DOCSLIB.ORG

Phytophthora Capsici on Vegetable Crops: Research Progress and Management Challenges

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Phytophthora Capsici on Vegetable Crops: Research Progress and Management Challenges Mary K. Hausbeck Michigan State University, East Lansing Kurt H. Lamour The University of Tennessee, Knoxville Phytophthora capsici on Vegetable Crops: Research Progress and Management Challenges Phytophthora capsici was first described fenoxam was being applied by some grow- reported that 45 species of cultivated by Leon H. Leonian at the New Mexico ers, and the sensitivity of natural popula- plants and weeds, representing 14 families Agricultural Research station in Las Cru- tions of P. capsici in Michigan to of flowering plants, were susceptible to P. ces in 1922 (65). In his report, he de- mefenoxam was unknown at that time. capsici. They found 19 species in 8 fami- scribed a novel species of Phytophthora Here we review recent advances in our lies that were highly susceptible, with the that caused considerable damage to chili understanding of P. capsici’s biology, in roots and crowns completely rotting 7 to pepper plants in the fall of 1918. A year particular the role of sexual reproduction, 10 days after inoculation. This was the later, the disease reappeared at the same and provide an overview of some of the widest host range study conducted to date. site and also affected surrounding farms. management challenges presented by this Beans, lima beans, and soybeans were During the late 1930s and early 1940s, information. reported (87) to be “immune” to P. capsici recurrent problems with P. c a psi c i in the infection under greenhouse conditions Arkansas River Valley of Colorado were Host Range highly favorable to infection. It is signifi- described on several vegetable hosts (51– and Disease Symptoms cant, therefore, that in the summers of 55,103). The first reported occurrence of P. 2000 and 2001, P. capsici was isolated capsici on a cucurbit crop occurred in In Michigan, there are 32,356 ha of from five commercial cultivars of lima 1937, when a 3.2-ha field of cucumbers vegetables (currently valued at approxi- bean in Delaware, Maryland, and New became diseased resulting in 100% of the mately $134 million) that are highly sus- Jersey (21). Also, P. capsici has recently fruit rotting (51). By 1940, P. capsici had ceptible to crown, root, and fruit rot caused been isolated from commercial snap bean also been described on eggplant, honeydew by P. capsici (Table 1). It is estimated that fields in northern Michigan, adding this melon fruit, summer squash, and tomato when weather favors P. capsici, up to 25% crop to the long list of susceptible crops fruit (52,103). The disease on tomatoes of the state’s value of these vulnerable (35). These snap bean fields had a history was reportedly so severe that the viability vegetables has been lost to disease. Indi- of zucchini cropping and P. capsici infesta- of the processing tomato industry in the vidual producers have experienced devas- tion. All isolates from snap bean were region was threatened. tating losses. When a farm in southern pathogenic to cucumber fruit, and select These early reports mirror the situation Michigan was unable to harvest 121.4 ha isolates were pathogenic to soybean plants with P. capsici today on many modern of diseased pickling cucumbers, an esti- under laboratory conditions (36). vegetable production farms, especially mated $300,000 was lost, along with a Disease caused by P. capsici may ini- those in the eastern United States $40,000 loss on approximately 40.5 ha of tially occur in the low areas of a field (4,72,84,94). Our research was initiated in processing tomatoes. Due to the impact of where water accumulates. Growers often 1997, when crop losses caused by P. cap- P. capsici on this farm’s ability to meet assume that stunting or death of plants in sici threatened to bankrupt a number of contractual obligations for cucumbers, such areas is due to the “waterlogging” of vegetable producers in Michigan. Growers production of this crop was discontinued the roots, but infection by P. capsici may wanted to know why crop rotation and the (57). While ranked nationally as the num- be to blame. Under warm (25 to 30°C), use of fungicides in well-drained fields had ber one producer and processor of cucum- not provided adequate protection against bers for pickling, Michigan also is a major full-scale epidemics. At that time, there midwestern supplier of several vegetables for fresh consumption and for processing Table 1. Crops susceptible to Phytophthora were fundamental gaps in our understand- capsici under field conditions ing of P. capsici’s epidemiology in Michi- (49). In the north-central region of the gan, and it was difficult to answer these United States, P. capsici also is a reported Cucurbitaceae Solanaceae Leguminosae questions with any degree of certainty. We problem