DOCSLIB.ORG

Study of the Barley Yellow Dwarf Virus Species PAV and PAS: Distribution, Virus Quantification and Host Resistance

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Study of the Barley yellow dwarf virus species PAV and PAS: distribution, virus quantification and host resistance Barley Wheat Oat Jana Jarošová, Jana Chrpová, Václav Šíp, Jiban K. Kundu* WDV Crop Research Institute, Prague, the Czech Republic. *E-mail: [email protected], +420-233022402 Background. Barley yellow dwarf (BYD) is one of the most widespread and damaging viral diseases of grasses and cereal crops worldwide. (BYDVs) are a group of related single-stranded RNA viruses assigned to the Luteovirus and Polerovirus genera or unassigned to genera in the family Luteoviridae . Luteoviruses include Barley yellow dwarf virus (BYDV)-PAV, BYDV-PAS, BYDV-MAV, and BYDV-GAV. Poleroviruses include Cereal yellow dwarf virus (CYDV)- RPV. BYDV-SGV, BYDV-RMV and BYDV-GPV are not currently assigned genera. The BYDV species vary strongly in their symptom manifestation, species of efficient aphid vectors, host preferences and in their serological and molecular properties. The BYDV-PAS has been recently separated from BYDV-PAV, the most commonly studied BYDV species. This study was focused on the distribution and characteristics of the PAS. A comparative study of the species PAV and PAS on distribution, virus accumulation and host resistance are described. BYDV quantification. A SYBER green based real time RT-qPCR assay was BYDV distribution. The percentage distribution of individual BYDV species developed for relative BYDV quantification. In the RT-qPCR assay GAPDH, as in comparison with different aspects of samples. 18S rRNA, TUBA and TUBB as normalisation genes of BYDV quantification in barley and oat tissues and a combination of GAPDH, 18S rRNA, TUBB, EIF4A and E1FA for wheat tissues were used. At least three normalization genes are recommended for virus quantification. A: The relative BYDV titre levels in all the oat samples as determined by relative quantification using GAPDH, Ct values distribution of candidate TUBB and 18S rRNA (GAPDH etc), TUBA, EIF4A and EEF1A reference genes in different (EIF4A etc.) and by absolute quantification with cloned species. Values are given as real- standards (absolute). time PCR cycle threshold (Ct) B: The relative BYDV titre levels in the two oat varieties - values. Boxes represent the lower Atego (tolerant) and Saul (susceptible) as determined by A) shows the distribution of BYDV species and upper quartiles with medians; relative quantification using GAPDH, TUBB and 18S rRNA among aphid species (S.a. stands for whiskers illustrate the 10 to 90 (GAPDH), TUBA, EIF4A and EF1A (EIF4A) and by absolute Sitobion avenae; M.d. for Metopolophium percentiles of the samples. All Ct quantification with cloned standards (absolute). The dirhodum; R.m. for Rhopalosiphum values significantly differed absolute numbers were transformed into relative ratios maidis; R.p. for Rhopalosiphum padi, between species (One way so they could be compared. B) shows distribution of individual aphid species among samples, C) shows the effect of plant ANOVA test). being a volunteer plant or not on BYDV species distribution , D) shows the effect of sowing time on BYDV species distribution. Quantitative analysis of BYDV –PAS and BYDV–PAV uptake in winter barley Throughout three years of experimental monitoring of BYDV incidence, PAV resulted in the PAS was the most frequently occurring species infecting cereals, more severe and grasses in the Czech Republic. symptoms and Four species of aphid vectors have been observed