Ventenata dubia’s native range and consideration of plant pathogens for biological control

AbstractVentenata [Ventenata dubia (Leers) Coss.] is a nonindigenous, invasive grass in the inland Pacific Northwest (PNW) of the United States. It appears to be present in the PNW without any evidence of disease expression. Surveys of V. dubia in the PNW (Idaho, Montana, Oregon, and Washington) were entirely negative for fungi, including types of pathogens that might be expected in grasses (e.g., rust, powdery mildew, choke). In Europe, where V. dubia is native, fungi were documented (i.e., Septoria ventenatae Sandu, Tilletia fusca Ellis & Everh., and Tilletia elisabethae T. Denchev & Denchev) on V. dubia. In its native range there likely are natural enemies that may limit V. dubia abundance, and these may include fungal pathogens. Pathogens of V. dubia from its native range may hold potential for use as classical biological control agents in North America, and if deemed safe, could be introduced. To ascertain V. dubia’s native range, we compiled data from herbarium specimens, consulted with herbarium curators in the region, and searched relevant literature. We found that V. dubia primarily is reported in southern Europe and western Asia. Ventenata dubia has been reported only occasionally from North Africa in Algeria and Morocco. The common name “North Africa grass” likely originated from references to V. dubia in the 19th-century botanical explorations in Algeria of the French botanist, Ernest Cosson, who published the current scientific name based on a preexisting name in 1854. Another finding of interest is that the latitudinal range of collections from Europe and North Africa of V. dubia spans Tunisia to Finland. The plant may thus be adapted to a range of environments, indicating it could become more widely distributed in North America. Efforts to search its native range for pathogens should also consider the range of environmental conditions found within its native and introduced ranges.

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First European Report of a Leaf Spot on Common Ragweed (Ambrosia artemisiifolia) Caused by a Phoma sp.

Plant Disease ◽

10.1094/pdis-93-7-0763b ◽

2009 ◽

Vol 93 (7) ◽

pp. 763-763 ◽

Cited By ~ 2

Author(s):

G. Bohár ◽

K. Varga Bohár ◽

A. Pintye ◽

L. Kiss

Keyword(s):

