Survival of <i>Cochliobolus sativus</i> conidia in pure culture and in natural soil at different relative humidities

Ledingham, R. J.

doi:10.1139/b70-275

Cited by 9 publications

(8 citation statements)

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“…Although there are reports of survival of B. sorokiniana conidia in soil for 8 months (Ledingham, 1970) or even for more than a year (Chin and Tinline, 1963;Ries and Santos, 1987), the conditions in the monsoon climate of the Indian subcontinent are quite different. In the rice-wheat cropping region of India, covering 10.5 million ha, the monsoon arrives during late June or early July and from here onwards, water-logged conditions arise in the rice fields.…”

Section: Discussionmentioning

confidence: 99%

Sources of inoculum and reappearance of spot blotch of wheat in rice?wheat cropping

Pandey

Kumar

et al. 2005

Eur J Plant Pathol

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A study was undertaken to examine the main source of inoculum of Bipolaris sorokiniana responsible for its reappearance in rice-wheat cropping regions of eastern India. Soil samples were collected at monthly intervals during April-October in the years 2000 and 2001 from fields having rice-wheat cropping. Bipolaris sorokiniana conidia were isolated and their viability was found to decline sharply with the onset of flooding in the month of August. In contrast to 82% in April, viability was 4% and <1% in August and September, respectively. Viable conidia were multiplied in the laboratory and inoculated on to susceptible cv. Sonalika under controlled conditions for test of pathogenicity. Appearance of symptoms typical to spot blotch were recorded after 7 days. Twenty-two different species (weeds and grasses) normally found to be associated with rice-wheat fields were tested for the presence of B. sorokiniana to evaluate their possible role as alternative hosts. Only three species, i.e. Setaria glauca, Echinochloa colonum and Pennisetum typhoids, were found to naturally harbour B. sorokiniana. Isolates from these hosts were tested for pathogenicity and also for their possible spread to wheat. When reisolated from these hosts, the pathogen did not infect wheat. Seeds of 25 different wheat genotypes were tested for B. sorokiniana infection. All genotypes were infected and the incidence of infection varied from 26% to 86%. Five isolates of wheat and one isolate from each of the three species (S. glauca, E. colonum and P. typhoids) were subjected to RAPD analysis. Two broad clusters were formed, suggesting that the wheat isolates were different from the isolates originating from other hosts. The results indicate that seeds are the most important source of inoculum for the reappearance of spot blotch of wheat in rice-wheat cropping systems in eastern India.

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Section: Discussionmentioning

confidence: 99%

Sources of inoculum and reappearance of spot blotch of wheat in rice?wheat cropping

Pandey

Kumar

et al. 2005

Eur J Plant Pathol

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“…Furthermore, although the efficiency of this method was only 56% as compared to that of 98% reported by Chinn et al (I960), the technique was much more rapid. Chinn and Ledingham (f 958) found that the viability of spores recovered from stubble in a summerfallow field diminished with time, and Ledingham (1970) showed that high humidity decreased conidial viability in soil. These reports provide a possible explanation for the lower viability in deep than in shallow soil profiles because soils at the lower profiles would have a consistently higher moisture content and probably would also contain older conidia.…”

Section: Resultsmentioning

confidence: 99%

“…In these and other studies (Chinn 1965, 1976a, Ledingham 1961) only samples collected from near the surface, usually 0-7.6 cm, were examined for conidial populations. Ledingham (1970) found spore viability was lower in soils held at higher relative humidities and suggested viability would decrease if conidia were buried in soil, but Chulkina (1972Chulkina ( , 1974 reported a higher viability of conidia in the subsoil than in surface soils. Under trash maintenance cultivation in Russia, there were more conidia in surface soils (0-10cm) than in subsurface soils (I0-20cm) (Chulkina 1972, Shevtsov & Okhinko 1976.…”

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confidence: 99%

Number and viability of conidia ofCochliobolus sativusin soil profiles in summerfallow fields in Saskatchewan

Duczek

1981

Canadian Journal of Plant Pathology

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“…Inoculum density in the soil is related to the amount of fungal spoliation occurring on crop residues (Reis & Wunsche 1984). Under favourable conditions the conidia of B. sorokiniana may survive several years in field soil (Ledingham 1970). Oil crops and fallow in crop rotation significantly decrease the number of germinating conidia in the soil (Chinn 1976).…”

Section: Introductionmentioning

confidence: 99%

Reaction of spring barley cultivars grown in Finland to soil-borne infection by Bipolaris sorokiniana and to its toxic metabolites

Kurppa

1985

AFSci

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Abstract. Soil-borne infection of Bipolaris sorokiniana caused foot and root rot in all spring barley cultivars studied. Significant differences in susceptibility of the cultivars and pathogenicity of the fungus isolates were found. Primary symptoms caused by the fungus were seedling blight, later foot and root rot. Yield losses caused by the fungus varied from 3 % to 33 % the mean being c. 15 %. Yield losses could occur without severe disease symptoms. Toxic metabolites produced by the fungus induced visible foot and root symptoms in all cultivars tested and caused lesions in the leaves of some cultivars. Variability in toxin production of fungus isolates as well as the reaction of a cultivar to toxins was demonstrated. The cultivars most susceptible to soil-borne infection by the fungus also showed the most severe symptoms when exposed to toxic metabolites of the fungus.

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Survival of Cochliobolus sativus conidia in pure culture and in natural soil at different relative humidities

Cited by 9 publications

References 0 publications

Sources of inoculum and reappearance of spot blotch of wheat in rice?wheat cropping

Sources of inoculum and reappearance of spot blotch of wheat in rice?wheat cropping

Number and viability of conidia ofCochliobolus sativusin soil profiles in summerfallow fields in Saskatchewan

Reaction of spring barley cultivars grown in Finland to soil-borne infection by Bipolaris sorokiniana and to its toxic metabolites

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