctonia stem canker in greenhouse experiments by an average of 78 and 85%, respectively. In a field naturally infested with R. solani, selected isolates of BNR and the fungicide Tops 2.5D (thiophanate-methyl) were equally protective of potato from Rhizoctonia stem canker. BNR isolates gave protection of potato from Rhizoctonia stolon canker similar to PCNB and superior to Tops 2.5D. Cultivars Atlantic, Irish Cobbler, Kennebec, Norchip, Russet Burbank, and Superior were protected equally from Rhizoctonia stem canker by selected isolates of BNR under field conditions. Isolates of BNR show potential as biocontrol agents for protection of potato from Rhizoctonia canker.

Sensitivity of Rhizoctonia species to different fungicides

Abstract: Of 14 fungicides with different modes of action, cyproconazole and tolclofos-methyl were generally inhibitory both in vitro and in vivo against all tested isolates of five Rhizoctonia species belonging to the teleomorphs Thanatephorus cucumeris, Waitea circinata or Ceratobasidium cereale. Triadimenol and carboxin provided considerable variation in activity against different species and isolates, whereas prochloraz was ineffective against all isolates. Imazalil and fenarimol showed moderate control, whereas flusilazole, propiconazole, fenpropimorph and benomyl showed strong activity against R. zeae and R. oryzae, but were much less effective against R. sasakii, R. cerealis and R. solani. Benodanil and iprodione controlled all isolates of R. cerealis and R. solani, but were not very effective against R. zeae and R. oryzae. Pencycuron showed strong activity against R. sasakii and most R. solani isolates, moderate activity against R. zeae, and was ineffective against R. oryzae and R. cerealis.

Isolates of Rhizoctonia solani anastomosis group 2-2 pathogenic to soybean

Abstract: Two highly virulent isolates of Rhizoctonia solani, 61D-3 and 65L-2 (ATCC 66489), from diseased soybean (Glycine max) plants grown in Illinois were identified as members of anastomosis group (AG) 2-2. They caused crown and root rot on inoculated plant species in the Chenopodiaceae, Fabaceae, and Poaceae at an inoculum level of 100 μg of fresh mycelium per gram of soil in the greenhouse. Both isolates produced few loose, thick-walled sclerotia and maintained their pathogenicity to soybean after 2 yr in storage (...)

Effects of rotation length, fungicide treatment of seed tubers and nematicide on diseases and the quality of potato tubers

Abstract: Summary In 1982 – 88, potatoes were grown in 2-, 4- and 6-course rotations with spring barley on a field infested with Globodera rostochiensis Severity of stem canker and black scurf increased with increasing frequency of previous potato crops, and seed tuber treatment with tolclofos-methyl became less effective in controlling diseases This suggested that previous crops had increased the amounts of soil-borne inoculum of Rhizoctonia solani Oxamyl soil treatment increased stem canker in one year and decreased black scurf in four years Seed tuber treatment with imazalil or prochloraz decreased stem base infection by Polyscytalum pustulans and skin spot and silver scurf on tubers Black dot was prevalent on tubers in all years and was not affected by seed tuber treatment or previous cropping Oxamyl increased black dot and common scab in five years and decreased % tuber dry matter in six years Cysts of G rostochiensis were found attached to Desiree but not to Maris Piper tubers in August At harvest tubers of both cultivars were affected by superficial pitting and its severity was related to soil populations of G rostochiensis at planting This damage was controlled by oxamyl It is suggested that the pitting developed from holes made in the tuber skin at larval invasion In 1989, Desiree seed tubers and healthy mini tubers were planted in all plots and severity of stem canker and black scurf increased with increasing proximity of previous potato crops and with the number of previous crops Black dot on stems and tubers was not affected by previous cropping but was much less severe in a plot that had not grown potatoes during the seven years of the experiment The severity of common scab generally decreased as the number of preceding potato crops increased

Development of In Vivo Assays for Prescreening Antagonists of Rhizoctonia solani on Cotton.

