Multiple Species of Asteraceae Plants are Susceptible to Root Infection by the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum

Plant Disease ◽  
2021 ◽  
Author(s):  
William Underwood ◽  
Michelle A. Gilley ◽  
Christopher G. Misar ◽  
Thomas J. Gulya ◽  
Gerald J. Seiler ◽  
...  

The necrotrophic fungal pathogen Sclerotinia sclerotiorum can cause disease on numerous plant species, including many important crops. Most S. sclerotiorum-incited diseases of crop plants are initiated by airborne ascospores produced when fungal sclerotia germinate to form spore-bearing apothecia. However, basal stalk rot of sunflower occurs when S. sclerotiorum sclerotia germinate to form mycelia within the soil which subsequently invade sunflower roots. To determine if other plant species in the Asteraceae family are susceptible to root infection by S. sclerotiorum, cultivated sunflower (Helianthus annuus L.) and seven other Asteraceae species were evaluated for S. sclerotiorum root infection by inoculation with either sclerotia or mycelial inoculum. Additionally, root susceptibility of sunflower was compared to that of dry edible bean and canola, two plant species susceptible to S. sclerotiorum but not known to display root-initiated infections. Results indicated that multiple Asteraceae family plants are susceptible to S. sclerotiorum root infection after inoculation with either sclerotia or mycelium. These observations expand the range of plant hosts susceptible to S. sclerotiorum root infection, elucidate differences in root inoculation methodology, and emphasize the importance of soil-borne infection to Asteraceae crop and weed species.

2008 ◽  
Vol 9 (1) ◽  
pp. 041 ◽  
Author(s):  
Rogério Luiz BACKES ◽  
Adriano Martinho de SOUZA ◽  
Alvadi Antonio BALBINOT JUNIOR ◽  
Gilson José Marcinichen GALLOTTI ◽  
Alvimar BAVARESCO

O cultivo de girassol (Helianthus annuus) tem se mostrado uma nova opção econômica em diversas regiões do Brasil. O crescimento na área de cultivo se deve ao fomento conseqüente ao Programa Nacional de Biodiesel. Assim, o objetivo deste trabalho foi avaliar a produtividade de aquênios e alguns caracteres de importância agronômica em cultivares de girassol semeado em duas épocas de safrinha no Planalto Norte Catarinense. Foram realizados dois experimentos no município de Papanduva/Planalto Norte Catarinense. O delineamento experimental foi de blocos casualizados com três repetições. Foram avaliadas 12 cultivares na primeira época de semeadura (janeiro) e 13 na segunda época (fevereiro). Verificaram-se diferenças entre cultivares quanto ao ciclo até a maturação de colheita, que variou de 93 a 107 dias, de acordo com a cultivar e época de semeadura. Na segunda época houve altos índices de acamamento (até 29%) e quebra de plantas (até 42%) em algumas cultivares. Na primeira época 10,8% dos capítulos foram infectados com Sclerotinia sclerotiorum. Na segunda época este percentual aumentou para 45%, fator que influenciou a produtividade média obtida, de 1861 e 618 kg ha-1, na primeira e na segunda época, respectivamente.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0237894
Author(s):  
Amy E. Kendig ◽  
Vida J. Svahnström ◽  
Ashish Adhikari ◽  
Philip F. Harmon ◽  
S. Luke Flory

Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.


Weed Science ◽  
1988 ◽  
Vol 36 (3) ◽  
pp. 329-334 ◽  
Author(s):  
John Gardina ◽  
Robert H. Littrell ◽  
Richard T. Hanlin

Greenhouse and growth chamber studies were conducted to determine conditions for infection of the fungal pathogenColletotrichum truncatum(Schw.) Andrus and Moore on Florida beggarweed (Desmodium tortuosum(Sw.) DC. # DEDTO and to determine the host specificity of this fungus. Optimum conditions for disease development were 14 to 16 h incubation in 100% relative humidity (RH) at 24 to 29 C. Control of Florida beggarweed with 105to 107C. truncatumspores/ml was greatest in the cotyledon stage and decreased with plant age. Ten of 18Desmodiumspecies tested were susceptible to the Florida beggarweed isolate ofC. truncatumbut 13 other plant species and varieties were resistant and 61 were immune.


2013 ◽  
Vol 14 (1) ◽  
pp. 8 ◽  
Author(s):  
S. Sanogo ◽  
J. Schroeder ◽  
S. Thomas ◽  
L. Murray ◽  
N. Schmidt ◽  
...  

