Influence of host and pathogen variables on the efficacy of Phoma herbarum, a potential biological control agent of Taraxacum officinale

2002 ◽  
Vol 80 (4) ◽  
pp. 425-429 ◽  
Author(s):  
Silke Neumann ◽  
Greg J Boland
Keyword(s):  
Weed Control ◽  
Biological Control Agent ◽  
Severe Disease ◽  
Taraxacum Officinale ◽  
Control Agent ◽  
Biological Weed Control ◽  
Optimal Conditions ◽  
Potato Dextrose Broth ◽  
Phoma Herbarum ◽  
Important Host

Phoma herbarum Westendorp has been identified as a potential biological weed control agent (BWCA) for Taraxacum officinale Weber in turf. However, host and pathogen variables that influence the efficacy of this BWCA need to be identified to provide more optimal conditions for production and efficacy. In controlled-environment studies, 4-week-old T. officinale plants were significantly more susceptible to P. herbarum than were plants that were 6 and 8 weeks old, nonflowering but mature, budding, or flowering. Mycelial suspensions incited significantly more severe disease than conidia, and 5-day-old mycelial shake cultures incited significantly higher disease than 3-, 7-, 9-, 11-, or 13-day-old cultures. A concentration of 10 to 20% of mycelial fragments in potato dextrose broth (v/v) incited higher disease severity than 0, 40, 60, or 100%. These experiments identified several important host and pathogen variables that influence the efficacy of P. herbarum on T. officinale and established more optimal conditions for production and efficacy of this BWCA.Key words: biological weed control, bioherbicide, mycoherbicide, Taraxacum officinale, dandelion, Phoma herbarum.

Influence of Selected Adjuvants on Disease Severity byPhoma herbarumon Dandelion (Taraxacum officinale)

1999 ◽  
Vol 13 (4) ◽  
pp. 675-679 ◽  
Author(s):  
Silke Neumann ◽  
Greg J. Boland
Keyword(s):  
Disease Severity ◽  
Triticum Durum ◽  
Guar Gum ◽  
Biological Control Agent ◽  
Taraxacum Officinale ◽  
Control Agent ◽  
Controlled Environment ◽  
Cyamopsis Tetragonoloba ◽  
Phoma Herbarum ◽  
Environment Study

Phoma herbarumwas evaluated as a potential biological control agent for dandelion (Taraxacum officinale) in turf. A preliminary controlled environment study identified selected adjuvants that enhanced disease severity byP. herbarum.Subsequently, these adjuvants were evaluated for disease enhancement under field conditions. Adjuvants evaluated included gluten flour, liposome, guar gum from ground guar (Cyamopsis tetragonoloba), durum (Triticum durum), and pectin. Regression analysis revealed a significant (P= 0.05) increase in disease severity byP. herbarumwhen formulated with gluten Hour, guar gum, or durum semolina compared to treatment with 20% mycelium in potato (Solanum tuberosum) dextrose broth (PDB) alone. No phytotoxicity to dandelion was observed among the adjuvant controls.

Oviposition Site Preferences ofGalerucella calmariensisandG. pusilla, Biological Control Agents of Purple Loosestrife (Lythrum salicaria)

1997 ◽  
Vol 11 (4) ◽  
pp. 824-827 ◽  
Author(s):  
Cory John Lindgren
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Control Agent ◽  
Lythrum Salicaria ◽  
Oviposition Site ◽  
Purple Loosestrife ◽  
Biological Weed Control ◽  
Flower Buds ◽  
Egg Masses ◽  
Site Preferences

Oviposition site preferences forGalerucella calmariensisandG. pusilla, biological weed control agents against purple loosestrife, were examined in 1994 and 1995. The leaves, stems, axils, and flower buds (G. pusilladid not oviposit on flower buds) were found to be the preferred oviposition sites. Oviposited egg masses may be used as a parameter within a biological control monitoring plan, providing information onGalerucellaestablishment and/or presence, estimating future population size, and providing biological control agent dispersal information. Monitoring for egg masses should concentrate on host plant leaves, where over 56% of all egg masses were oviposited.