in cereal fields: caused a greater Sitobion avenae, Rhopalosiphum padi, Metopolophium dirhodum, R. reduction in maidis. R. maidis and M. dirhodum were recorded as BYDV-PAS vectors, plant height and even though M. dirhodum does not usually transmit BYDV-PAV. yield than PAS. We found a significant difference in virus RNA accumulation between the Comparison of BYDV-PAS and BYDV-PAV in resistance traits PAS and PAV species. In susceptible plants, the virus titre of PAS was greater than that of PAV. Infection with the BYDV-PAV isolate resulted Crop Variety/line VSS PHR (%) GWSR (%) in higher expression of symptoms and also in PAS PAV PAS PAV PAS PAV Range winter WBON116 (Yd2 gene) 1.50 a 2.75 ab 3.9 a 16.0 a 12.6 a 17.2 a 1.7 a greater reduction in plant height and grain barley WBON123 (Yd2 gene) 1.38 a 2.13 a 5.3 a 16.4 a 23.4 ab 29.8 ab 2.3 weight per spike in all tested traits. Doria (Yd2 gene) 3.38 b 3.88 b 0.0 a 21.1 ab 17.4 a 23.8 a 3.0 In general, high levels of resistance were Wysor (Yd2 gene) 1.63 a 2.13 a 9.0 ab 19.6 a 25.4 ab 17.8 a 3.2 Sigra 5.13 c 5.88 c 18.8 bc 35.3 bc 23.9 ab 31.3 ab 5.3 recorded in winter barley breeding lines Finesse 4.88 c 6.25 cd 25.6 c 43.1 c 28.3 abc 44.2 b 6.8 (Wbon116, Wbon123) and varieties (Wysor, Traminer 4.75 c 7.13 de 18.8 bc 40.4 c 36.3 bcd 65.1 c 6.8 Doria) containing the Yd2 gene resistant to Perry 5.88 cd 6.13 cd 21.5 c 43.2 c 48.1 de 62.7 c 7.7 Luran 6.75 de 7.88 ef 17.8 bc 49.4 c 54.8 e 73.2 cd 8.5 both PAV and PAS. Graciosa 7.38 e 8.63 f 26.8 c 68.6 d 44.4 cde 84.0 d 9.7 The winter wheat breeding line PSR3628, a winter PSR 3628 0.75 a 1.17 a 4.3 a 1.8 a 3.0 a 8.0 a 1.0 wheat Svitava 4.13 b 5.63 bcd 6.5 a 11.9 abc 35.4 bcd 48.2 b 3.8 hybrid of wheat and couch grass, was highly Dromos 3.88 b 4.90 b 7.7 a 22.3 bcd 40.0 cd 43.5 b 4.0 resistant to both tested BYDV species. Sparta 4.00 b 4.70 b 12.5 ab 11.0 ab 28.6 bc 51.7 b 4.0 The Svitava, Dromos, Sparta and Banquet Banquet 4.13 b 6.25 d 10.6 a 22.0 bcd 24.0 b 46.0 b 4.3 Roane 4.38 b 6.17 cd 7.4 a 27.8 d 37.1 bcd 57.0 b 6.3 varieties were regarded as moderately Sisson 5.00 bc 6.58 d 11.4 ab 19.9 bcd 38.4 bcd 49.2 b 6.5 resistant in our test. Meritto 4.38 b 5.20 bc 19.3 b 28.6 d 45.3 d 56.9 b 7.5 We noted that the use of two species, Vlada 6.38 cd 6.30 d 11.3 ab 26.1 cd 41.1 d 55.8 b 7.5 SG-S 2703 7.25 d 7.92 e 31.8 c 47.8 e 64.1 e 76.9 c 10.0 namely the varieties carrying the Yd2 gene in Average 4.44 a 5.40 b 13.5 a 27.6 b 33.4 a 46.7 b barley and the line PSR 3628 in wheat, Average VSS (visual symptom score recorded on a scale of 0 to 9, where 0 represents no symptoms), PHR (plant allowed the detection of the sources of height reduction) and GWSR (reduction of grain weight per spike) in barley and wheat varieties (lines) after resistance in all the tested traits. inoculation with BYDV-PAS and BYDV-PAV. Means in the columns followed by the same letter are not significantly different from each other at P=0.05 of the LSD test. Jarošová J, Kundu JK, 2010. Validation of reference genes as internal control for studying viral infections in cereals by quantitative real-time RT-PCR. BMC Plant Biology 10, 146. WSMV Reference: Jarošová et al. 2011. A comparative study of the Barley yellow dwarf virus species PAV and PAS: distribution, virus accumulation and host resistance. Plant Pathology (accepted) C R O P R E S EA R C H I NS T I T U T E, P R A G U E, THE C Z E C H R E P U B L I C The work was funded by projects no. QH81269 Mze ČR and ME10022 MŚMT ČR.
Recommended publications
  • Early Season Population Dynamics and Residual Insecticide Effects on Bird Cherry-Oat Aphid, Rhopalosiphum Padi in Arkansas Winte