Abstract: Prescreens of bacteria for biological control of soilborne diseases traditionally consist of tests for antibiosis in vitro. Two in vivo assays were developed as possible alternative prescreens for selecting candidate biological control agents for preemergence and postemergence damping-off diseases of cotton caused by Rhizoctonia solani. In the «radicle assay,» radicles from surface-disinfested seed were inoculated with R. solani. In the «hypocotyl assay,» excised surface-disinfested hypocotyls were inoculated with the pathogen (...)

Control of Rhizoctonia solani in potato by biological, chemical and integrated measures

Abstract: The effects of biological, chemical and integrated control on the formation of selerotia ofRhizoctonia solani on new potato tubers were studied in experimental fields. Sprouts of seed tubers, sprouted in daylight, were inoculated withVerticillium biguttatum, an ecologically obligate mycoparasite ofR. solani. Fungicides were mixed with the top soil. Biological control byV. biguttatum increased the percentage of harvests with less than 5% loss due to grading from 24% (non-inoculated) to 56%. Fungicides at the recommended rates usually gave good results but lower doses were less effective in sand than in loam soils. When fungicides were combined with biological control, the results were often, better: harvests with less than 5% sorting loss increased from 56 to 81%. Integrated control with pencycuron at 25% of the recommended rate was about equal to chemical control with pencycuron at full rate. The advantages of integrated control are discussed.

Activity of tebuconazole on Sclerotium rolfsii and Rhizoctonia solani, two soilborne pathogens of peanut

Abstract: Tebuconazole, an ergosterol biosynthesis inhibitor, has a high level of activity against Sclerotium rolfsii and Rhizoctonia solani in vitro. Mean ED 50 values for inhibition of mycelial growth of two isolates each of R, solani anastomosis group 4 (AG-4) and S. rolfsii were 0.17 and 0.08 μg/ml, respectively, for tebuconazole, compared with 24.3 and 3.9 μg/ml, respectively, for the pentachloronitrobenzene (PCNB) standard. The ED 50 values for the inhibition of sclerotia formation by S. rolfsii were 0.13 and 4.99 μg/ml for tebuconazole and PCNB (...)

Variability in the Sensitivity of Rhizoctonia solani Anastomosis Groups to Fungicides

Abstract: Tolclofos-methyl, iprodione and cyproconazole, among the eleven fungicides tested in vitro, gave consistently strong inhibition against all ten anastomosis groups (AGs) of Rhizoctonia solani. Carboxin, furmecyclox, thiabendazole, fenpropimorph and vinclozolin also inhibited all AGs but with wide variations in toxicity levels (EC90 values). Pencycuron showed strong activity against four AGs but was ineffective against the other six AGs. Generally, R. solani AGs were insensitive to fenarimol and imazalil. Tolclofos-methyl strongly inhibited 23 AG2-1 and 20 AG4 rapeseed/canola R. solani isolates from different locations in Saskatchewan, Alberta and Manitoba. The same isolates were also sensitive to iprodione, cyproconazole and carboxin. All AG4 canola isolates were insensitive to pencycuron (EC90 > 500 mg/l) while AG2-1 isolates showed highly variable levels of sensitivity with EC90s ranging from 0.5 to 220 mg/l. Tolclofos-methyl, applied to Brassica napus (canola) cv. Westar seed at 1 g a.i./kg, provided 75—100 % control of seedling damping-off in pots infested with AG2-1 or AG4 isolates. In parallel experiments, pencycuron (1 g a.i./kg seed) failed to control damping-off by AG4 canola isolates and gave variable disease control against AG2-1 isolates.