on cucumber in Wisconsin Cantaloupe Bell pepper Snap bean did not recognize the extent to which sex- (95,96), on pumpkin in Illinois (5), and on Cucumber Hot pepper Lima bean ual recombination and genetic diversity pepper and cucurbit crops in Ohio (72). Gourd Eggplant could influence management options and The occurrence of P. capsici throughout Honeydew Tomato melon success. In particular, the fungicide me- many vegetable growing regions in the United States has prompted recent research Pumpkin in Virginia (100), New York (70), Florida Muskmelon Corresponding author: M. K. Hausbeck (69), Arizona (68), North Carolina (66), Summer E-mail: [email protected] squash and Georgia (91). Watermelon P. capsici affects a wide range of solana- Winter squash Publication no. D-2004-1007-01F ceous and cucurbit hosts worldwide Zucchini © 2004 The American Phytopathological Society (17,27,43). In 1967, Satour and Butler (87) 1292 Plant Disease / Vol. 88 No. 12 wet conditions, root and crown infection of soil onto the cotyledons of emerging cu- located along the surface water drainage pepper, zucchini, squash, and pumpkin cumbers, the entire 24.3-ha planting was pattern. P. c a psi c i was recovered from typically causes permanent wilt and plant killed. Similarly, extremely rainy weather crown, stem, and leaf tissue (35). death (Fig. 1D–F,L). Plants often have that saturates soil for extended periods can While plant death is always a concern brown to black discolored roots and/or prompt a severe root and crown rot that for vegetable producers, fruit rot seems to crowns. In contrast, infected cucumber and kills even established tomato plants. Dis- be especially insidious on cucurbits. In tomato plants may be relatively asympto- ease symptoms on snap beans include general, infected cucurbit fruit initially matic or exhibit limited root rot and plant water-soaking on the leaves, stem necrosis exhibit dark, water-soaked lesions (Fig. stunting (Fig. 1A,B,M,N). However, when (Fig. 1O), and overall decline. Disease 1C,I), followed by a distinctive white a rainstorm splashed P. capsici–infested symptoms were most severe on bean plants “powdered-sugar” layer of spores on the Fig. 1. Symptoms of disease caused by Phytophthora capsici on: A to C, cucumber; D and E, yellow squash; F, hard squash; G, zuc- chini; H, immature pumpkin; I, spaghetti squash; J, bell pepper; K and L, banana pepper; M and N, tomato; and O, snap bean. Plant Disease / December 2004 1293 surface of the fruit 2 to 3 days later (Fig. The Pathogen composed of coenocytic mycelium which 1A,G,H). While P. capsici regularly causes may give rise to lemon-shaped sporangia a blight of pepper fruit in other growing Early investigators recognized that the borne on long caducous pedicels (1). When regions (84), this is not a common occur- genus Phytophthora exhibited striking sporangia are immersed in free water, they rence in Michigan and has been observed dissimilarities to many other fungal organ- differentiate to produce 20 to 40 bi-motile only occasionally in the last several years isms, but a full resolution of its taxonomic swimming zoospores (Fig. 2) (8). Long- (Fig. 1J,K). Cucumber plants appear to and evolutionary standing would not be term survival outside of host tissue is ac- tolerate root infection by P. capsici, yet the made until DNA sequence analysis was complished by the oospore (2,3,10,42,58– fruit are especially susceptible. In Michi- completed by Forster et al. in 1990. They 60), which has a thick, multilayered wall gan, fields of healthy-appearing cucumber found that oomycetes are more closely containing β-glucan and cellulose (27). vines with mature fruit have been aban- related to heterokont photosynthetic algae Oospores require a dormancy period of at doned in the field at harvest, or semi-truck than to members of the kingdom Fungi least a month (27,88) before germinating loads of fruit rejected at the processing (29). The modern description of P. capsici directly or by forming sporangia (Fig. 2). facility, due to rot. In our studies, we rou- as a species falls into Waterhouse’s Group tinely observe a delay of at least 48 hours in II (101) and is characterized by sporangia Sexual Reproduction that are conspicuously papillate with am- symptom expression in cucumber following and Oospores successful penetration by P. c a p s i c i (K. H. phigynous oospores generally forming Lamour and M. K. Hausbeck, unpublished only when A1 and A2 mating types are Approximately half of the 60 recognized results). A similar 3- to 6-day lag prior to paired. Information concerning the differ- species in the genus Phytophthora are symptom expression for P. c a p si c i infecting ent spore types produced by members of homothallic (self-fertile), and for these peppers has been described previously by the genus Phytophthora accumulated species, a single isolate is able to complete Schlub (89). This delay explains why slowly between 1940 and 1970.