HOST SPECIFICITY OF LIRIOMYZA SONCHI HENDEL (DIPTERA: AGROMYZIDAE), A POTENTIAL BIOLOGICAL AGENT FOR THE CONTROL OF WEEDY SOW-THISTLES, SONCHUS SPP., IN CANADA

1988 ◽  
Vol 120 (6) ◽  
pp. 593-600 ◽  
Author(s):  
Diether P. Peschken ◽  
Jo-Anne L. Derby
Keyword(s):  
Host Specificity ◽  
Recent Literature ◽  
Biological Control Agent ◽  
Taraxacum Officinale ◽  
Control Agent ◽  
Economic Importance ◽  
Choice Test ◽  
Choice Tests ◽  
Sonchus Arvensis ◽  
Helichrysum Bracteatum

AbstractLiriomyza sonchi Hendel was screened for its host specificity as a potential biological control agent against sow-thistles (Sonchus spp.). Recent literature indicated that L. sonchi is recorded frequently from Sonchus spp., but also from Arnoseris minima Schweigger and Koerte and Reichardia arabicum Hochstetter and Steudel. A total of 78 plant species were tested, including 37 species in the Cichorieae (Compositae). In no-choice tests, feeding punctures were observed on species in the closely related genera Aetheorrhiza, Crepis, Lactuca, and Taraxacum, and such distantly related species as Helichrysum bracteatum Andrews var. monstrosum Hortorum (Inuleae tribe, Compositae) and Pisum sativum L. (Leguminosae). From 0.04 to 0.67 adults per female were produced on Aetheorrhiza bulbosa (L.), Crepis dioscordis L., C. rubra L., Leontodon hispidus L., and Taraxacum officinale Weber as compared with about 23 per female on its host, Sonchus arvensis L. No species in these genera other than Sonchus are reported as hosts in the field in Europe and they are therefore considered to be cage-induced hosts. Because of its economic importance, 10 cultivars of lettuce, Lactuca sativa L., were exposed to a total of 837 females in no-choice tests. One puparium and one adult (0.006 per female) were produced. In one replicated choice test with 150 females, no mines were produced on lettuce. It is concluded that the field host range of L. sonchi is restricted to Sonchus spp.

Controlling Weeds with Phytopathogenic Bacteria

1996 ◽  
Vol 10 (3) ◽  
pp. 621-624 ◽  
Author(s):  
David R. Johnson ◽  
Donald L. Wyse ◽  
Keith J. Jones
Keyword(s):  
Weed Control ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Severe Disease ◽  
Jerusalem Artichoke ◽  
Field Conditions ◽  
Biological Weed Control ◽  
Spray Application ◽  
Phytopathogenic Bacteria ◽  
Annual Bluegrass

Until recently, phytopathogenic bacteria have not been considered potential biological weed control candidates because they lack the ability to penetrate intact plants. This deficiency can be overcome by providing entry wounds or using surfactants. Spray application ofPseudomonas syringaepv.tagetis(5 × 108cells/ml) in aqueous buffer with a surfactant produced severe disease in Canada thistle, common ragweed, Jerusalem artichoke, sunflower, and certain other members of the Compositae under field conditions. Spray application of the bacterium without surfactant was ineffective on all reported hosts.Xanthomonas campestrispv.poannuacontrolled annual bluegrass in bermudagrass golf greens when applied by spray during mowing. The bacterium entered through mowing injuries, causing lethal, systemic wilt. Application of the bacterium to annual bluegrass in the absence of fresh mowing injuries failed to produce symptoms. Under field conditions, this previously unknown pathovar's host range was limited to a single subspecies of annual bluegrass, but inundative application to freshly mowed turf resulted in infection of diverse annual bluegrass biotypes. In field trials, six monthly applications resulted in greater than 70% control. The preceding examples are among the first attempts to use foliar phytopathogenic bacteria for biological weed control. Efficacy of these bacterial bioherbicides and of future biocontrol strategies employing bacteria is dependent on facilitated host penetration.