    Early Season Population Dynamics and Residual Insecticide Effects on Bird Cherry-Oat Aphid, Rhopalosiphum Padi in Arkansas Winte

    University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 5-2012 Early Season Population Dynamics and Residual Insecticide Effects on Bird Cherry-oat Aphid, Rhopalosiphum padi in Arkansas Winter Wheat Beven McWilliams University of Arkansas, Fayetteville Follow this and additional works at: http://scholarworks.uark.edu/etd Part of the Entomology Commons, and the Plant Pathology Commons Recommended Citation McWilliams, Beven, "Early Season Population Dynamics and Residual Insecticide Effects on Bird Cherry-oat Aphid, Rhopalosiphum padi in Arkansas Winter Wheat" (2012). Theses and Dissertations. 246. http://scholarworks.uark.edu/etd/246 This Thesis 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]. EARLY SEASON POPULATION DYNAMICS AND RESIDUAL INSECTICIDE EFFECTS ON BIRD CHERRY-OAT APHID, RHOPALOSIPHUM PADI IN ARKANSAS WINTER WHEAT EARLY SEASON POPULATION DYNAMICS AND RESIDUAL INSECTICIDE EFFECTS ON BIRD CHERRY-OAT APHID, RHOPALOSIPHUM PADI IN ARKANSAS WINTER WHEAT A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Entomology By Beven McWilliams Rhodes College Bachelor of Science in Biology, 2008 May 2012 University of Arkansas ABSTRACT Bird cherry-oat aphid is a common pest of Arkansas winter wheat. This aphid vectors barley yellow dwarf virus which may cause extensive crop damage and yield loss when wheat is infested by virulent aphids in the fall. Some suggest this damage may be avoided using insecticide seed treatments if growers are unable to delay planting, as is recommended.
  • A Study of the Biology of Rhopalosiphum Padi (Homoptera: Aphididae) in Winter Wheat in Northwestern Indiana J

    A Study of the Biology of Rhopalosiphum Padi (Homoptera: Aphididae) in Winter Wheat in Northwestern Indiana J

    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications: Department of Entomology Entomology, Department of 1987 A STUDY OF THE BIOLOGY OF RHOPALOSIPHUM PADI (HOMOPTERA: APHIDIDAE) IN WINTER WHEAT IN NORTHWESTERN INDIANA J. E. Araya Universidad de Chile John E. Foster University of Nebraska-Lincoln, [email protected] S. E. Cambron Purdue University, [email protected] Follow this and additional works at: http://digitalcommons.unl.edu/entomologyfacpub Part of the Entomology Commons Araya, J. E.; Foster, John E.; and Cambron, S. E., "A STUDY OF THE BIOLOGY OF RHOPALOSIPHUM PADI (HOMOPTERA: APHIDIDAE) IN WINTER WHEAT IN NORTHWESTERN INDIANA" (1987). Faculty Publications: Department of Entomology. 543. http://digitalcommons.unl.edu/entomologyfacpub/543 This Article is brought to you for free and open access by the Entomology, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications: Department of Entomology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 1987 THE GREAT LAKES ENTOMOLOGIST 47 A STUDY OF THE BIOLOGY OF RHOPALOSIPHUM PADI (HOMOPTERA: APHIDIDAE) IN WINTER WHEAT IN NORTHWESTERN INDIANAI J. E. Araya2, J, E. Foster3, and S. E. Cambron 3 ABSTRACT Periodic collections of the bird cherry-oat aphid, Rhopalosiphum padi, dtring two years revealed small populations on winter wheat in Lafayette, Indiana. The greatest numbers were found on volunteer wheat plants before planting. In the autumn, aphids were detected on one-shoot plants by mid-October and also early March. The populations remained small until mid-June. We conclude that the aphid feeding did not significantly affect the plants, but helped spread barley yellow dwarf virus.
  • The Debate on Plant and Crop Biodiversity and Biotechnology