Biological Control ◽

North America ◽

Plant Pathogens ◽

Sequence Data ◽

Citrullus Lanatus ◽

The United States ◽

Ambrosia Artemisiifolia ◽

Its Sequences ◽

Common Ragweed ◽

Necrotic Spots

Common ragweed, native to North America, has recently become invasive in some parts of Europe. In Hungary, it has become the most widespread agricultural weed species and the most important producer of allergenic pollen since the 1990s. During surveys for its fungal plant pathogens to be evaluated as potential biological control agents (1), ragweed plants exhibiting necrotic spots on the leaves and stems were repeatedly found in Heves and Vas counties in Hungary in September 2004 and 2006. Numerous globose and ostiolate pycnidia, 68 to 115 μm in diameter, containing hyaline, unicellular conidia, 3 to 8 μm long, were found in necrotic tissues. On the basis of these characteristics, the fungus was identified as a Phoma sp., and 21 isolates were obtained on Czapek-Dox medium supplemented with 2% malt and 0.5% tetracycline in 2004 and 2006. Two well-sporulating isolates, designated Ph-5 and Ph-17, were selected for further studies. DNA was extracted from mycelium with a Qiagen DNeasy Plant Kit (Hilden, Germany) and the rDNA internal transcribed spacer (ITS) sequences were amplified and determined as described by Szentiványi et al. (2). The ITS sequences were identical in these two isolates and were 97 to 98% similar to those of Didymella bryoniae (anamorph Phoma cucurbitacearum), a pathogen of cucurbits, and also to those of other Phoma spp. No ITS sequences identical to those determined in Phoma isolates Ph-5 and Ph-17 were found in GenBank. Sequence data were deposited in GenBank (No. FJ794609). To test the pathogenicity of Ph-17 grown on Czapek-Dox medium with 2% malt, a 2 to 6 × 105 conidia/ml aqueous suspension was used to inoculate 2-month-old potted ragweed plants and 1-month-old cucumber cv. Rajnai fürtös, bottle gourd (Lagenaria leucantha) cv. Minibottle, and watermelon (Citrullus lanatus) cv. Sugar Baby, which were all grown from seeds in a greenhouse. Plants were kept in transparent plastic chambers for 6 weeks. Five pots with one to three plants each were used for each plant species tested and the experiment was carried out twice. Noninoculated plants, two pots with one to three individuals for each species kept in the same way, served as controls. Necrotic spots with pycnidia developed on 38 to 47% of the leaves of all inoculated ragweed plants 18 to 25 days after inoculation, whereas all the cucurbitaceous plants tested, as well as the control ragweed plants, did not develop disease symptoms. Although the Phoma isolate Ph-17 was, based on ITS sequence data, closely related to D. bryoniae, it was not pathogenic to cucurbits. The pathogen was reisolated from two diseased ragweed plants. Several Phoma spp. strains were isolated from Ambrosia artemisiifolia in the United States and Canada (3,4), but to our knowledge, none were isolated outside North America. One of the strains has already been used as a potential biological control agent of ragweed in Canada, but then lost its virulence in culture (3). The biocontrol potential of the Hungarian Phoma sp. isolate Ph-17 against A. artemisiifolia is currently being investigated. To our knowledge, this is the first report of a Phoma sp. on A. artemisiifolia in Europe. References: (1) L. Kiss. Biocontrol Sci. Technol. 17:535, 2007. (2) O. Szentiványi et al. Mycol. Res. 109:429, 2005. (3) M. P. Teshler et al. Ambrosia artemisiifolia L., Common Ragweed (Asteraceae) in: Biological Control Programmes in Canada, 1981-2000. CABI, Wallingford, UK, 2002. (4) L. Zhou et al. Mycologia 97:612, 2005.

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The Potential of Rhizoctonia-Like Fungi for the Biological Protection of Cereals against Fungal Pathogens

Plants ◽

10.3390/plants10020349 ◽

2021 ◽

Vol 10 (2) ◽

pp. 349

Author(s):

Dominik Bleša ◽

Pavel Matušinský ◽

Romana Sedmíková ◽

Milan Baláž

Keyword(s):

Biological Control ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Higher Plants ◽

Fusarium Culmorum ◽

Suppressive Effect ◽

Plant Production ◽

Shoot Biomass ◽

Organic Substrates

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are Rhizoctonia-like (Rh-like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses. Various benefits of endophytic associations were proved, including amelioration of devastating effects of pathogens such as Fusarium culmorum. The advantage of Rh-like endophytes over strictly biotrophic mycorrhizal organisms is the possibility of their cultivation on organic substrates, which makes their use more suitable for production. We focused on abilities of five Rh-like fungi isolated from orchid mycorrhizas, endophytic fungi Serendipita indica, Microdochium bolleyi and pathogenic Ceratobasidium cereale to inhibit the growth of pathogenic F. culmorum or Pyrenophora teres in vitro. We also analysed their suppressive effect on wheat infection by F. culmorum in a growth chamber, as well as an effect on barley under field conditions. Some of the Rh-like fungi affected the growth of plant pathogens in vitro, then the interaction with plants was tested. Beneficial effect was especially noted in the pot experiments, where wheat plants were negatively influenced by F. culmorum. Inoculation with S. indica caused higher dry shoot biomass in comparison to plants treated with fungicide. Prospective for future work are the effects of these endophytes on plant signalling pathways, factors affecting the level of colonization and surviving of infectious particles.