Population Dynamics of Broadleaf Weeds in Turfgrass as Influenced by Chemical and Biological Control Methods

Weed Science ◽  
2007 ◽  
Vol 55 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Mohammed H. Abu-Dieyeh ◽  
Alan K. Watson
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Weed Control ◽  
Seed Bank ◽  
Biological Control Agent ◽  
Control Agent ◽  
Weed Species ◽  
Early Autumn ◽  
Herbicide Treatment ◽  
Broadleaf Species

A 3-yr field study was conducted to determine the effect of a biological control agent,Sclerotinia minorJagger, and a common herbicide, Killex, on the population dynamics of dandelion and other broadleaf species and on the dandelion seed bank. Treatments were applied as one spring, one early autumn, or a spring plus an early autumn treatment per year. The response of the dandelion population to a spring herbicide treatment was similar to two applications per year (spring and early autumn). Significantly less dandelion control occurred after the first early autumn application of the herbicide. Two weeks after application, spring or early autumn treatments withS. minorwere equally effective in suppressing dandelions. In the second year of the two applications per year ofS. minortreatment, weed control was equivalent to the herbicide. By the third year of the one spring application ofS. minor, weed control was equivalent to the herbicide. Generally over the study period, the early autumn application ofS. minorwas less effective than the spring or the spring and early autumn applications. TheS. minortreatments significantly reduced the dandelion seed bank, and this effect was not significantly different from the Killex herbicide treatment. The rate, frequency, and seasonal timing of application had no effect on the dandelion seed-bank size, but terminating the application would gradually replenish the seed bank. Populations of white clover, broadleaf plantain, birdsfoot trefoil, and common ragweed were similarly suppressed by either theS. minoror the herbicide treatments. Yellow woodsorrel significantly increased after 1 yr of herbicide treatment compared with theS. minorand untreated control treatments, indicating a possible weed species shift. Turf quality was improved because of the herbicide andS. minortreatments, but grass injury and smooth crabgrass invasion were recorded in 17% of herbicide-treated plots.

scholarly journals Occurrence of Dactylaria higginsii on Purple Nutsedge in Florida

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 588-588 ◽  
Author(s):  
J. B. Kadir ◽  
R. Charudattan
Keyword(s):  
Biological Control Agent ◽  
Severe Disease ◽  
First Record ◽  
The United States ◽  
Control Agent ◽  
Cyperus Rotundus ◽  
Commonwealth Mycological Institute ◽  
Purple Nutsedge ◽  
Small Water ◽  
Yellow Nutsedge

In September 1994, a population of severely diseased purple nutsedge (Cyperus rotundus L.) was found in Gainesville, FL. The symptoms were characterized by necrotic leaf spots, blotches, and foliar blighting. A fungal isolate was consistently recovered from symptomatic leaves and grown in pure culture. Based on the characteristics of conidia (28.6 × 6.6 μm) and conidiophores (45.2 × 7.0 μm at the broadest base), the fungus was identified as Dactylaria higginsii (Luttrell) M.B. Ellis. This fungus was first described as Piricularia [sic] higginsii from Georgia (4) and later redescribed as D. higginsii (2). A Pyricularia sp. and P. grisea (Cooke) Sacc. have been recorded on C. alternifolius L., C. papyrus L., and other Cyperus spp. from Florida, but species of Pyricularia or Dactylaria have not been reported from this state on purple nutsedge (1). Proof of pathogenicity (Koch's postulates) was established in repeated trials in a greenhouse; the disease symptoms were reproduced, and the fungus was reisolated from inoculated plants and confirmed to be the same organism used for inoculations. Four- to six-leaf-stage purple nutsedge and yellow nutsedge (C. esculentus L.) plants were sprayed with a suspension of 1 × 106 conidia per ml amended with 0.02% Silwet L-77 (vol/vol). Control plants were sprayed with 0.02% Silwet L-77 only. Small, water-soaked lesions developed 4 days after inoculation. The lesions coalesced into larger necrotic blotches with grayish centers 8 days after inoculation. Most of the inoculated foliage was blighted within 15 days after inoculation. The disease did not kill nutsedge bulbs or tubers, but reduced shoot and tuber yields. None of the control plants developed any symptoms. The ability of D. higginsii to cause severe disease and reduce the yields of vegetative organs indicates that it has potential as a biological control agent for purple nutsedge and yellow nutsedge, two of the world's worst weeds. This is the first record of occurrence of D. higginsii outside of its original distribution in Georgia (3). References: (1) S. A. Alfieri, Jr., et al. 1994. Diseases and Disorders of Plants in Florida. Bull. No. 14. Division of Plant Industry, Gainesville, FL. (2) M. B. Ellis. 1976. More Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England. (3) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN. (4) E. S. Luttrell. Mycologia 46:810, 1954.

