Studies on the epidemiology of <i>Alternaria brassicicola</i> in <i>Brassica oleracea</i> seed production crops

Humpherson-Jones, F. M.; Maude, R. B.

doi:10.1111/j.1744-7348.1982.tb07192.x

Cited by 45 publications

(24 citation statements)

References 4 publications

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“…Wilts, was isolated from infected winter oilseed rape plants using the methods of Humpherson-Jones & Maude (1982a). Single spore isolates were established on potato dextrose agar (PDA) and maintained at 25 °C.…”

Section: Alternaria Brassicicolamentioning

confidence: 99%

TOWARDS THE SELECTION IN VITRO FOR RESISTANCE TO ALTERNARIA BRASSICICOLA (SCHW.) WILTS., IN BRASSICA NAPUS SSP. OLEIFERA (METZG.) SINSK., WINTER OILSEED RAPE

Macdonald

Ingram

1986

New Phytologist

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SUMMARY Culture filtrates of Alternaria brassicicola (Schw.) Wilts, were found to be toxic to secondary embryoids of Brassica napus ssp. oleifera (Metzg.) Sinsk. The culture filtrates were partially purified and added to tissue culture media to produce a selection medium. Different secondary embryoid lines of B. napus were found to differ in their sensitivity to the selection medium, and it was possible to select lines which showed increased resistance to the selection medium. Some plants that were regenerated from secondary embryoids were found to be more resistant to the pathogen than were seed‐grown plants of the same cultivar, although there was no correlation between sensitivity to the selection medium and susceptibility to the pathogen.

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Section: Alternaria Brassicicolamentioning

confidence: 99%

TOWARDS THE SELECTION IN VITRO FOR RESISTANCE TO ALTERNARIA BRASSICICOLA (SCHW.) WILTS., IN BRASSICA NAPUS SSP. OLEIFERA (METZG.) SINSK., WINTER OILSEED RAPE

Macdonald

Ingram

1986

New Phytologist

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“…linicola conidia, strong winds may remove a large proportion of the available reserves of conidia within a short time. The pattern of diurnal dispersal of A. linicola conidia is therefore similar to that of other Alternaria species, including A. alternata [Pearson and Hall, 1975], A. brassicicola [Humpherson-Jones and Maude, 1982], A. dauci [Langenberg et al, 1977] and A. porri f. sp. solani [Rotem, 1964].…”

Section: Discussionmentioning

confidence: 64%

“…The greatest concentrations in the air above linseed crops in 1990 were collected in July and August and coincided with an increase in the disease incidence in the senescent crops [Fitt and Ferguson, 1993]. The dispersal of conidia of many Alternaria species has been reported to follow seasonal and diurnal periodicities [Humpherson-Jones and Maude, 1982;Langenberg et al, 1977;Meredith, 1966;Rotem, 1964Rotem, , 1991. The highest concentrations of air-borne Alernaria conidia are often observed late in the growing season, with the maximum numbers being dispersed at midday.…”

Section: Introductionmentioning

confidence: 99%

“…The highest concentrations of air-borne Alernaria conidia are often observed late in the growing season, with the maximum numbers being dispersed at midday. However, most of these conidia are transported for only short distances from the foci of their production and therefore can create only local epidemics [Bashan et al, 1991;Humpherson-Jones and Maude, 1982].…”

Section: Introductionmentioning

confidence: 99%

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Periodicity and gradients in dispersal ofAlternaria linicola in linseed crops

1995

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Conidia of Alternaria linicola produced on infected linseed crops were mainly dispersed by wind. The numbers of conidia in the air above linseed crops collected by a Burkard spore sampler were greatest between 12:00 h and 13:00 h, when the relative humidity was lowest. Although numbers of conidia collected decreased with increasing height within and above the crop canopy, air-borne A. linicola conidia were present up to 80 cm above the crop canopy. Conidia of A. linicola were transported by wind up to at least 40 m downwind from an artificial line inoculum source, but their numbers decreased with increasing distance from the source. In 1991In , 1992In , and 1993, the dispersal of A. linicola conidia above linseed crops followed a seasonal periodicity which was influenced by weather conditions and cultural practices. The greatest numbers of conidia were collected during July, August and early September and coincided with periods favourable for sporulation and with an increase in the incidence of the disease in the senescent crop. Air-borne A. linicola conidia produced on point or line inoculum sources (naturally infected linseed stern'debris) were responsible for the spread of the disease in linseed crops. In 1992 and 1993, the disease was first detected downwind from the sources, but by the end of the growing seasons, it had spread in all directions and up to 20 m and 60 m from the sources, respectively. Disease gradients were initially steep near the inoculum sources but they became flatter with time due to the secondary spread of the disease.

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“…The production of vegetable brassicas overlaps with periods when the oilseed rape crop is maturing prior to harvest and when diseases are often abundant. During the oilseed rape harvest fungal pathogens can be dispersed over considerable distances (Humpherson-Jones & Maude, 1982).…”

Section: R Kennedy Et Al 304mentioning

confidence: 99%

Production and immunodetection of ascospores of Mycosphaerella brassicicola: ringspot of vegetable crucifers

Kennedy¹,

Wakeham²,

Cullington³

1999

Plant Pathology

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Pseudothecia containing abundant ascospores of Mycosphaerella brassicicola were produced in vitro on Brussels sprout decoction agar at 15ЊC under a 16-hour photoperiod of different light regimes. Spermogonia containing spermatia were also produced on the decoction agar. Ascospores were released when cultures were misted with SDW and placed under continuous light. Germination of ascospores was highest between 20ЊC and 25ЊC and spores remained viable at relative humidities above 93·5%. Exposure of ascospores to 55% relative humidity for 24 h reduced their germination to 75%. A polyclonal antiserum raised against whole ascospores was used to detect, by immunofluorescence, the ascospore and mycelial wall of M. brassicicola, following reaction with anti-rabbit IgG FITC conjugate. Autofluorescence of spore and mycelial components of other fungal species could be eliminated using the counterstains Evan's blue and eriochrome black at 0·2% and 0·5%, respectively, in phosphate buffered saline (pH 7·2). A procedure was developed to detect, by immunofluorescence, ascospores of M. brassicicola on artificially inoculated Melinex spore tape. Coating of the spore tape with bovine serum albumin provided a suitable support medium and blocking agent for detection of ascospores in the field. The potential use of the system for selective detection of ascospores of M. brassicicola in infected crops of vegetable brassicas in the presence of other ascosporic fungi is discussed.

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Studies on the epidemiology of Alternaria brassicicola in Brassica oleracea seed production crops

Cited by 45 publications

References 4 publications

TOWARDS THE SELECTION IN VITRO FOR RESISTANCE TO ALTERNARIA BRASSICICOLA (SCHW.) WILTS., IN BRASSICA NAPUS SSP. OLEIFERA (METZG.) SINSK., WINTER OILSEED RAPE

TOWARDS THE SELECTION IN VITRO FOR RESISTANCE TO ALTERNARIA BRASSICICOLA (SCHW.) WILTS., IN BRASSICA NAPUS SSP. OLEIFERA (METZG.) SINSK., WINTER OILSEED RAPE

Periodicity and gradients in dispersal ofAlternaria linicola in linseed crops

Production and immunodetection of ascospores of Mycosphaerella brassicicola: ringspot of vegetable crucifers

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