Assessment of genetic relatedness among double-stranded RNAs from isolated of Rhizoctonia solani from diverse geographic origins

Abstract: The degree of genetic relatedness among double-stranded RNA (dsRNA) components from 51 isolates of Rhizoctonia solani of diverse geographic origins was analyzed by RNA-RNA hybridization. The cultures included in this study were classified into five anastomosis groups (AGs 1−5), and originated from different geographic locations in the United States, Japan, and Israel. Radioisotope-labeled total dsRNA from eight Japanese cultures (AGs 1, 2, 4, and 5) did not hybridize to northern blots of total dsRNA from American cultures of the corresponding AGs. By contast, total dsRNA from a Japanese AG 3 isolate hybridized to dsRNA from two of the nine North American cultures tested (...)

Control of bottom rot disease of lettuce (Rhizoctonia solani) using preparations of Trichoderma viride, T. harzianum or tolclofos-methyl

Abstract: Isolates of Trichoderma were tested for their ability to control Rhizoctonia solani in lettuce seedlings and mature plants in a glasshouse. The best isolate (T. viride IMI 298375) was tested for its ability to control bottom rot disease in mature lettuce plants grown in polythene tunnels. Control was achieved in several trials but there was little evidence for much improvement after repeated applications and control with Trichoderma was poorer than that obtained with a standard treatment with tolclofos-methyl. Evidence was obtained to suggest however that enhanced growth of lettuce plants following treatment with Trichoderma can produce marketable yields of lettuce similar to those obtained with tolclofos-methyl.

A new formulation system for the application of biocontrol fungi to soil

Abstract: A new biocontrol formulation system was devised that does not require sterile conditions during preparation. It involves mixing vermiculite and powdered wheat bran with wet or dry fermentor biomass of Trichoderma spp. or Gliocladium virens, moistening with 0.05 N HCl, and drying the mixture. Before application to soil, the preparation (VBA‐FB) is activated by re‐moistening with 0.05 N HCl and incubated at room temperature for 2–3 days to stimulate development of young hyphae of the biocontrol fungus. Populations of biocontrol fungi proliferated to greater than 107 colony‐forming units (cfu) per g of soil when activated VBA‐FB was added to soil. In soil artificially infested with Rhizoctonia solani, seven isolates of the 14 studied added as VBA‐FB reduced survival and 12 reduced saprophytic growth of the pathogen. Of these, two isolates of T. hamatum (TRI‐4, Tm‐23) and one of T. harzianum (Th‐87) were the most effective. Preparations formulated with either wet or dry biomass effectively reduced pathogen su...

Effect of peat-bran inoculum ofTrichoderma species on biological control ofRhizoctonia solani in lettuce

Abstract: A range of known biocontrol or plant growth-stimulating species ofTrichoderma orGliocladium were grown on peat-bran substrate to yield between 5×107−3×1010 colony forming units (cfu's)g−1 substrate after 14 days growth. Inocula were incorporated into peat:sand potting compost infested withRhizoctonia solani to give 7–8 × 104 cfu's of antagonist g−1 compost and assessed for biological control activity using lettuce seedlings. Six of the eight antagonists decreased daming-off and three of these consistently increased yield in comparison withR. solani treatment alone.

Formulation of a soil amendment to control damping-off of slash pine seedlings.

Abstract: Seventeen chemical amendments were added (1%, w/w) individually to sandy soil artificially infested with Rhizoctonia solani (AG-4) or a binucleate species of Rhizoctonia (CAG-3). Alum, Al 2 (SO 4 ) 3 , CaCl 2 , Ca(NO 3 ) 2 , CaO, glycerine, K 2 HPO 4 , KCl, K 2 SO 4 , NH 4 NO 3 , (NH 4 ) 2 SO 4 , urea and triple superphosphate inhibited colonization of pine stem segments by R. solani and the binucleate Rhizoctonia to varied degrees. In 0.1% (w/v) water solution, these chemical inhibited sporulation of Pythium aphanidermatum (...)

Effect of soil compaction on growth, yield and root rots of white beans in clay loam and sandy loam soil.