The chile pepper (Capsicum annuum) crop is affected by several pests, pathogens, and weeds including Verticillium dahliae, Meloidogyne incognita, spurred anoda (Anoda cristata), Wright groundcherry (Physalis acutifolia), and tall morningglory (Ipomoea purpurea). These weed species are unimpaired hosts to V. dahliae and M. incognita. Chile plants have been found co-infected with V. dahliae and M. incognita in commercial fields. Greenhouse studies were conducted to determine the relationships among V. dahliae, M. incognita, and each of the four aforementioned plant species. Plants were either non-inoculated or inoculated with V. dahliae, M. incognita, or V. dahliae plus M. incognita. Six weeks after inoculation, plant infection by V. dahliae, M. incognita reproduction, plant height and biomass were measured. Three relationships were identified: V. dahliae was recovered from 100% of all four inoculated plant species, irrespective of M. incognita treatment; V. dahliae and M. incognita enhanced or had no effect on weed biomass but were pathogenic to chile; and co-infection by V. dahliae had no effect on nematode reproduction in the first M. incognita generation on the crop or weeds. These biological relationships suggest that the competitive impact of the weeds may increase and pathogen diversity may be affected in infested fields, ultimately impacting the efficacy of our common IPM tools. Accepted for publication 17 July 2013. Published 20 September 2013.


1993 ◽  
Vol 73 (1) ◽  
pp. 265-272 ◽  
Author(s):  
S. J. Park

White mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important disease in common bean (Phaseolus vulgaris L.) production areas. It reduces seed yield and lowers the quality of beans. Development of the disease is thought to be affected by plant canopy type (architecture), and by genetic resistance. This study determined the effect of plant type and row width on white mold and seed yield. Three short bush/vine and four semi-determinate upright genotypes were tested in narrow (30 cm) and wide (60 and 80 cm) rows for 2 yr in a field prone to white mold development. Incidence and disease index increased as row width became narrower. The upright type was infected less than the short bush type. Ex Rico 23, which is a short vine, open canopy type, was moderately resistant to the mold. A tall upright selection, A55, showed the lowest mold infection; it was significantly less than that of Ex Rico 23. Seed yield of all genotypes increased as row width decreased even though there was an increase in white mold incidence. Stiff-strawed upright types had less lodging. To reduce white mold, cultivars should have lodging resistance, narrow canopied upright plant type and genetic resistance. Development of the upright plant types allows for narrow-row production and direct combining. Key words: Dry edible bean, Phaseolus vulgaris, white mold, Sclerotinia sclerotiorum, plant type, row width, seed yield


2006 ◽  
Vol 28 (1) ◽  
pp. 27 ◽  
Author(s):  
A. C. Grice

Most parts of the Australian rangelands are at risk of invasion by one or more species of non-native plants. The severity of current problems varies greatly across the rangelands with more non-native plant species in more intensively settled regions, in climatic zones that have higher and more reliable rainfall, and in wetter and more fertile parts of rangeland landscapes. Although there is quantitative evidence of impacts on either particular taxonomic groups or specific ecological processes in Australian rangelands, a comprehensive picture of responses of rangeland ecosystems to plant invasions is not available. Research has been focused on invasive species that are perceived to have important effects. This is likely to down play the significance of species that have visually less dramatic influences and ignore the possibility that some species could invade and yet have negligible consequences. It is conceivable that most of the overall impact will come from a relatively small proportion of invasive species. Impacts have most commonly been assessed in terms of plant species richness or the abundance of certain groups of vertebrates to the almost complete exclusion of other faunal groups. All scientific studies of the impacts of invasive species in Australian rangelands have focused on the effects of individual invasive species although in many situations native communities are under threat from a complex of interacting weed species. Invasion by non-native species is generally associated with declines in native plant species richness, but faunal responses are more complex and individual invasions may be associated with increase, decrease and no-change scenarios for different faunal groups. Some invasive species may remain minor components of the vegetation that they invade while others completely dominate one stratum or the vegetation overall.


2008 ◽  
Vol 24 (05) ◽  
pp. 477-484 ◽  
Author(s):  
Tuanjit Srithongchuay ◽  
Sara Bumrungsri ◽  
Ekapong Sripao-raya

Abstract:Although plant species that attract multiple species of pollinators predominate in tropical plant communities, pollination specialists appear to be at a greater advantage in tropical ecosystems in which pollinators are numerous and many plants flower synchronously. The present study determined the breeding system and legitimate pollinators ofOroxylum indicumVent. in Songkhla and Patthalung Provinces, Thailand.Oroxylum indicumexhibits steady-state flowering, with one or two flowers per inflorescence opening each night. Flowers open in the evening and drop off shortly after midnight, while its bilabiate stigma is highly sensitive, and quickly close upon being touched.Oroxylum indicumis self-incompatible. Hand-cross pollination and open pollination yielded the highest pollination success (47.7% and 31.2% respectively, n = 7 trees). About 900 pollen grains are needed for initiating fruit set. It is confirmed that a fruit bat,Eonycteris spelaea, is the legitimate pollinator. Bats are responsible for all pollen load and the pollen load from only one visit is generally sufficient to initiate fruit set. AlthoughEonycteris spelaeais effective, it is an inefficient pollinator. Compared with plant species pollinated by multiple animal species, the likelihood of pollination failure resulting from the decline in populations ofEonycteris spelaeawill be much more intense inOroxylum indicum.


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