DOCSLIB.ORG

Efficacy of Various Biological Control Agents and Biorationals Against

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Efficacy of Various Biological Control Agents and Biorationals Against that two products based on two vascular system exposed. Although P. Efficacy of different species of Streptomyces, ultimum var. ultimum seldom pro- Various Mycostop and Actino-Iron, were as duces zoospores, the motile propagules effective as metalaxyl at reducing the produced by oomycetes such as symptoms associated with pythium Pythium, the fungus has been isolated Biological root rot when artificially inoculated with Pythium ultimum var. ultimum from reservoirs where the fertilizer so- Control Agents compared to the control plants. Many lutions are stored (J.A. Gracia-Garza, roots remained functional throughout unpublished) and can easily be dis- and Biorationals the duration of the experiments and seminated throughout a greenhouse the overall appearance and number of operation that uses a recirculating subir- against Pythium bracts of commercial quality of the rigation system. Root Rot in plants were similar for the three Several chemical products are rec- treatments mentioned above. In an ommended for use against this patho- Poinsettia additional experiment, Mycostop was gen. In Ontario, metalaxyl (Subdue, tested in combination with a single Syngenta Crop Protection Canada Inc., application of metalaxyl either at 3, 7, or 11 weeks after transplanting. Guelph, Ont., Canada) and fosetyl- J.A. Gracia-Garza,1,5 Plants inoculated with P. ultimum aluminum (Aliette, Rhone-Poulenc var. ultimum and treated with Canada, Mississauga, Ont., Canada) 2 3 M. Little, W. Brown, metalaxyl either on week 3 or 7 after are two chemicals registered for the 4 1 transplanting in combination with control of root rot caused by Pythium T.J. Blom, K. Schneider, two applications of Mycostop, had in ornamental crops. However, recent W. Allen,1 and J. Potter1 greater fresh root weight than those studies have indicated that some iso- only treated with metalaxyl at week 11 lates of Pythium are becoming less or the chemical control (three applica- sensitive to metalaxyl (Daughtrey, tions of metalaxyl). However, there 1998). Thus, alternative strategies must ADDITIONAL INDEX WORDS. Euphorbia was no significant difference in the pulcherrima, Gliocladium, metalaxyl, number of bracts or the bract diameter be found before resistance to these Pseudomonas, Streptomyces, Tricho- between plants treated with metalaxyl pesticides is fully developed. Many dif- derma at weeks 3 or 7 followed by Mycostop ferent organisms, including actino- and those plants treated with the mycetes, have been reported as poten- SUMMARY. Pythium root rot (Pythium fungicide alone. A reduction in the tial biocontrol agents (BCA) against spp.) is a common disease of green- amount of fungicide used to control Pythium (Liang et al., 1996; house-grown poinsettias (Euphorbia pythium root rot can be achieved when Mahadevan and Crawford, 1997; pulcherrima) that can cause serious used in combination with a biocontrol McCullagh et al., 1996; Rankin and plant loss or reduction in plant agent without compromising the Paulitz, 1994). Streptomyces are aero- quality. Application of effective health of poinsettias. bic, gram-positive actinomycetes with chemical fungicides to poinsettia plants has reduced losses due to reported activity against several plant Pythium; however, development of pathogens, including Pythium resistance to these fungicides is a oot rots caused by Pythium (Mahadevan and Crawford, 1997). legitimate concern, as well as the species are of great con- The mechanisms by which Streptomy- environmental implications of using R cern to growers in the floricul- ces are able to reduce losses due to chemical pesticides. In this study, a tural industry particularly since the soilborne pathogens include competi- group of products of biological origin adoption of new irrigation technolo- tion for nutrients, and production of and known biocontrol agents were gies that prevent the run off of chemi- antimicrobial products and lytic en- evaluated for their efficacy to control cals into the environment. At present, zymes (Kortemaa et al., 1994; pythium root