Abstract: The effect of soil compaction on plant growth, yield and root rot severity of white beans was investigated in sandy loam (Harrow) and clay loam (Chatham) soils between 1983 and 1985. The root rots were mainly Rhizoctonia solani (Rs) and F. solani f. sp. phaseoli (Fs). The ratios of Rs to Fs in infected root pieces were 10:6 and 10:4 in Harrow and Chatham locations, respectively. There were significant reductions in root and shoot biomass and yield, and an increase in root rot severity as soil compaction increased. At the same degree of soil compaction, plants grew better and yielded more in clay loam than in sandy loam. The relationships between soil compaction and other soil environmental factors such as water, aeration and temperature are discussed.

Characteristics and pathogenicity of isolates of Rhizoctonia spp. associated with damping-off of sugar beet

Abstract: Rhizoctonia solani and R. cerealis were isolated from diseased sugar-beet seedlings in Ireland. Isolates of R. solani were assigned to anastomosis groups AG-2, AG-4, AG-5 and an unidentified group that did not anastomose with recognized tester isolates. Cultures of AG-2 were similar to those of AG-5 on oatmeal agar (OA) and potato-dextrose-marmite agar (PDMA). Cultures of AG-4, the unidentified group and R. cerealis were morphologically distinct from one another, AG-2 and AG-5. The optimum temperature for growth of AG-2 was 225 C, with optimum growth of AG-4, AG-5 and the unidentified group at 275-C. R. cerealis grew slower than all groups of R. solani, with optimum growth at 225°C. Hyphae of R. cerealis were significantly narrower than those of the groups of R. solani studied. In glasshouse pathogenicity tests, some AG-2 and all AG-4, AG-5 and isolates from the unidentified group caused damping-off of beet seedlings. In controlled environments of 10-25°C, an AG-2 isolate was the most aggressive at 10 C whilst AG-4, AG-5 and the unidentified group caused most disease at or above 15°C. R. cerealis was also pathogenic to beet seedlings, causing damping-off at 10 and 15 C.

Cultural practices in the control of bean root rot.

Abstract: Bean root rot (a complex of Apharwmyces spp., Fusarium solani f. sp. phaseoli, Pythium spp. and Rhizoctonia solani) affects winter-grown fresh beans at Gympie, Queensland. In 5 trials conducted in 1986-88, cultural practices (depth of planting, depth of cultivation, hilling) and a fungicide treatment were examined as methods of control of the disease. The experiments were sited on a clay-loam soil, and under these conditions, shallow planting (25 mm) was the most effective treatment, significantly (P<0.05) reducing the severity of root rot relative to the standard depth of 50 mm.

Fungitoxic effects of balansia cyperi

Abstract: Fungitoxic effects ofthe fungus Balansia cyperi infecting the sedge Cyperus rotundus were examined. Comparisons of fungal colonizers of B. cyperc'-infected and uninfected C. rotundus showed Rhizoctonia solani to inhabit leaves from uninfected plants but not leaves from B. cypm'-infected plants. In vitro bioassays with solvent extracts of B. cyperi mycelia and culture filtrates showed growth inhibition of test fungi, including Fusarium oxysporum and R. solani. Solvent extracts of leaves from B. cyperiinfected plants inhibited growth of most test fungi including F. oxysporum, R. oryzae, and R. solani. Extracts from uninfected plants inhibited the latter two species but to a lesser degree. Results suggest that B. cyperi infecting C. rotundus potentially may deter infection of its host by other more pathogenic

Evaluation of the leaf juice of some higher plants for their toxicity against soil borne pathogens

Abstract: Out of the leaf juices of eighteen plant species screened, only Eupatorium cannabinum exhibited complete toxicity against Pythium debaryanum, Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii. Shade drying of the leaves had no adverse effect, while oven drying produced an adverse effect on the fungitoxicity of the leaves of E. cannabinum. The crude leaf juice of E. cannabinum successfully inhibited damping-off (Fusarium oxysporum) infection of Pisum sativum seedlings.