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Black Choke Disease Caused by an Ephelis sp. on Purple Fountain Grass in Maryland

Plant Disease ◽

10.1094/pd-90-0112a ◽

2006 ◽

Vol 90 (1) ◽

pp. 112-112

Author(s):

E. Lewis Roberts ◽

J. F. White

Keyword(s):

United States ◽

North America ◽

The United States ◽

Maximum Parsimony Analysis ◽

Bootstrap Support ◽

Herbarium Specimens ◽

Dense Layer ◽

Causal Organism ◽

Plant Nursery ◽

Choke Disease

Purple fountain grass (Pennisetum alopecuroides) is indigenous to Asia, prized for its foxtail-like purple flowers, and widely used as an ornamental. During October 1999, black choke disease was found on P. alopecuroides cv. Hameln (L.) Spreng at a plant nursery in Maryland. Disease symptoms include mummification of inflorescences by black conidial stromata, distorted leaf tissue, and a dense layer of white epiphytic mycelium on the adaxial leaves and culms. Stromata were initially white but became black with age. Microscopic analysis of the isolated fungus indicated that the causal organism was an Ephelis sp., American Type Culture Collection No. MYA-3317. The ephelidial conidia developed in sporodochia on stromata and were hyaline, filiform to acicular, and 18 to 21 × 1 μm. Cultures on potato dextrose agar were off-white and 50 mm in diameter after 14 days at 23°C. Analysis of herbarium specimens of several Balansia spp. revealed that the Ephelis sp. isolate bears morphological resemblance to Asian and not American Balansieae. In fact, the infection observed on Pennisetum sp. forms similarly to Ephelis sp. infection on Oryza sativa L. (Asian) that also results in development of stromata on panicles and a mycelial network enclosing the panicles, preventing maturation and expansion. On both plants, the infected inflorescence becomes black with age and appears mummified as pseudosclerotia form. Furthermore, flag leaves and tillers of both plants appear slightly distorted and silver due to the epibiotic mycelia. The causal agent of black choke disease on rice is Ephelis oryzae Syd. (teleomorph = Balansia oryzae-sativae Hashioka). The mature stroma of E. oryzae forms on the inflorescence and is embedded with a layer of ovate perithecia. Immature stromata bear conidiomata that are cupulate to cushion shaped and black, producing hyaline, branched conidiophores that terminate in phialides. Conidia are ephelidial, filiform to acicular, hyaline, and 18 to 22 × 1.5 μm (2). To determine the phylogenetic relationship between other balansioid fungi and the Ephelis sp. isolate, the nuclear ribosomal internal transcribed spacer (ITS1) region was amplified with primers ITS4 and ITS5 (3). Maximum parsimony analysis of the ITS1 sequences showed that the Ephelis sp. infecting P. alopecuroides cv. Hameln grouped (100% bootstrap support) in a clade with Ephelis oryzae, Balansia sclerotica, Balansia andropogonis, and Balansia sp.; all endemic to Asia and tightly groups with the Asian rice pathogen Ephelis oryzae (100% bootstrap support). Further phylogenetic analysis using topological constraints indicated that Ephelis sp. is not appropriately grouped with American balansioid species. Since P. alopecuroides is often imported to North America from Asia (1), it is likely that Ephelis sp. on P. alopecuroides is endemic to Asia and perhaps was transported along with its host to North America. The disease ontogeny, morphology, and sequence similarities between the Ephelis sp. isolated from Pennisetum sp. and E. oryzae suggests that these fungi are evolutionarily close, sibling species, or conspecific. To our knowledge, this is the first report of choke disease on P. alopecuroides in the United States. References: (1) A. S. Hitchcock. Manual of the Grasses of the United States. A. Chase, ed. U.S. Government Print Office, Washington DC, 1951 (2) F. N. Lee and P. S. Gunnell. Udbatta. Page 29 in: Compendium of Rice Diseases. R. K. Webster and P. S. Gunnell, eds. The American Phytopathological Society, St. Paul. MN, 1992. (3) J. F. White Jr. et al. Mycologia 89:408, 1997.