rot of poinsettia. These Mahadevan and Crawford, 1997). The products and organisms were com- 25% to 30% of commercial greenhouses pared to metalaxyl (Ridomil), a in the Niagara region of southern objectives of the study presented here fungicide commonly used to reduce Ontario, Canada, are using recirculat- were 1) to evaluate several commer- losses to Pythium. The results showed ing irrigation systems. In addition, cially available products of biological growers of potted floricultural crops origin for their ability to reduce or are replacing the traditional overhead eliminate root rot in poinsettia and 2) The support of Flowers Canada (Ontario) Inc., and all (drip) irrigation with subirrigation. to determine if a single application of the companies that provided samples and their repre- sentatives, is appreciated. These changes in irrigation practices the fungicide metalaxyl in combina- 1Agriculture and Agri-Food Canada, Southern Crop have increased the concerns about tion with a strain of Streptomyces Protection and Food Research Centre, 4902 Victoria pathogen contamination of fertilizer griseoviridis, will provide satisfactory Ave. N., P.O. Box 6000, Vineland Station, Ont., solutions and the reservoirs where these control of P. ultimum. Canada L0R 2E0. solutions are maintained. Poinsettia 2Brock University, St. Catharines, Ont., Canada L2S Materials and methods 3A1. plants are often infected by the patho- PLANT MATERIAL, PATHOGENS AND 3Ontario Ministry of Agriculture and Food. gen Pythium ultimum var. ultimum. Symptoms of plants infected with this SCREENED BCAS, AND BIORATIONALS. 4University of Guelph, Department of Plant Agricul- ture, 4890 Victoria Ave. N., Vineland Station, Ont., pathogen are stunting, chlorosis, and a Cuttings from stock ‘Freedom’ poin- Canada L0R 2E0. general wilting. Infected roots are settia plants, were collected and rooted 5Corresponding author; email Gracia- brown with rotted tips and the cortex in Oasis (Smithers-Oasis, Kent, Ohio) [email protected]. usually sloughs off easily, leaving the for 4 weeks. Rooted cuttings were G January–March 2003 13(1) 149 RR8 149 11/22/02, 2:27 AM RESEARCH REPORTS then transplanted into 10-cm-diam- (Beckman Du 640, Beckman Instru- was inoculated (2 weeks after trans- eter (4-inch) plastic pots, using Sun- ments, Inc. Fullerton, Calif.), to ob- planting) with Po20 through shine Mix # 4, (SunGro Horticulture tain a final absorptivity reading of 0.14 subirrigation with an infested fertilizer Inc., Westerville, Ohio), a peat-based (wavelength of 650 µm). At this ab- solution, and the other set served as a soilless medium. sorptivity, the solution was estimated noninoculated control (i.e., Pythium- Plants were treated as follows to contain 6 × 107 cfu/mL (1.8 × 109 free). For those plants receiving a (Table 1): 1) control; 2) Actino-Iron cfu/fl oz). The bacterial solution was drench, each plant received 100 mL (Natural Industries, Inc., Houston, diluted to 106 cfu/mL (3.0 × 107 cfu/ (3.4 fl oz) of the appropriate solution. Texas) containing: Streptomyces lydicus fl oz) before inoculating the plants. Each treatment was placed in a sepa- WYEC 108, 18% to 20% iron, 30% to The strain TMCS 3 was grown on rate trough and each trough was con- 32% fulvic acid blended into the pot- Petri plates containing potato dex- nected to a separate tank. Recirculat- ting medium at 3 g·L–1 (label rate) trose agar (PDA) (Difco Laboratories, ing tanks were filled with a fertilizer before planting; 3) BTM (Earth Corp Detroit, Mich.) for 5 d before harvest- solution containing, in mmol·L–1 (ppm): – Environmental Ltd., Calgary, Alta., ing conidia. Conidia were scraped from 12.25 (760) nitrate (NO3 ), 2.25 (40.5) + Canada) containing several genera of the surface of the plate with a metal rod ammonium (NH4 ), 1.0 (97) – bacteria (Bacillus, Clostridium, after adding 15 mL (0.5 fl oz) of sterile dihydrogen phosphate (H2PO4 ), 3.5 Enterobacter, Pseudomonas, and Rhizo- water. The spore solution was diluted (136.5) potassium (K+), 3.75 (150) cal- bium) in a humic acid solution applied until a 106 cfu/mL concentration was cium (Ca2+), 1.0 (24) magnesium –1 2+ 2– as a monthly drench at 5.5 mL·L obtained. (Mg ), 1.0 (96) sulphate (SO4 ), 0.025 (label rate); 4) Modicell (DeruNed Pythium ultimum var. ultimum (1.4) iron (Fe2+), 0.005 (0.28) manga- BV, Bergschenhoek, The Netherlands) isolate Po20 (Po20) was originally iso- nese (Mn2+), 0.0035 (0.23) zinc (Zn2+), 3– containing enzymes extracted from sev- lated from a diseased poinsettia plant 0.020 (1.2) borate (BO3 ), 0.0008 eral genera of fungi applied as a monthly in the Niagara region. The pathogen (0.05) copper (Cu2+), and 0.0005 –1 2– drench at 1.5 mL·L (label rate); 5) was grown in a V8 liquid medium (0.08) molybdate (MoO4 ). Irriga- Mycostop (Kemira Agro Oy, Helsinki, amended with calcium carbonate tion of all plants was changed to clear –1 Finland) containing S. griseoviridis (CaCO3) [10 g·L (1.34 oz/gal) of water when cyathia began to produce strain K61 applied as a monthly drench V8 juice]. The growing medium was pollen according to commercial prac- at 0.06 g·L–1 (label rate); 6) Pseudomo- similar to that described by Miller tices. Experimental plants were grown nas fluorescens strain 15 (T.C. Paulitz, (1955) without adding agar. The cul- in a greenhouse for 15 weeks with the collection) applied by dipping the Oasis tures were incubated on an orbital following equal day/night tempera- cube in a solution containing 106 cfu/ mechanical shaker (150 rpm) for 10 d ture regimes: 21 °C (70 °F) during mL at transplanting; 7) metalaxyl under constant incandescent light at vegetative growth and flower initia- (Ridomil 240. E.C.; Syngenta Crop 26 °C (79 °F). Cultures were then tion, 19 °C (66 °F) during flower Protection Canada Inc., Guelph, Ont., blended for 30 s to homogenize the development and 17 °C (63 °F) for Canada) applied as a monthly drench sporangia and oospores in the culture.
Load more

Recommended publications
  • Pythium Ultimum Species Complex
    Resolving thePythium ultimum species complex by Quinn Eggertson A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs partial fulfillment of the requirements for the degree of Master of Science in Biology Carleton University Ottawa, Ontario ©2012 Quinn Eggertson Library and Archives Bibliotheque et Canada Archives Canada Published Heritage Direction du 1+1 Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-93569-9 Our file Notre reference ISBN: 978-0-494-93569-9 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distrbute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation.
    [Show full text]
  • Characterization of Resistance in Soybean and Population Diversity Keiddy Esperanza Urrea Romero University of Arkansas, Fayetteville
    University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 7-2015 Pythium: Characterization of Resistance in Soybean and Population Diversity Keiddy Esperanza Urrea Romero University of Arkansas, Fayetteville Follow this and additional works at: http://scholarworks.uark.edu/etd Part of the Agronomy and Crop Sciences Commons, Plant Biology Commons, and the Plant Pathology Commons Recommended Citation Urrea Romero, Keiddy Esperanza, "Pythium: Characterization of Resistance in Soybean and Population Diversity" (2015). Theses and Dissertations. 1272. http://scholarworks.uark.edu/etd/1272 This Dissertation is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected], [email protected]. Pythium: Characterization of Resistance in Soybean and Population Diversity A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science by Keiddy E. Urrea Romero Universidad Nacional de Colombia Agronomic Engineering, 2003 University of Arkansas Master of Science in Plant Pathology, 2010 July 2015 University of Arkansas This dissertation is approved for recommendation to the Graduate Council. ________________________________ Dr. John C. Rupe Dissertation Director ___________________________________ ___________________________________ Dr. Craig S. Rothrock Dr. Pengyin Chen Committee Member Committee Member ___________________________________ ___________________________________ Dr. Burton H. Bluhm Dr. Brad Murphy Committee Member Committee Member Abstract Pythium spp. are an important group of pathogens causing stand losses in Arkansas soybean production. New inoculation methods and advances in molecular techniques allow a better understanding of cultivar resistance and responses of Pythium communities to cultural practices.