    The Debate on Plant and Crop Biodiversity and Biotechnology

    The Debate on Plant and Crop Biodiversity and Biotechnology Klaus Ammann, [email protected] Version from December 15, 2017, 480 full text references, 117 pp. ASK-FORCE contribution No. 11 Nearly 470 references on biodiversity and Agriculture need still to be screened and selected. Contents: 1. Summary ........................................................................................................................................................................... 3 2. The needs for biodiversity – the general case ................................................................................................................ 3 3. Relationship between biodiversity and ecological parameters ..................................................................................... 5 4. A new concept of sustainability ....................................................................................................................................... 6 4.1. Revisiting the original Brundtland definition of sustainable development ...............................................................................................................7 4.2. Redefining Sustainability for Agriculture and Technology, see fig. 1 .........................................................................................................................8 5. The Issue: unnecessary stigmatization of GMOs .......................................................................................................... 12 6. Types of Biodiversity ......................................................................................................................................................
  • The Occurrence of Aphids on Sweet Maize in South-Eastern Poland

    The Occurrence of Aphids on Sweet Maize in South-Eastern Poland

    ISSN 1644-0692 www.acta.media.pl Acta Sci. Pol. Hortorum Cultus, 14(6) 2015, 39-54 THE OCCURRENCE OF APHIDS ON SWEET MAIZE IN SOUTH-EASTERN POLAND Paweł K. Bereś Institute of Plant Protection – National Research Institute in Poznań, Regional Experimental Station in Rzeszów Abstract. In Poland sweet maize is a small-acreage crop, and because of this no complex plan for the protection of this plant against pests and other harmful organisms has been developed. Since the enforcement of integrated pest management (IPM) in the EU in 2014 the use of chemical control methods has to be supported by relevant data on the biology of the controlled pest. A very limited number of studies have been carried out in Poland on the harmful entomofauna of sweet maize, including aphids. Studies were carried out in 2009–2014 on a field of sweet maize (Zea mays L. var. saccharata), ‘Candle’ cultivar, in south-eastern Poland. In the study years the infestation with aphids was from very low to moderately high. Seven aphid species were identified on sweet maize. The above-ground plant parts were infested with Rhopalosiphum padi L., Metopolophium dirhodum Walk., Sitobion avenae F., Rhopalosiphum maidis Fitch., Aphis fabae Scop. and Myzus persicae Sulz. A small number of individuals representing Tetraunera ulmi L. were found on the root systems of plants. R. padi was the dominant aphid species in all study years. M. dir- hodum and S. aveane occurred in lower numbers, while other aphid species formed single colonies. Aphids began to infest maize plants from the last ten days of April or from May, and ended feeding at the end of September or in the first half of October.
  • Cereal Aphids G

    Cereal Aphids G

    G1284 (Revised August 2005) Cereal Aphids G. L. Hein, Extension Entomologist, J. A. Kalisch, Extension Technologist, and J. Thomas, Research Coordinator to living young. A female may produce two to three young Identification and general discussion of the cereal per day under warm conditions, and females may mature in aphid species most commonly found in Nebraska small 7-10 days. This tremendous reproduction potential can result grains, corn, sorghum and millet. in rapid aphid population buildup. Males of some species are seldom if ever seen. Cereal aphids can be a serious threat to several Nebraska Both winged and wingless aphids may be present in the crops. Aphid feeding may cause direct damage to the plant or field. Winged forms are produced when the quality of the host result in transmission of plant diseases. Aphids also may cause plant declines, such as at maturity. Other factors, including damage by injecting toxic salivary secretions during feeding. temperature, photoperiod or seasonality, and population density In Nebraska the most serious cereal aphid problems result also may be involved. The ability of aphids to use flight for from Russian wheat aphid infestations on wheat and barley dispersal is an important factor that contributes to the status and greenbug infestations on sorghum and to a lesser extent of these insects as pests. on wheat. Growers must monitor their crops for these aphids. Greenbug, Schizaphis graminum (Rondani) Several other cereal aphid species also may be present, but they seldom cause significant damage. Accurate aphid identi- The greenbug is a light green aphid with a dark green fication is necessary to make the best management decisions.
  • Effects of Nitrogen Fertilization on the Life History of the Madeira Mealybug