Load more

Recommended publications
  • Phytophthora Blight of Cucurbits, Pepper, Tomato, and Eggplant - Thomas A
    Phytophthora Blight of Cucurbits and Peppers March 2021 Phytophthora blight, caused by an oomycete (Protist) Phytophthora capsici, is a serious threat to vegetable crops worldwide, particularly legumes, cucurbits and solanaceous plants. It is a fast spreading, aggressive disease, capable of causing complete crop destruction. Many vegetable growers are familiar with a close relative of this disease - late blight of potato and tomato, caused by Phytophthora infestans. In British Columbia (B.C.), it was first detected on pepper, pumpkin, squash, gourds, and eggplants in market gardens in Kelowna area in 2004; however, the disease has not been observed thereafter. In the USA, P. capsici is known to affect many crops, particularly in the eastern states. Hosts Phytophthora capsici is known to infect a wide range of vegetable crops, including crops belong to cucurbitaceae (e.g. melon, cucumber, pumpkin, squash), solanaceae (e.g. peppers, tomato, eggplant) and leguminosae (e.g. snap bean, lima bean), and many weeds. Under the laboratory conditions, it has been demonstrated to infect crops such as root crops (e.g. beet, carrot, radish, turnip, onion), greens (e.g. spinach, swiss-chard), legumes (e.g. alfalfa, soybean, snow pea) and okra. Symptoms Phytophthora capsici may affect all parts of the plant, causing a wide range of symptoms. It may cause pre- and post-emergence damping-off, stem and vine blight, wilting and fruit rot. Symptoms can appear as fast as 3 to 4 days after initial infection when temperatures are warm. Damping-off may occur both before and after emergence of seedlings in susceptible crops in the spring. Symptoms include a watery rot near the soil line, wilting, and subsequent plant death.
    [Show full text]
  • Managing Phytophthora Blight of Peppers and Cucurbits
    W 810 Managing Phytophthora Blight of Peppers and Cucurbits March 2019 Zachariah Hansen, Assistant Professor and Extension Specialist Timothy Siegenthaler, Graduate Assistant Andrew Swaford, Student Assistant Department of Entomology and Plant Pathology Disease Overview Phytophthora blight is a general term for crown rot, root rot and fruit rot of vegetables caused by the oomycete (water mold) Phytophthora capsici. It is a serious disease of peppers and cucurbits, but it can also afect other vegetables including tomato, eggplant and beans. The disease is best managed through prevention because once it becomes established in a feld it is nearly impossible to remove. The pathogen produces long-lived spores, called oospores, that can survive in the soil for 10 years or more. When con- ditions are warm and wet, the disease progresses rapidly through the production of another spore type called sporangia. When conditions are favorable for disease, millions of sporangia are produced, each releasing up to 40 swimming zoospores which are responsible for starting new infections. These spores move through splashing water and can easily spread down rows through fowing water or contaminate irrigation sources during rain events. 1 Managing Phytophthora Blight of Peppers and Cucurbits Diagnosing Phytophthora blight Peppers Symptoms on peppers include sudden wilting and dark lesions near the soil line (Fig. 1). Root rot may also be observed. Fruit are commonly afected and display a tan, water-soaked soft rot with a thin layer of white powdery mold visible to the naked eye (Fig. 2). Afected plants will often die shortly after symptoms appear. Symptoms of Phytophthora blight on pepper may be confused with southern blight, which also presents rapid wilting and a dark lesion as the soil line.
    [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]
  • Vegetable Notes for Vegetable Farmers in Massachusetts
    University of Massachusetts Extension Vegetable Notes For Vegetable Farmers in Massachusetts Volume 26, Number 6 May 15, 2014 IN THIS ISSUE: CROP CONDITIONS Crop Conditions Field planting continued steadily this week. In northern New England fields Pest Alerts have been slow to dry out, but farther south, wet soils have not been a barrier for the most part. The short Mother’s Day hot spell boosted crop growth as well as Preparing for Phytophthora capsici plant sales. Overall, crop growth continues to be slow in response to cool tem- Leafminer on Spinach peratures and cloudy skies. Growers are using season extension tools more than Summer Nitrogen Management ever, including seeding sweet corn under plastic later than usual, and covering large fields of early brassicas to push them along. Some growers are waiting to Fungicide Resistance Management transplant early squash, cukes and other for Cucurbit Diseases fruiting crops, while others are taking Events & Classes the chance that row cover or plastic low tunnels will provide protection from cold or wind. High tunnel greens are also slow. June market goals are looming – whether at the farmstand, farmers market, wholesale accounts, or CSA farmshares - and crops aren’t quite keeping up. Asparagus harvest started about a week late but is now in full swing. Rhu- barb and fiddleheads are also being harvested. Spring pests are up and running, including maggot flies, flea beetles, spinach and beet leaf miner, and Botrytis – see pest alerts. It’s almost time to start monitoring for ECB, The New England Crop Weather weekly report gives GDD from across the five CEW, and squash vine borer.