    [Show full text]
  • Enhancing the Potentiality of Trichoderma Harzianum Against Pythium Pathogen of Beans Using Chamomile (Matricaria Chamomilla, L.) Flower Extract
    molecules Article Enhancing the Potentiality of Trichoderma harzianum against Pythium Pathogen of Beans Using Chamomile (Matricaria chamomilla, L.) Flower Extract Abeer Abdulkhalek Ghoniem 1, Kamar M. Abd El-Hai 2, Ayman Y. El-khateeb 3, Noha M. Eldadamony 4, Samy F. Mahmoud 5 and Ashraf Elsayed 6,* 1 Microbial Activity Unit, Department of Microbiology, Soils, Water and Environment Research Institute, Agricultural Research Center, Giza 12619, Egypt; [email protected] 2 Department of Leguminous and Forage Crop Diseases, Plant Pathology Research Institute, Agricultural Research Center, Giza 12112, Egypt; [email protected] 3 Department of Agricultural Chemistry, Faculty of Agriculture, Mansoura University, Elgomhouria St., Mansoura 35516, Egypt; [email protected] 4 Seed Pathology Department, Plant Pathology Institute, Agricultural Research Center, Giza 12112, Egypt; [email protected] 5 Department of Biotechnology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; [email protected] 6 Botany Department, Faculty of Science, Mansoura University, Elgomhouria St., Mansoura 35516, Egypt * Correspondence: [email protected] Abstract: Our present study was designed to investigate the role of both Trichoderma harzianum and Citation: Ghoniem, A.A.; Abd chamomile (Matricaria chamomilla L.) flower extract in mutual reaction against growth of Pythium El-Hai, K.M.; El-khateeb, A.Y.; ultimum. In vitro, the activity of chamomile extract was found to reduce the radial growth of Eldadamony, N.M.; Mahmoud, S.F.; Pythium ultimum up to 30% compared to the control. Whereas, the radial growth reduction effect Elsayed, A. Enhancing the of T. harzianum against P. ultimum reached 81.6% after 120 h.
    [Show full text]
  • Two Species of Phytopythium (Pythiaceae, Pythiales) New to China
    Journal of Microbiology & Experimentation Research Article Open Access Two species of Phytopythium (Pythiaceae, Pythiales) new to China Abstract Volume 7 Issue 5 - 2019 Two oomycetes, Phytopythium mercuriale and Pp. sindhum were found in southern China, Jia-Jia Chen,1,2 Hui Feng,1 Xiaobo Zheng1 and they are newly recorded in China. These two species were both isolated from roots of 1Department of Plant Pathology, Nanjing Agricultural University, soybean. Pp. mercuriale is characterized by subglobose sporangia with conspicuous apical China papillae, and occasionally forming oogonia. And Pp. sindhum is identified from other 2College of Landscape Architecture, Jiangsu Vocational College Phytopythium species by its globose to sub-globose sporangia with conspicuous apical of Agriculture and Forestry, China papillae, large and smooth oogonia, monoclinous or diclinous antheridia, and plerotic or nearly plerotic and thick-walled oospores. Illustrations and descriptions of the two new Correspondence: Xiaobo Zheng, Department of Plant records are provided based on the materials from China. Pathology, Nanjing Agricultural University, Nanjing 210095, China, Tel 18362090654, Email Keywords: Cox1, ITS, Oomycota, Phytopythium mercuriale, Phytopythium sindhum Received: August 09, 2019 | Published: September 16, 2019 Abbreviations: BI, bayesian inference; BPP, bayesian posterior in China. The isolation procedure followed the method described by probabilities; BT, bootstrap; CMA, corn meal agar; CI, consistency Benard & Punja.11 Pieces of tissue 5–10mm were cut from the roots, index; Cox1, cytochrome c oxidase subunit 1; GTR, general time washed in tap water and superficially dried on a paper towel, and plated reversible; HI, homoplasy index; ITS, the internal transcribed spacer; on CMA containing rifampicin (50mg/L), phenamacril (5mg/L), MP, maximum parsimony; MPT, maximum parsimonious tree; NJAU, ampicillin (50mg/L), and pentachloronitrobenzene (50mg/L) and the College of Plant Protection, Nanjing Agricultural University; incubated at 25°C for 2–3d.