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Knotweed Management Strategies in North America with the Advent of Widespread Hybrid Bohemian Knotweed, Regional Differences, and the Potential for Biocontrol Via the Psyllid Aphalara itadori Shinji

Invasive Plant Science and Management ◽

10.1614/ipsm-d-15-00047.1 ◽

2016 ◽

Vol 9 (1) ◽

pp. 60-70 ◽

Cited By ~ 10

Author(s):

David R. Clements ◽

Todd Larsen ◽

Jennifer Grenz

Keyword(s):

Biological Control ◽

Invasive Species ◽

Genetic Variation ◽

North America ◽

North American ◽

Regional Differences ◽

The United States ◽

The North ◽

Variable Nature ◽

Available Resources

AbstractInvasive species with distributions that encompass much of the North American environment often demand a range of management approaches, for several key reasons. Firstly, the North American environment includes a large number of highly variable habitats in terms of climatic, edaphic, and landscape features. Secondly, these regional habitat differences are accentuated by jurisdictions within Canada and the United States, whereby approaches and available resources differ at local, regional, and national scales. Another important consideration is whether an invasive species or complex also possesses genetic variation. All three of these factors render the knotweed complex in North America a highly variable target for management. In this paper we review existing knowledge of the variable nature of knotweed species (Fallopia japonica (Houtt.) Ronse Decr., Fallopia sachalinensis (F. Schmidt ex Maxim) Ronse Decr., and Fallopia × bohemica, (Chrtek and Chrtková) J. P. Bailey in North America, and evaluate how herbicidal, mechanical and biological control measures must account for this genetic variation, as well as accounting for regional differences and the potential northward expansion of knotweed under climate change. The imminent release of the psyllid, Aphalara itadori Shinji as a biological control agent in North America must also navigate regional and genetic differences. Prior European experience dealing with the three knotweed species should prove useful, but additional research is needed to meet the emerging challenge posed by F. × bohemica in North America, including the possibility of glyphosate resistance. Managers also face challenges associated with posttreatment restoration measures. Furthermore, disparities in resources available to address knotweed management across the continent need to be addressed to contain the rapid spread of this highly persistent and adaptable species. Linking practitioners dealing with knotweed “on the ground” with academic research is a crucial step in the process of marshalling all available resources to reduce the rapidly spreading populations of knotweed.

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Nicholas Said

10.1093/acrefore/9780190277734.013.966 ◽

2021 ◽

Author(s):

Mohammed Bashir Salau

Keyword(s):

United States ◽

North America ◽

Middle East ◽

19Th Century ◽

North Africa ◽

The United States ◽

Primary Sources ◽

Sahara Desert ◽

Insight Into

The two versions of the autobiography that Nicholas Said published offer insight into 19th-century conditions in five continents as well as insight into life as a child, slave, manservant, and teacher. As a child in the 1830s, Said was enslaved in Borno, marched across the Sahara Desert, and passed from hand to hand in North Africa and the Middle East. After serving as a slave in various societies, Said was freed by a Russian aristocrat in the late 1850s after accompanying the aristocrat in question to various parts of Europe. In the 1850s, Said also traveled as a manservant for a European traveler to South and North America. Ultimately he settled in the United States, where he authored two versions of his autobiography, served as a teacher and soldier, got married, and disappeared from sight. This article compares the two versions of the autobiography that Said published, provides an overview of Said’s life, charts the development of scholarly works on Said, and draws attention to the primary sources related to the study of Said and his autobiography.

