Seedling Blight of Sicklepod Caused by<i>Alternaria cassiae</i>

Walker, H. L.

doi:10.1094/pd-66-426

Cited by 52 publications

(41 citation statements)

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“…Such anomaly has been demonstrated for other fungi, as in the case of Alternaria cassiae Jurair & A. Khan, a fungus belonging to a genus related to Nimbya. Among 30 plant species in nine families that were screened against A. cassiae, phytotoxity was observed initially on some plants, but only low disease incidence was obtained when the trial was repeated with the application of a low inoculum concentration (Walker, 1982). Apart from members of the Amaranthaceae, N. alternantherae was able to sporulate and be recovered only from dead leaves of spinach (Spinacia oleracea).…”

Section: Discussionmentioning

confidence: 99%

Nimbya alternantherae a potential biocontrol agent for alligatorweed, Alternanthera philoxeroides

2006

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Alligatorweed, (Alternanthera philoxeroides (Mart.) Griseb.), an aquatic and wetland plant native to South America, is an aggressive weed in many parts of the world. Its ability to compete with other native plants and to impede waterways has made it a serious threat to aquatic ecosystems. Although biological control with insects has been fairly successful in aquatic habitats, there is a need for additional agents to manage the weed in upland sites. Accordingly, in a survey in Brazil in 1997 a fungus, Nimbya (=Alternaria) alternantherae (Holcomb and Antonopoulus) Simmons and Alcorn, was discovered and confirmed to be highly damaging to alligatorweed. Studies were conducted to determine the potential of this fungus for controlling this weed. Several isolates from Brazil, USA, and Puerto Rico were compared and no differences in virulence were observed, although a lower dew requirement was demonstrated for the Brazilian isolates. Conidia were more effective than mycelial suspension, and inoculum concentrations of 1 · 10 5 and 1 · 10 6 conidia per ml provided significant levels of control of the weed in greenhouse and field experiments, respectively. In a host-range study, N. alternantherae infected 6 plant species from a total of 42 species belonging to 23 families. N. alternantherae has the potential to be an effective mycoherbicide for alligatorweed.

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Section: Discussionmentioning

confidence: 99%

Nimbya alternantherae a potential biocontrol agent for alligatorweed, Alternanthera philoxeroides

2006

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“…The pathogen has a narrow host-range and can cause stunting and death of inoculated sicklepod seedlings. Weed control of 60 to 100% is possible when the fungus is applied as a postemergence bioherbicide (Charudattan et ai., 1986;Walker, 1982). At least 8 hours of free water at 20 to 30°C are required for infection, however, older plants exhibit higher levels of resistance to this pathogen (Walker, 1982;Walker and Riley, 1982).…”

Section: Foliar Fungal Agentsmentioning

confidence: 99%

“…Weed control of 60 to 100% is possible when the fungus is applied as a postemergence bioherbicide (Charudattan et ai., 1986;Walker, 1982). At least 8 hours of free water at 20 to 30°C are required for infection, however, older plants exhibit higher levels of resistance to this pathogen (Walker, 1982;Walker and Riley, 1982). In regional field trials, the fungus gave similar or better levels of control than toxaphene, a chemical used for control of the weed in some states of U.S. (Charudattan et al, 1986).…”

Section: Foliar Fungal Agentsmentioning

confidence: 99%

Innovative Applications of Microbial Agents for Biological Weed Control

Boyetchko

1999

Biotechnological Approaches in Biocontrol of Plant Pathogens

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“…In greenhouse tests, A. cassiae infected showy crotalaria (Crotalaria spectabilis Roth.) and one other species of Cassia, coffee senna (Cassia occidentalis L.), but did not infect 30 other crop and weed species (Walker 1982). Thus far, there appears to be no other reports of Cass/a species tested for interactions with this organism.…”

Section: Introductionmentioning

confidence: 97%

The mycoherbicide Atlernaria cassiae infects and alters phenolic metabolism of Cassia alata seedlings

Hoagland

2005

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'994-10-11'; acceptée! 1995-09-13 The mycoherbicide Alternaria cassiae, a pathogen of the weed sicklepod (Cassia obtusifolia), was found to infect a previously untested Cassia species, Cassia alata (ringworm bush or seven golden candlesticks). When 2-wk-old, growth chamber-grown C. alata seedlings were inoculated with 10 5 spores mL 1 followed by a 12-h dew period, infection was apparent 16-20 h after treatment. Infection severity was proportional to spore concentration, and 10 6 spores mL 1 caused complète mortality 4-5 d after treatment. Plant âge was also a factor in disease severity and mycoherbicidal efficacy. At 10 6 spores mL 1 , 95% of 1-to 3-wk-old seedlings were killed (with severe damage to others); 3-to 4-wk-old plants had multiple lésions, growth réduction, and some leaf abscission; and 5-to 7-wk-old plants were infected with many lésions, but they outgrew thèse effects. Extractable phenylalanine ammonia-lyase in treated C. alata seedlings was increased three-fold above that of untreated seedlings 17-96 h after spore application. Soluble hydroxyphenolic levels were also increased in the A. cassiae-treated seedlings, but not until 48-96 h after treatment. Results indicate an expanded host range for this plant pathogen and suggest that phenolic metabolism is increased in défense of pathogen invasion. Le mycoherbicide Alternaria cassiae, un agent pathogène du Cassia obtusifolia a infecté le Cassia alata, une espèce de Cassia jamais testée auparavant. Quand des plantules de C. alata âgées de 2 semaines et cultivées en cabinets de croissance ont été inoculées avec 10 5 spores mL 1 suivi d'une période d'humectation de 12 h, l'infection était apparente 16-20 h après le traitement. La sévérité de l'infection était proportionnelle à la concentration de spores, 10 6 spores mL 1 entraînant une mortalité complète 4-5 jours après le traitement. L'âge des plantes influençait la gravité de la maladie et l'efficacité du mycoherbicide. À 10 6 spores mL 1 , 95 % des plantes âgées de 1-3 semaines étaient mortes, et les survivantes montraient des dommages graves; les plantes âgées de 3-4 semaines présentaient des lésions multiples, une réduction de croissance et une chute des feuilles. Finalement les plantes âgées de 5-7 semaines étaient infectées et présentaient plusieurs lésions mais elles ont repris le dessus sur la maladie. La quantité de phénylalanine-ammonia-lyase extractible des plantules de C. alata traitées était trois fois plus élevée que chez les plantules non traitées 17-96 h après l'application des spores. Les niveaux d'hydroxyphénols solubles étaient aussi plus élevés dans les plantules traitées Hoagland, R.E. 1995. Le mycoherbicide

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Seedling Blight of Sicklepod Caused byAlternaria cassiae

Cited by 52 publications

References 0 publications

Nimbya alternantherae a potential biocontrol agent for alligatorweed, Alternanthera philoxeroides

Nimbya alternantherae a potential biocontrol agent for alligatorweed, Alternanthera philoxeroides

Innovative Applications of Microbial Agents for Biological Weed Control

The mycoherbicide Atlernaria cassiae infects and alters phenolic metabolism of Cassia alata seedlings

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