    [Show full text]
  • Pepper & Eggplant Disease Guide
    Pepper & Eggplant Disease Guide Edited by Kevin Conn Pepper & Eggplant Disease Guide* A PRACTICAL GUIDE FOR SEEDSMEN, GROWERS AND AGRICULTURAL ADVISORS Editor Kevin Conn Contributing Authors Supannee Cheewawiriyakul; Chiang Rai, Thailand Kevin Conn; Woodland, CA, USA Brad Gabor; Woodland, CA, USA John Kao; Woodland, CA, USA Raquel Salati; San Juan Bautista, CA, USA All authors are members of the Seminis® Vegetable Seeds, Inc.’s Plant Health Department. 2700 Camino del Sol • Oxnard, CA 93030 37437 State Highway 16 • Woodland, CA 95695 Last Revised in 2006 *Not all diseases affect both peppers and eggplants. Preface This guide provides descriptions and photographs of the more commonly found diseases and disorders of pepper and eggplant worldwide. For each disease and disorder, the reader will find the common name, causal agent, distribution, symptoms, conditions necessary for disease or symptom development, and control measures. The photographs illustrate characteristic symptoms of the diseases and disorders included in this guide. It is important to note, however, that many factors can influence the appearance and severity of symptoms. The primary audience for this guide includes pepper and eggplant crop producers, agricultural advisors, farm managers, agronomists, food processors, chemical companies and seed companies. This guide should be used in the field as a quick reference for information about some common pepper and eggplant diseases and their control. However, diagnosis of these diseases and disorders using only this guide is not recommended nor encouraged, and it is not intended to be substituted for the professional opinion of a producer, grower, agronomist, pathologist and similar professional dealing with this specific crop.
    [Show full text]
  • Suppression of Phytophthora Capsici Infection and Promotion of Tomato Growth by Soil Bacteria
    Author’s Accepted Manuscript Suppression of Phytophthora capsici infection and promotion of tomato growth by soil bacteria Sharifah Farhana Syed-Ab-Rahman, Yawen Xiao, Lilia C. Carvalhais, Brett J. Ferguson, Peer M. Schenk www.elsevier.com PII: S2452-2198(18)30139-3 DOI: https://doi.org/10.1016/j.rhisph.2018.11.007 Reference: RHISPH137 To appear in: Rhizosphere Received date: 28 October 2018 Revised date: 25 November 2018 Accepted date: 25 November 2018 Cite this article as: Sharifah Farhana Syed-Ab-Rahman, Yawen Xiao, Lilia C. Carvalhais, Brett J. Ferguson and Peer M. Schenk, Suppression of Phytophthora capsici infection and promotion of tomato growth by soil bacteria, Rhizosphere, https://doi.org/10.1016/j.rhisph.2018.11.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Suppression of Phytophthora capsici infection and promotion of tomato growth by soil bacteria Sharifah Farhana Syed-Ab-Rahman1*, Yawen Xiao1, Lilia C. Carvalhais2, Brett J. Ferguson3, Peer M. Schenk1 1Plant-Microbe Interactions Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072 Australia. 2Centre of Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Ecosciences Precinct, GPO Box 267, Queensland 4001 Australia.