scholarly journals NOVEL ROLE OF 6-N-PENTYL-6H-PYRAN-2-ONE PRODUCED BY Trichoderma harzianum IN HYDROPONIC SYSTEM

2019 ◽  
pp. 1-15
Author(s):  
WALID NOSIR ◽  
MOSTAFA RATEB
Keyword(s):  
Secondary Metabolites ◽  
Biological Control Agent ◽  
Interaction Mechanism ◽  
Control Agent ◽  
Potato Dextrose Broth ◽  
Expression Studies ◽  
Trichoderma Sp ◽  
Nmr Techniques ◽  
Gene Expression Studies ◽  
Layer Chromatography

Secondary metabolites play a pivotal role in the antagonistic activities of some biocontrol species of Trichoderma sp. T. harzianum used previously as biological control agent against different pathogens. In this work, the effect of F. oxysporum f. sp. gladioli on the major secondary metabolites secreted by biocontrol strain of T. harzianum in Potato Dextrose Broth (PDB) cultures were investigated and quantified; followed by investigating the effect of the previous microorganisms on T. harzianumsecondary metabolites secreted in Gladiolus grandiflorus corms tissues under controlled conditions. Thin Layer Chromatography (TLC), Liquid chromatography Mass spectroscopy (LC/MS), and Nuclear Magnetic Resonance (NMR) techniques were used in this study to determine the major secondary metabolites. This is the first report recording the isolation, characterization and quantification of 6-n-pentyl-6H-pyran-2-one (6PP) and harzianic acid (HA) from the treated corms with T. harzianum. The secreted amounts from both metabolites were increased in the pre treated corms with T. harzianum followed by infection with F. oxysporum f. sp. gladioli. Results provided better understandings of the interaction mechanism between T. harzianum, F. oxysporum f. sp. gladioli which could be used in the future in different gene expression studies and will help in using them as bio fertilizers in biocontrol field.

Host range of Alternaria alternata f.sp. sphenocleae causing leaf blight of Sphenoclea zeylanica

1999 ◽  
Vol 77 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Rhomela F Masangkay ◽  
Maxima O Mabbayad ◽  
Timothy C Paulitz ◽  
Alan K Watson
Keyword(s):  
Plant Species ◽  
Alternaria Alternata ◽  
Biological Control Agent ◽  
Oryza Sativa L ◽  
Control Agent ◽  
Biological Weed Control ◽  
Psophocarpus Tetragonolobus ◽  
Raphanus Sativus L ◽  
Glycine Max L ◽  
Moderately Resistant

Forty-eight plant species in 40 genera representing 20 families were screened for susceptibility to Alternaria alternata (Fr.) Keissler f.sp. sphenocleae, a candidate biological control agent for Sphenoclea zeylanica Gaertner (gooseweed). Gooseweed was the only species susceptible to A. alternata f.sp. sphenocleae when plants were treated with 3.5 × 105 conidia/mL (approximately 107 conidia/m2) in the presence or absence of supplemental dew. All inoculated gooseweed plants were killed when subjected to a 14- to 15-h dew. Lactuca sativa L. (lettuce), Glycine max (L.) Merrill (soybean), Phaesolus vulgaris L. (common bean), Psophocarpus tetragonolobus (L.) DC. (winged bean), Vigna radiata (L.) R. Wilcz. (mung bean), Vigna unguiculata (L.) Walp. (string bean), Musa sapientum L. (banana), and some Oryza sativa L. (rice) cultivars showed highly resistant reactions. Brassica oleracea L. (cabbage), Raphanus sativus L. (radish), and Abelmoschus esculentus (L.) Moench (okra) showed highly resistant to moderately resistant reactions while Gossypium hirsutum L. (cotton) showed moderately resistant to moderately susceptible reactions. Symptoms on cotton were restricted to the cotyledons. Sporulation, however, was observed only on detached excised gooseweed leaves, and no sporulation occurred on any of the other plant species evaluated. Gooseweed was the only compatible host plant of A. alternata f.sp. sphenocleae found in these studies.Key words: Alternaria alternata f.sp. sphenocleae, biological weed control, host specificity, gooseweed, Sphenoclea zeylanica.

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