    [Show full text]
  • Biocontrol of Pythium Aphanidermatum by the Cellulolytic Actinomycetes Streptomyces Rubrolavendulae S4
    R ESEARCH ARTICLE ScienceAsia 39 (2013): 584–590 doi: 10.2306/scienceasia1513-1874.2013.39.584 Biocontrol of Pythium aphanidermatum by the cellulolytic actinomycetes Streptomyces rubrolavendulae S4 Bajaree Loliama, Tsutomu Morinagab, Saipin Chaiyanana;∗ a Department of Microbiology, Faculty of Science, King Mongkut’s University of Technology Thonburi, 126 Pracha-utid Road, Bangmod, Toongkru, Bangkok 10140 Thailand b Department of Life System Science, Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, 562, Nanatsuka, Shobara, Hiroshima, 727-0023, Japan ∗Corresponding author, e-mail: [email protected] Received 7 Jan 2013 Accepted 18 Sep 2013 ABSTRACT: Streptomyces rubrolavendulae (Yen) S4, isolated from a termite mound in Kanchanaburi, Thailand, was used to control the seedling damping-off disease of the horticultural plant Joseph’s coat caused by Pythium aphanidermatum (Edson) Fitz. In a previous study, S. rubrolavendulae S4 was shown to strongly inhibit the growth of P. aphanidermatum on potato dextrose agar. This study investigated the modes of the antagonistic action of S. rubrolavendulae S4 on P. aphanidermatum. On carboxymethyl cellulose medium, S. rubrolavendulae S4 produced the highest cellulase activity of 65 U/ml in 5 days. The S. rubrolavendulae culture supernatant, with and without heat treatment, was tested for fungal growth inhibition using an agar well-diffusion method. The inhibitory effect was retained with the heat inactivated culture supernatant, indicating that the inhibition was derived from an antifungal compound rather than an enzyme produced by S. rubrolavendulae S4. The parasitic activity of S. rubrolavendulae S4 upon P. aphanidermatum was demonstrated by light and scanning electron micrographs. Joseph’s coat (Amaranthus tricolor) seedlings were grown in peat mosses inoculated with S.
    [Show full text]
  • Integrated Management of Damping-Off Diseases. a Review Jay Ram Lamichhane, Carolyne Durr, André A
    Integrated management of damping-off diseases. A review Jay Ram Lamichhane, Carolyne Durr, André A. Schwanck, Marie-Hélène Robin, Jean-Pierre Sarthou, Vincent Cellier, Antoine Messean, Jean-Noel Aubertot To cite this version: Jay Ram Lamichhane, Carolyne Durr, André A. Schwanck, Marie-Hélène Robin, Jean-Pierre Sarthou, et al.. Integrated management of damping-off diseases. A review. Agronomy for Sustainable De- velopment, Springer Verlag/EDP Sciences/INRA, 2017, 37 (2), 25 p. 10.1007/s13593-017-0417-y. hal-01606538 HAL Id: hal-01606538 https://hal.archives-ouvertes.fr/hal-01606538 Submitted on 16 Mar 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Copyright Agron. Sustain. Dev. (2017) 37: 10 DOI 10.1007/s13593-017-0417-y REVIEW ARTICLE Integrated management of damping-off diseases. A review Jay Ram Lamichhane1 & Carolyne Dürr2 & André A. Schwanck3 & Marie-Hélène Robin4 & Jean-Pierre Sarthou5 & Vincent Cellier 6 & Antoine Messéan1 & Jean-Noël Aubertot3 Accepted: 8 February 2017 /Published online: 16 March 2017 # INRA and Springer-Verlag France 2017 Abstract Damping-off is a disease that leads to the decay of However, this still is not the case and major knowledge gaps germinating seeds and young seedlings, which represents for must be filled.
    [Show full text]
  • Metalaxyl-M-Resistant Pythium Species in Potato Production Areas of the Pacific Northwest of the U.S.A
    Am. J. Pot Res (2009) 86:315–326 DOI 10.1007/s12230-009-9085-z Metalaxyl-M-Resistant Pythium Species in Potato Production Areas of the Pacific Northwest of the U.S.A. Lyndon D. Porter & Philip B. Hamm & Nicholas L. David & Stacy L. Gieck & Jeffery S. Miller & Babette Gundersen & Debra A. Inglis Published online: 3 April 2009 # Potato Association of America 2009 Abstract Several Pythium species causing leak on potato information is lacking on the distribution of MR isolates in are managed by the systemic fungicide metalaxyl-M. the Pacific Northwest. Soil samples from numerous fields Metalaxyl-M-resistant (MR) isolates of Pythium spp. have (312) cropped to potatoes in Idaho (140), Oregon (59), and been identified in potato production areas of the U.S.A., but Washington (113) were assayed using metalaxyl-M- amended agar for the presence of MR isolates of Pythium in 2004 to 2006. Altogether, 1.4%, 42.4% and 32.7% of the L. D. Porter (*) fields from these states, respectively, were positive for MR Vegetable and Forage Crops Research Unit, USDA-ARS, Pythium. Isolates of Pythium ultimum that were highly 24106 N. Bunn Road, Prosser, WA 99350, USA resistant to metalaxyl were recovered from 53 fields e-mail: [email protected] representing ID, OR, and WA. Greater than 50% of the : Pythium soil population consisted of MR isolates in ten of P. B. Hamm S. L. Gieck 64 fields from Oregon and Washington. Nine species of Department of Botany & Plant Pathology, Hermiston Agricultural Research and Extension Center, Pythium were recovered from soil samples, of which MR P.