    [Show full text]
  • Ecologically Based Approaches to Management of Phytophthora Blight on Bell Pepper
    Jean Beagle Ristaino North Carolina State University, Raleigh Stephen A. Johnston Rutgers Agricultural Research and Extension Center, Bridgeton, NJ Symptoms and Life Cycle P. capsici can infect virtually every part of the pepper plant. The pathogen causes a root and crown rot on pepper (Fig. 1) and also forms distinctive black lesions on the Ecologically Based stem (Fig. 2). P. capsici can also infect the leaves and causes lesions that are circular, grayish brown, and water-soaked (Fig. 3). Leaf lesions and stem lesions are common Approaches to when inoculum is splash dispersed from the soil to lower portions of the plant. The pathogen can also infect fruit and causes Management lesions that are typically covered with white sporangia, a sign of the pathogen (Fig. 4). P. capsici typically causes a fruit of Phytophthora Blight rot or stem rot on cucumbers and squash (Fig. 5). P. capsici reproduces by both sexual and asexual means (Fig. 6). The pathogen pro- on Bell Pepper duces two mating types, known as the A1 and A2. These are actually compatibility types and do not correspond to dimorphic forms. Each mating type produces hor- mones that are responsible for gametangia differentiation in the opposite mating type. Both A1 and A2 mating types are common Phytophthora blight, caused by the oo- input of knowledge concerning a pathogen in fields in North Carolina and have also mycete pathogen, Phytophthora capsici, is life cycle, and secondarily, when necessary, been identified within the same plant (59). a devastating disease on bell pepper and on physical, chemical, and biological sup- P.
    [Show full text]
  • The Oomycete Broad-Host-Range Pathogen Phytophthora Capsici
    MOLECULAR PLANT PATHOLOGY (2012) 13(4), 329–337 DOI: 10.1111/J.1364-3703.2011.00754.X Pathogen profile The oomycete broad-host-range pathogen Phytophthora capsici KURT H. LAMOUR1, REMCO STAM2,3, JULIETTA JUPE3 AND EDGAR HUITEMA3,* 1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA 2Plant Pathology Programme, James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK 3Division of Plant Science, College of Life Sciences, University of Dundee at JHI, Errol Road, Invergowrie, Dundee DD2 5DA, UK ally, hyphae do not emerge from infected plants or fruit SUMMARY (common with Pythium infections) and all that is visible on the Phytophthora capsici is a highly dynamic and destructive patho- surface of an infected plant is sporangia. gen of vegetables. It attacks all cucurbits, pepper, tomato and Importance: Phytophthora capsici presents an oomycete worst- eggplant, and, more recently, snap and lima beans. The disease case scenario to growers as it has a broad host range, often incidence and severity have increased significantly in recent produces long-lived dormant sexual spores, has extensive geno- decades and the molecular resources to study this pathogen are typic diversity and has an explosive asexual disease cycle. It is growing and now include a reference genome. At the population becoming increasingly apparent that novel control strategies are level, the epidemiology varies according to the geographical loca- needed to safeguard food production from P. capsici and other tion, with populations in South America dominated by clonal oomycetes. Considering that P. capsici is easy to grow, mate and reproduction, and populations in the USA and South Africa com- manipulate in the laboratory and infects many plant species, this posed of many unique genotypes in which sexual reproduction is pathogen is a robust model for investigations, particularly those common.
    [Show full text]
  • Mhora Udel 0060D 13546.Pdf
    A GENOMICS BASED APPROACH TO MANAGING DOWNY MILDEW OF LIMA BEAN by Terence Tariro Mhora A dissertation submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant and Soil Sciences Fall 2018 © 2018 Terence Tariro Mhora All Rights Reserved A GENOMICS BASED APPROACH TO MANAGING DOWNY MILDEW OF LIMA BEAN by Terence Tariro Mhora Approved: __________________________________________________________ Erik Ervin, Ph.D. Chair of the Department of Plant and Soil Sciences Approved: __________________________________________________________ Mark Rieger, Ph.D. Dean of the College of Agriculture and Natural Resources Approved: __________________________________________________________ Douglas J. Doren, Ph.D. Interim Vice Provost for the Office of Graduate and Professional Education I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ Nicole M. Donofrio, Ph.D. Professor in charge of dissertation I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ Thomas A. Evans, Ph.D. Professor in charge of dissertation I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ Randall J. Wisser, Ph.D. Member of dissertation committee I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy.