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Distribution of Urophora affinis and U. quadrifasciata, Two Flies Introduced for Biological Control of Spotted Knapweed (Centaurea maculosa) in Montana

Weed Science ◽

10.1017/s0043174500078942 ◽

1987 ◽

Vol 35 (2) ◽

pp. 145-148 ◽

Cited By ~ 8

Author(s):

Jim M. Story ◽

Robert M. Nowierski ◽

Keith W. Boggs

Keyword(s):

United States ◽

Biological Control ◽

North America ◽

Positive Relationship ◽

The United States ◽

Centaurea Maculosa ◽

Spotted Knapweed ◽

Seed Head ◽

Strong Positive Relationship ◽

Southeasterly Direction

A survey was conducted at 88 sites in Montana in 1984 and 1985 to determine the distribution of Urophora affinis Frauenfeld and U. quadrifasciata (Meigen), two seed head flies released on spotted knapweed (Centaurea maculosa Lam. # CENMA) in North America. U. affinis, released in Montana during 1973 to 1977, was found at 40 of the 88 sites. The fly was concentrated within a short radius (about 5 to 8 km) of release sites, even at sites having well-established populations. U. quadrifasciata, released in British Columbia in 1972, but not in the United States, was found at 84 sites. The data suggest that the fly entered the state in the northwest corner and dispersed in a southeasterly direction. There was a strong positive relationship between mean number of galls per seed head and percent infestation for both fly species.

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The potential for the use of herbarium specimens to determine the host plants of Ceutorhynchus (Coleoptera: Curculionidae)

The Canadian Entomologist ◽

10.4039/tce.2015.82 ◽

2015 ◽

Vol 148 (4) ◽

pp. 493-498 ◽

Cited By ~ 1

Author(s):

David R. Gillespie ◽

Beth I. Gillespie

Keyword(s):

Biological Control ◽

North America ◽

Host Plant ◽

Host Plants ◽

Herbarium Specimens ◽

Plant Associations ◽

Control Programmes ◽

Herbarium Collections ◽

Developing Knowledge

AbstractThe host plants of native Ceutorhynchus Germar (Coleoptera: Curculionidae) species are poorly known in North America, and knowledge of these is essential for biological control programmes involving this genus of weevils. We hypothesised that weevil larva emergence holes on plant specimens in herbarium collections might reveal potential plant-insect associations, and help locate populations of hosts for non-target testing. We examined 1114 plant specimens in 16 genera and 60 species of Brassicaceae and found 70 specimens among 30 species that showed evidence of feeding injury and exit holes typical of Ceutorhynchus. We used this information to locate populations of two species of Ceutorhynchus. Herbarium collections may be useful tools for developing knowledge of host plant associations for species of Ceutorhynchus.

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Principles of Biological Weed Control

HortScience ◽

10.21273/hortsci.30.4.750d ◽

1995 ◽

Vol 30 (4) ◽

pp. 750D-750

Author(s):

Susan M. Boyetchko

Keyword(s):

Biological Control ◽

Weed Management ◽

Fungal Pathogens ◽

The United States ◽

Reproductive Capacity ◽

Biological Weed Control ◽

Weed Biocontrol ◽

Weed Growth ◽

Inundative Biological Control ◽

High Concentrations

Weeds continue to have a tremendous impact on crop yield losses in Canada and the United States, despite efforts to control them with chemicals. Biological control offers an additional means for reducing weed populations while reducing the reliance of the agri-food industry on chemical pesticides. Effective biological strategies that are compatible with good soil conservation practices would benefit farmers while maintaining environmental quality and a sustained production for the future. Inundative biological control of weeds with microbial agents involves the mass production and application of high concentrations of a plant pathogen to a target weed. Historically, biocontrol agents used on weeds have been foliar fungal pathogens. More recently, the soil has become a source for microorganisms, such as rhizobacteria, for development as biological control agents. Several naturally occurring rhizobacteria have weed suppressive properties, where growth and development of weeds such as downy brome, wild oats, leafy spurge, and green foxtail are significantly inhibited. Although the focus in weed biocontrol has been on the eradication of weeds, rhizobacteria may be used to improve seedling establishment of the crop by reducing the weed competition. This can be achieved through a reduction in weed growth, vigor, and reproductive capacity and improvement in the ability of the crop to compete with the weed. Current research in weed biocontrol with microorganisms and its application to weed management systems will be discussed.

