Evaluation of Losses in Alfalfa Hay Production Caused by Crown Rot

Hawn, E. J.; Berkenkamp, W. B.; Lebeau, Julie

doi:10.1080/07060668109501391

Cited by 6 publications

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“…falcata background than in lines where M. sativa subsp. sativa predominated (Hawn et al, 1981;Wilcoxson et al, 1977).…”

Section: •G_mentioning

confidence: 98%

“…Cormack (1942) noted that crown rot infection had little direct impact on plant performance. In another study, treatment with mercuric fungicides increased alfalfa forage yield, but also increased crown rot and infection of crown buds with Fusarium spp., especially at temperatures just above freezing (Hawn et al, 1981). This suggests that soilborne pathogens not involved in crown rot were controlled by the fungicide, and implies that crown rot has little direct effect on yield.…”

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confidence: 99%

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Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: II. Crown Rot

Gossen

1994

Agronomy Journal

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Decline in stand density and productivity of alfalfa (Medicago sativa L.) over time in Canada and the USA has been attributed, in part, to crown and root diseases. In 1985, an experiment was initiated at three locations in Saskatchewan to examine the interaction of (i) harvest frequency, (ii) alfalfa cultivar, (iii) inoculation with fungal crown rot pathogens (Coprinus psychromorbidus, Phoma sclerotwides, or Fusarium spp.), and (iv) K nutrition on the etiology, lesion initiation, incidence, and severity of crown rot of alfalfa. Plant samples were collected from the plots in early spring and late fall each year, starting 1 yr after seeding. The pattern of symptom initiation and lesion expansion were similar at all sites. Lesions were observed initially at the base of senescing stems, and spread laterally into the crown and vertically into the tap root. Lesions were observed on plants at all sites on the first sampling date ( > 70% of plants affected at Loon Lake and Saskatoon and 32% at Melfort), but severity was low. By the fall of the following year (1987), incidence was near 100% at all sites, and severity had increased markedly. Harvest frequency and K fertility did not affect crown rot at any location. Inoculation with C. psychromorbidus resulted in small increases in crown rot severity at two sites, but inoculation With the other pathogens had no effect. 'Nordica' al-Agriculture Canada Res. Stn., Published in Agron. J. 86:88-93 (1994). falfa was more resistant to crown rot than 'Beaver'. These results indicate that resistance to crown rot may be advantageous if longterm persistence is required, but resistance is not required in shortterm rotations. Also, crown rot and crown bud rot, two alfalfa diseases that have previously been described as distinct entities, appear to be a single disease complex, based on similarities in symptom development and the organisms associated with affected plants.

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“…falcata background than in lines where M. sativa subsp. sativa predominated (Hawn et al, 1981;Wilcoxson et al, 1977).…”

Section: •G_mentioning

confidence: 98%

mentioning

confidence: 99%

Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: II. Crown Rot

Gossen

1994

Agronomy Journal

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“…Several pathogens have been implicated in stand decline in the Canadian prairies. Crown rot of alfalfa is found throughout western Canada (Hawn, 1958;Hawn et al, 1981;Hwang et al, 1991). This disease has been associated with plant pathogens in the fungal genus Fusarium (Leath et al, 1971;Uddin and Knous, 1991), although its etiology is not completely understood.…”

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confidence: 99%

Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: I. Survival and Yield

et al. 1994

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Declining productivity in older alfalfa (Medicago sativa L.) stands is an important problem in the Canadian prairies. Field trials were established in 1985 at three locations in Saskatchewan to examine the interaction of (i) harvest frequency, (ii) two alfalfa cultivars, (iii) in· oculation with one of three fungal pathogens (Coprinus psychromor· bidus, Phoma sc/erotioides, or Fusarium spp.), and (iv) K fertilization on survival and forage yield of alfalfa. Harvest and inoculation treat· ments were initiated in 1986 and continued each year until the tests were terminated in [1989][1990]. Plants were dug in spring and fall each year, and total nonstructural carbohydrate levels in the crowns were assessed using near infrared spectroscopy. Differences in plant nom· bers, stand density, persistence, and vigor between 'Nordica' (selected for resistance to C. psychromorbidus) and 'Beaver' were small. Harvest at 10% bloom (2-3 cuts) did not result in consistent reductions in numbers of plants, stand density, or total nonstructural carbohydrates relative to a single-cut treatment. Frequent harvest reduced vigor and first-cut yield of both cultivars in the year following the treatment, but caused larger reductions for Beaver than for Nordica. Total yields for the frequent harvests over all locations and treatments were 43% higher than for the single-cut treatment (5.3 vs. 3.7 Mg ha-1 ). Potas· sium fertility and inoculation with fungal pathogens had minimal im· pact on plant survival and yield. In conclusion, interactions among the factors which cause stand decline were minimal, and the reductions in plant vigor and first-cut yield resulting from frequent harvest were more than offset by the yield from late-season harvests.Abbreviations: TNC, total nonstructural carbohydrates.

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“…Traquair), in which lesions penetrate towards the center from the edge of the crown and do not extend into the taproot (Gossen et al, 1992). Crown rot has little direct effect on yield (Cormack, 1942;Gossen et al, 1994;Hawn et al, 1981); however, information on disease reaction among cultivars and about the impact of the disease on stand persistence is very limited.…”

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Development of Secondary Crowns Reduces Crown Rot Severity in Alfalfa Cultivars

Gossen

1998

Agronomy Journal

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Crown rot occurs wherever alfalfa (Medicago sativa L.) is grown, but the disease reaction of cultivars has rarely been examined. Differences in crown rot reaction among cultivars were followed for up to 9 yr in two studies. In one study, crown rot severity in nine alfalfa cultivars was assessed at Saskatoon (1985–1993) and at Outlook (irrigated test; 1986–1991) in Saskatchewan, Canada. From 1986 to 1991, there were no consistent differences in severity among cultivars. Crown rot symptoms were severe in almost every plant of every cultivar by 1991, so the trial at Outlook was discontinued. When the trial at Saskatoon was sampled in 1993, cultivars with more of a subsp. falcata background had less crown rot than those with subsp. sativa parentage. The primary crowns of most plants had been consumed with rot, but secondary crowns had formed in many plants. As a result, crown rot severity (rated mainly on secondary crowns) had declined substantially. To determine if these observations were consistent between trials, a second trial at Saskatoon (seeded 1985) was sampled in 1994. The same pattern was observed; crown rot severity was substantially lower 9 yr after establishment than at 5 yr, and the reduction was associated with development of secondary crowns. Forage yields in this mature stand were higher than early in the life of the stand, indicating that moderate levels of crown rot do not affect yield. Differences in disease reaction among cultivars were small, but may affect the development of secondary crowns, which allows alfalfa plants to compensate for progressive injury to the primary crown.

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Evaluation of Losses in Alfalfa Hay Production Caused by Crown Rot

Cited by 6 publications

References 6 publications

Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: II. Crown Rot

Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: II. Crown Rot

Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: I. Survival and Yield

Development of Secondary Crowns Reduces Crown Rot Severity in Alfalfa Cultivars

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