    [Show full text]
  • Diversity and Management of Phytophthora in Southeast Asia
    Diversity and Management of Phytophthora in Southeast Asia Editors: André Drenth and David I. Guest Australian Centre for International Agricultural Research Canberra 2004 Diversity and Management of Phytophthora in Southeast Asia Edited by André Drenth and David I. Guest ACIAR Monograph 114 (printed version published in 2004) The Australian Centre for International Agricultural Research (ACIAR) was established in June 1982 by an Act of the Australian Parliament. Its mandate is to help identify agricultural problems in developing countries and to commission collaborative research between Australian and developing country researchers in fields where Australia has a special research competence. Where trade names are used this constitutes neither endorsement of nor discrimination against any product by the Centre. ACIAR MONOGRAPH SERIES This peer-reviewed series contains the results of original research supported by ACIAR, or material deemed relevant to ACIAR’s research objectives. The series is distributed internationally, with an emphasis on developing countries. © Australian Centre for International Agricultural Research, GPO Box 1571, Canberra, ACT 2601, Australia Drenth, A. and Guest, D.I., ed. 2004. Diversity and management of Phytophthora in Southeast Asia. ACIAR Monograph No. 114, 238p. ISBN 1 86320 405 9 (print) 1 86320 406 7 (online) Technical editing, design and layout: Clarus Design, Canberra, Australia Printing: BPA Print Group Pty Ltd, Melbourne, Australia Diversity and Management of Phytophthora in Southeast Asia Edited by André Drenth and David I. Guest ACIAR Monograph 114 (printed version published in 2004) Foreword The genus Phytophthora is one of the most important plant pathogens worldwide, and many economically important crop species in Southeast Asia, such as rubber, cocoa, durian, jackfruit, papaya, taro, coconut, pepper, potato, plantation forestry, and citrus are susceptible.
    [Show full text]
  • Phytophthora Blight on Beans
    Appendix E Disease Alert PHYTOPHTHORA BLIGHT ON BEANS Phytophthora blight is a devastating disease caused by the water mold Phytophthora capsici. It is well known throughout the United States as a pathogen on solanaceous (bell pepper, hot pepper, eggplant, tomato) and cucurbit crops (cantaloupe, cucumber, gourd, honeydew melon, pumpkin, muskmelon, summer squash, watermelon, winter squash, zucchini), and in recent years has caused problems on snap and lima beans. Phytophthora blight was reported on lima beans in 2000 on crops grown in Delaware, Maryland, and New Jersey. In 2003, the disease was reported on snap beans in Michigan, and in 2008 on snap beans grown on Long Island. In 2009, a Phytophthora blight epidemic struck snap beans fields in Connecticut, resulting in devastating losses. Phytophthora blight symptoms on snap beans are as follows: P. capsici produces large water soaked lesions on the leaves, and as the disease progresses the infected leaves fall off the plant. Lesions on the stems are brown with white powdery areas. White lesions are produced on the pods, and infected areas shrivel and desiccate. Consumed pods are dry, shriveled and leathery. As the name suggests, this water mold thrives in moist environments. The Dillard Lab is conducting research to assess fungicide efficacy for disease control and to evaluate tolerance of several snap bean varieties to P. capsici. Snap bean pods infected with P. capsici turn white and are shriveled. Note senescing and dead leaves. Early stage of Phytophthora blight on snap bean pods and stems. Note premature senescing of infected leaves. .
    [Show full text]
  • Biologically Active Phytophthora Mating Hormone Prepared by Catalytic Asymmetric Total Synthesis
    Biologically active Phytophthora mating hormone prepared by catalytic asymmetric total synthesis Syuzanna R. Harutyunyan*†, Zhijian Zhao†‡§, Tim den Hartog*, Klaas Bouwmeester‡, Adriaan J. Minnaard*¶, Ben L. Feringa*¶, and Francine Govers‡¶ *Department of Organic Chemistry and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands; and ‡Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Binnenhaven 5, 6709 PD, Wageningen, The Netherlands Edited by Laura L. Kiessling, University of Wisconsin, Madison, WI, and approved April 7, 2008 (received for review September 30, 2007) A Phytophthora mating hormone with an array of 1,5-stereogenic centers has been synthesized by using our recently developed methodology of catalytic enantioselective conjugate addition of Grignard reagents. We applied this methodology in a diastereo- and enantioselective iterative route and obtained two of the 16 possible stereoisomers of Phytophthora hormone ␣1. These syn- thetic stereoisomers induced the formation of sexual spores (oospores) in A2 mating type strains of three heterothallic Phyto- phthora species, P. infestans, P. capsici, and P. nicotianae but not in A1 mating type strains. The response was concentration- dependent, and the oospores were viable. These results demon- strate that the biological activity of the synthetic hormone resem- bles that of the natural hormone ␣1. Mating hormones are essential components in the sexual life cycle of a variety of organisms. For plant pathogens like Phytophthora, sexual repro- CHEMISTRY duction is important as a source of genetic variation. Moreover, the Fig. 1. Structure of mating hormone ␣1 (1) (A) and enantioselective CA of thick-walled oospores are the most durable propagules that can Grignard reagents to ␣, ␤-unsaturated thioesters (B).
    [Show full text]