    [Show full text]
  • Characterization and Identification of Pythium On
    CHARACTERIZATION AND IDENTIFICATION OF PYTHIUM ON SOYBEAN IN NORTH DAKOTA A Dissertation Submitted to the Graduate Faculty Of the North Dakota State University Of Agriculture and Applied Science By Kimberly Korthauer Zitnick-Anderson In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY Major Department: Plant Pathology November 2013 Fargo, North Dakota North Dakota State University Graduate School Title Identification and characterization of Pythium spp. on Glycine max (soybean) in North Dakota By Kimberly Korthauer Zitnick-Anderson The Supervisory Committee certifies that this disquisition complies with North Dakota State University’s regulations and meets the accepted standards for the degree of DOCTOR OF PHILOSOPHY SUPERVISORY COMMITTEE: Dr. Berlin Nelson Chair Dr. Steven Meinhardt Dr. Jay Goos Dr. Laura Aldrich-Wolfe Approved: Dr. Jack Rasmussen 11/08/2013 Date Department Chair ABSTRACT The Oomycete Pythium comprises one of the most important groups of seedling pathogens affecting soybean, causing both pre- and post-emergence damping off. Numerous species of Pythium have been identified and found to be pathogenic on a wide range of hosts. Recent research on Pythium sp. infecting soybean has been limited to regions other than the Northern Great Plains and has not included North Dakota. In addition, little research has been conducted on the pathogenicity of various Pythium species on soybean or associations between Pythium communities and soil properties. Therefore, the objectives of this research were to isolate and identify the Pythium sp. infecting soybean in North Dakota, test their pathogenicity and assess if any associations between Pythium sp. and soil properties exist. Identification of the Pythium sp.
    [Show full text]
  • Molecular Diagnostics and Detection of Oomycetes on Fiber Crops
    plants Review Molecular Diagnostics and Detection of Oomycetes on Fiber Crops Tuhong Wang 1 , Chunsheng Gao 1, Yi Cheng 1 , Zhimin Li 1, Jia Chen 1, Litao Guo 1 and Jianping Xu 1,2,* 1 Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, China; [email protected] (T.W.); [email protected] (C.G.); [email protected] (Y.C.); [email protected] (Z.L.); [email protected] (J.C.); [email protected] (L.G.) 2 Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada * Correspondence: [email protected] Received: 15 May 2020; Accepted: 15 June 2020; Published: 19 June 2020 Abstract: Fiber crops are an important group of economic plants. Traditionally cultivated for fiber, fiber crops have also become sources of other materials such as food, animal feed, cosmetics and medicine. Asia and America are the two main production areas of fiber crops in the world. However, oomycete diseases have become an important factor limiting their yield and quality, causing devastating consequences for the production of fiber crops in many regions. To effectively control oomycete pathogens and reduce their negative impacts on these crops, it is very important to have fast and accurate detection systems, especially in the early stages of infection. With the rapid development of molecular biology, the diagnosis of plant pathogens has progressed from relying on traditional morphological features to the increasing use of molecular methods. The objective of this paper was to review the current status of research on molecular diagnosis of oomycete pathogens on fiber crops.
    [Show full text]
  • Virulence of Pythium Species Isolated from Wheat Fields in Eastern Washington
    Virulence of Pythium Species Isolated from Wheat Fields in Eastern Washington R. W. Higginbotham, Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6420; T. C. Paulitz, USDA-ARS, Root Disease and Biological Control Unit, Pullman, WA 99164-6430; and K. K. Kidwell, Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6420 wheat. Even though previous results dem- ABSTRACT onstrated that a number of Pythium spp. Higginbotham, R. W., Paulitz, T. C., and Kidwell, K. K. 2004. Virulence of Pythium species are pathogenic to wheat, it is not known isolated from wheat fields in eastern Washington. Plant Dis. 88:1021-1026. whether variation in virulence exists among isolates within a given species, Although Pythium root rot in wheat (Triticum aestivum) is well documented, limited information since only one isolate of each Pythium spp. is available concerning which species of Pythium are most responsible for disease damage. The was typically evaluated (3,14). Due to objective of this study was to examine the variation in virulence on wheat among isolates of variation in the distribution of Pythium Pythium collected from cereal grain fields in eastern Washington. Isolates of nine Pythium spe- spp. across environments (19), it is impor- cies were tested for virulence on spring wheat cultivars Chinese Spring and Spillman. Cultivars were planted in pasteurized soil infested with Pythium isolates and placed in a growth chamber tant to know which isolates within a given maintained at a constant 16°C and ambient humidity. Plant height, length of the first true leaf, species are the most virulent, especially for and number of seminal roots were recorded, and roots were digitally scanned to create computer germ plasm evaluations, where the goal is files that were analyzed using WinRhizo software.