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Differential Susceptibility of Bagrada hilaris (Hemiptera: Pentatomidae) to Different Species of Fungal Pathogens

Journal of Economic Entomology ◽

10.1093/jee/toz246 ◽

2019 ◽

Author(s):

Anahi A Barrera-López ◽

Ariel W Guzmán-Franco ◽

Materesa Santillán-Galicia ◽

Fernando Tamayo-Mejía ◽

Rafael Bujanos-Muñiz ◽

...

Keyword(s):

Biological Control ◽

Fungal Pathogens ◽

Microbial Control ◽

Differential Susceptibility ◽

Field Studies ◽

The United States ◽

Fungal Species ◽

Biological Control Agents ◽

Percent Mortality ◽

Microbial Agents

Abstract Bagrada hilaris Burmeister (Hemiptera: Pentatomidae) is a pest of Palearctic origin. Its presence in the United States was first reported in 2008 and in Mexico in 2014; it affects brassica crops. There are practically no reports of natural enemies of B. hilaris in America. Entomopathogenic fungi are strong candidates for microbial control of this pest. Evaluating the susceptibility of this pest to fungi that are native to the region where they will be used is a sensible first step to finding candidate biological control agents. The aim of our research was to select potential microbial agents to control B. hilaris. Eleven isolates of Beauveria bassiana, Beauveria pseudobassiana, Metarhizium anisopliae, and Isaria fumosorosea were evaluated to determine the susceptibility of B. hilaris. Isolates of B. bassiana caused the highest mortality due to infection (100%) compared with the other isolates. The I. fumosorosea isolate caused the lowest percent mortality (56%). The two B. bassiana isolates Bb88 and AP3 were more virulent than M. anisopliae isolate Ma129. The sex of the insect had no effect on infection levels achieved by B. bassiana isolates Bb88 and AP3. The results of our study contribute valuable information for the development of fungal species with potential to manage B. hilaris populations. Field studies are the next step in order to develop these isolates as biological control agents of B. hilaris.

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ACHILLEA MILLEFOLIUM COMPLEX IN CANADA AND PORTIONS OF THE UNITED STATES

Canadian Journal of Botany ◽

10.1139/b59-007 ◽

1959 ◽

Vol 37 (1) ◽

pp. 73-79 ◽

Cited By ~ 8

Author(s):

Gerald A. Mulligan ◽

I. John Bassett

Keyword(s):

North America ◽

Prince Edward Island ◽

Native Species ◽

Pollen Grains ◽

The United States ◽

Achillea Millefolium ◽

Herbarium Specimens ◽

Male Sterile ◽

Eastern Canada ◽

The Pacific

The chromosome numbers of plants of the Achillea millefolium complex from 27 locations in North America are reported. The levels of polyploidy found are correlated with diameters of the pollen grains. Measurements of pollen grains from more than 300 herbarium specimens are used as an indication of the occurrence of tetraploid and hexaploid species of Achillea in Canada. The results of some crossing experiments are also reported. It is concluded that the common Achillea of North America is tetraploid and is the native A. lanulosa Nutt. It extends from the Pacific to the Atlantic coasts, as far south as California in the west and Pennsylvania in the east, and to northern Canada and Alaska. Another native species, hexaploid Achillea borealis Bong., extends along the Pacific coast from southern California to the Aleutian Islands and along the northern shorelines of Alaska and Canada. A Eurasiatic hexaploid, A. millefolium L. s. str., has been sparingly introduced into Newfoundland, Prince Edward Island, Nova Scotia, and perhaps elsewhere along the Atlantic seaboard. In eastern Canada a male-sterile purple-flowered hexaploid also occurs. This hexaploid escapes from cultivation and forms localized patches. It undoubtedly has been selected from the Eurasiatic A. millefolium L. s str.

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