Alternaria alternantherae From Alligatorweed Also is Pathogenic on Ornamental Amaranthaceae Species

Holcomb, G. E.

doi:10.1094/phyto-68-265

Cited by 10 publications

(6 citation statements)

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“…(), A. alternantherae was pathogenic to Alternanthera philoxeroides (alligator weed; Gomphrenoideae), C. argentea , B. vulgaris , S. oleracea and Portulaca halimoides (silkcotton purslane; Portulacaceae), but not to Alternanthera ficoidea (sanguinaria; Gomphrenoideae), Amaranthus spinosus (spiny amaranth; Amaranthoideae), G. globosa or Pfaffia paniculata (suma; Gomphrenoideae). According to Holcomb (), A . alternantherae was strongly pathogenic to C .…”

Section: Discussionmentioning

confidence: 99%

Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species ofAlternariafromJapan

Nishikawa¹,

Nakashima

2013

Journal of Phytopathology

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Alternaria fungi are important plant pathogens. Here, we identified three species new to the Japanese mycoflora: Alternaria celosiae, Alternaria crassa and Alternaria petroselini. We proposed a new name for A. celosiae (E.G. Simmons & Holcomb) Lawrence, Park & Pryor, a later homonym of A. celosiae (Tassi) O. S avul. To characterize these and a fourth morphological taxon, Alternaria alstroemeriae, which was recently added to Japan's mycoflora, an integrated species concept was tested. We determined the host range of each isolate using inoculation tests and analysed its phylogenetic position using sequences of the internal transcribed spacer rDNA. The pathogenicity of our A. alstroemeriae isolate was strictly limited to Alstroemeria sp. (Alstroemeriaceae), but the species was phylogenetically indistinguishable from other small-spored Alternaria. Alternaria celosiae on Celosia argentea var. plumosa (Amaranthaceae) was also pathogenic to Amaranthus tricolor, to Alternanthera paronychioides and weakly to Gomphrena globosa (all Amaranthaceae) and formed a clade with the former Nimbya celosiae. Alternaria crassa on Datura stramonium (Solanaceae) was also pathogenic to Brugmansia 9 candida and Capsicum annuum in Solanaceae, but not to other confamilial plants; phylogenetically it belonged to a clade of large-spored species with filamentous beaks. Morphological similarity, phylogenetic relationship and experimental host range suggested that A. crassa, Alternaria capsici and Alternaria daturicola were conspecific. Alternaria petroselini on Petroselinum crispum (Apiaceae) was pathogenic to five species in the tribe Apieae as well as representatives of Bupleureae, Coriandreae, Seliaeae and Scandiceae in Apiaceae. Both phylogeny and morphology suggested conspecificity between A. petroselini and Alternaria selini.

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Section: Discussionmentioning

confidence: 99%

Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species ofAlternariafromJapan

Nishikawa¹,

Nakashima

2013

Journal of Phytopathology

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“…(Amaranthaceae; Alligatorweed) has been mostly successful along the Gulf coast of the US, where winters are warm and its primary control agent, Agasicles hygrophila Selman and Vogt (Coleoptera: Chrysomelidae; Alligatorweed Flea Beetle), overwinters successfully (Buckingham 1996, Coulson 1977, Vogt et al 1992. In 1975, the pathogenic fungus, Alternaria alternantherae Holcomb & Antonop., was discovered producing characteristic purple leaf lesions on Alligatorweed plants near Baton Rouge, LA (Holcomb 1978, Holcomb andAntonopoulos 1976,). Subsequent studies found A. alternantherae to be highly damaging to Alligatorweed plants but posed a risk to several non-target species (Barreto and Torres 1999, Holcomb 1978, Pomella et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal variability of the Alligatorweed pathogen, Alternaria alternantherae, in Louisiana

Harms¹,

Shearer²

2022

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Alligatorweed leaf spot is a disease of invasive Alternanthera philoxeroides (Alligatorweed) in the southern US, caused by Alternaria alternantherae. However, little is known about when or where this pathogen naturally occurs. To better understand this species’ life history, we examined temporal (every 2–3 weeks) and spatial (latitudinal) patterns of A. alternantherae occurrence at sites in Louisiana for 2 y. Pathogen presence reflected clear within-year temporal and spatial patterns. Overall, the percentage of leaves infected with A. alternantherae was low during spring each year (0–20% infected) but increased throughout summer (maximum of 50% infected), and plants in northern sites had lower frequency of infection relative to southern sites until later in the year (late summer/early fall) but only in 1 of the 2 years of our study. The mean proportion of leaves infected with A. alternantherae declined with latitude both years (P = 0.01) and variability increased with latitude (P = 0.04), a pattern suggestive of range limitation in northern areas. We estimate a northern distributional limit of 34°N for A. alternantherae in Louisiana, but Alligatorweed occurs farther north. Although we did not directly examine disease impacts to Alligatorweed during the study, they may be greatest in southern areas, where the pathogen is more common early and throughout the growing season, and thus may be less likely to provide control in northern infestations of the invasive Alligatorweed.

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“…In 1976, a fungal pathogen identified as Alternaria alternantherae ( Figure 2) was discovered on A. philoxeroides plants near Baton Rouge, LA (Holcomb and Antonopoulos 1976). The fungus develops small purple lesions on leaves, which become necrotic over time, leading to leaf senescence and abscission from the plant (Holcomb 1978). Although A. alternantherae can be quite damaging when infection rate is high, it was found to infect a number of ornamental species, so its value as a classical biological control agent is equivocal (Holcomb 1978;Pomella et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…The fungus develops small purple lesions on leaves, which become necrotic over time, leading to leaf senescence and abscission from the plant (Holcomb 1978). Although A. alternantherae can be quite damaging when infection rate is high, it was found to infect a number of ornamental species, so its value as a classical biological control agent is equivocal (Holcomb 1978;Pomella et al 2007). However, the combined use of pathogen application and introduction of the flea beetle has not been attempted, though they are commonly observed affecting the same plants in field settings (Harms and Shearer 2019).…”

Section: Introductionmentioning

confidence: 99%

A first examination of the interaction between Alternaria alternantherae and Agasicles hygrophila on Alternanthera philoxeroides

Harms¹,

Shearer²

2020

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The use of an alligatorweed (Alternanthera philoxeroides) insect biological control agent, alligatorweed flea beetle (Agasicles hygrophila Selman and Vogt), and the leaf spot plant pathogen, alligatorweed leaf pathogen (Alternaria alternantherae Holcomb and Antonopoulis), may provide enhanced control of alligatorweed infestations if competitive interactions between agents are minimal and damage to host plants are synergistic. However, to assess suitability of co-use of these two agents, it is necessary to first identify whether introduction of one may impact performance of the other. This technical note details a first examination of competitive interactions between A. hygrophila and A. alternantherae under varied temperature and host nutritional conditions. Presented are the results of laboratory experimentation and recommendations for future research.

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Alternaria alternantherae From Alligatorweed Also is Pathogenic on Ornamental Amaranthaceae Species

Cited by 10 publications

References 0 publications

Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species ofAlternariafromJapan

Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species ofAlternariafromJapan

Spatial and temporal variability of the Alligatorweed pathogen, Alternaria alternantherae, in Louisiana

A first examination of the interaction between Alternaria alternantherae and Agasicles hygrophila on Alternanthera philoxeroides

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