    [Show full text]
  • Diversity of Pythium Spp. Associated with Soybean Damping-Off, and Management Implications by Using Foliar Fungicides As Seed Treatments Shrishail S
    Navi et al. Phytopathology Research (2019) 1:8 https://doi.org/10.1186/s42483-019-0015-9 Phytopathology Research RESEARCH Open Access Diversity of Pythium spp. associated with soybean damping-off, and management implications by using foliar fungicides as seed treatments Shrishail S. Navi* , Tra Huynh, Chase G. Mayers and Xiao-Bing Yang Abstract Soybean (Glycine max) seedlings with symptoms of Pythium damping-off were collected in northeastern Iowa soybean fields and processed for isolation of the causal agents on both potato dextrose agar (PDA) and pimaricin-, ampicillin-, rifampicin-, and pentachloronitrobenzene (PARP)-containing media. Isolates were identified based on morphological characteristics, growth rates, along with sequence data for the nuclear rDNA ITS1–5.8S-ITS2 region (ITS barcode). Nine isolates were identified via NCBI BLASTn search of sequences available in GenBank: one isolate of Pythium orthogonon; three isolates of P. inflatum; two isolates of P. ultimum var. ultimum; one isolate of P. torulosum; and two isolates of P. ultimum var. ultimum or P. ultimum var. sporangiferum. Pathogenicity of all the nine isolates, along with a positive control (P. irregulare), was tested in greenhouse conditions on soybean variety Pioneer 22T61R. Soybean seeds were planted in potting mixture inoculated with Pythium inoculum fermented on sterilized proso millet grains. The Pythium spp. were subsequently re-isolated from symptomatic plants. Average incidence of Pythium damping-off across isolates was 27.4% but varied among isolates, ranging from 1.2 to 79.8%. Among the Pythium spp. collected in this single location, the most aggressive isolate was selected to test the efficacy of seed treatments using foliar fungicides in artificially-inoculated field conditions.
    [Show full text]
  • Root and Soil-Borne Oomycetes and Fungi Associated with Torreya
    202 Life: The Excitement of Biology 1 (4) Root and Soil-borne Oomycetes (Heterokontophyta) and Fungi Associated with the Endangered Conifer, Torreya taxifolia Arn. (Taxaceae) in Georgia and Florida, USA1 Lydia I. Rivera Vargas2 and Vivian Negron-Ortiz3 Abstract: A systematic survey was conducted to isolate and identify root and soil-borne oomycetes and fungi associated with the rare and endangered southeastern USA conifer, Torreya taxifolia Arn. Twenty four trees showing different degrees of decline were sampled at two different sites: Torreya State Park, Liberty County, Florida (n = 12) and US Corps of Engineers in Decatur, Georgia (n = 12). All T. taxifolia trees sampled showed moderate to severe levels of decline (100% decline incidence) based on criteria, such as poor development of trees, stunting and fragility. Disease severity was higher, and trees were smaller with poor development at Florida sites, showing an average height of 89 cm, and a diameter at breast height (DBH) of 5 cm compared to trees in Georgia’s site (174 cm h and 10.6 cm DBH in average) In addition to decline, root necrosis and stem cankers were observed in 45.8 % of trees examined. A diverse fungal community was associated with declining trees. Twenty eight fungal genera were identified belonging to the Oomycetes, Zygomycetes, Ascomycetes, Basidiomycetes and anamorphic fungi. Anamorphic fungi, Oomycetes, and Zygomycetes were the dominant groups associated with T. taxifolia. Pestalotiopsis spp., Fusarium spp. and Pythium spp. were the most common genera. Most isolates were obtained from root tissue. Seventy four percent (74%) of isolates were from samples collected at a Georgia site.
    [Show full text]