    Effects of Nitrogen Fertilization on the Life History of the Madeira Mealybug

    Clemson University TigerPrints All Theses Theses 12-2015 Effects of Nitrogen Fertilization on the Life History of the Madeira Mealybug (Phenacoccus madeirensis) and the Molecular Composition of its Host Plant Stephanie Alliene Rhodes Clemson University Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Recommended Citation Rhodes, Stephanie Alliene, "Effects of Nitrogen Fertilization on the Life History of the Madeira Mealybug (Phenacoccus madeirensis) and the Molecular Composition of its Host Plant" (2015). All Theses. 2584. https://tigerprints.clemson.edu/all_theses/2584 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. EFFECTS OF NITROGEN FERTILIZATION ON THE LIFE HISTORY OF THE MADEIRA MEALYBUG (PHENACOCCUS MADEIRENSIS) AND THE MOLECULAR COMPOSITION OF ITS HOST PLANT A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Entomology by Stephanie Alliene Rhodes December 2015 Accepted by: Dr. Juang-Horng Chong, Committee Co-Chair Dr .Matthew Turnbull, Committee Co-Chair Dr. Peter Adler Dr. Dara Park ABSTRACT The aim of this study was to investigate how different nitrogen fertilization rates of host-plants influence the development, fecundity, and nutritional status of a pest insect, the Madeira mealybug (Phenococcus madeirensis Green, Hemiptera: Psuedococcidae). This study evaluated the effects of nitrogen fertilization (0, 75, 150 and 300 ppm N) on the growth, % nitrogen, % carbon, lipid, and protein contents of basil plants (Ocimum basilicum L., Lamiaceae), and the subsequent impacts of host-plant nutritional status on the life history and total lipid and protein contents of the Madeira mealybug.
  • The Russian Wheat Aphid in Utah

    The Russian Wheat Aphid in Utah

    Extension Entomology Department of Biology, Logan, UT 84322 Utah State University Extension Fact Sheet No. 80 February 1993 THE RUSSIAN WHEAT APHID IN UTAH Introduction Since arriving in Utah in 1987, the Russian wheat aphid, Diuraphis noxia (Kurdjumov), has spread to all grain growing areas of the state. It is very unpredictable in that at times it becomes an economic pest and at other times it is just present. In some areas it has caused losses in wheat and barley of up to 50 percent or more. It can be a problem in fall or spring planted grains. Biology Russian wheat aphids infest wheat, barley, and triticale, as well as several wild and cultivated grasses. Broadleaf plants such as alfalfa, clover, potatoes, and sunflowers are not hosts. Volunteer grain plays a key role in the life cycle of this pest by providing a food source in the interval between grain harvest and the emergence of fall-seeded crops. Many species of grasses act as reservoir hosts during the late-summer dry season; however, grasses such as barnyard grass and foxtail grass that grow on irrigation ditch banks and other wet waste areas are poor hosts. Most wild desert grasses are normally dormant and unsuitable for aphids during this period. In some cases, winged forms may feed on corn during heavy flights, but no colonization occurs. In the summer, all Russian wheat aphids are females that do not lay eggs but give birth to live young at a rate of four to five per day for up to four weeks. The new young females can mature in as little as 7-10 days.
  • Aphid Vectors and Grass Hosts of Barley Yellow Dwarf Virus and Cereal Yellow Dwarf Virus in Alabama and Western Florida by Buyun

    Aphid Vectors and Grass Hosts of Barley Yellow Dwarf Virus and Cereal Yellow Dwarf Virus in Alabama and Western Florida by Buyun

    AphidVectorsandGrassHostsofBarleyYellowDwarfVirusandCerealYellow DwarfVirusinAlabamaandWesternFlorida by BuyungAsmaraRatnaHadi AdissertationsubmittedtotheGraduateFacultyof AuburnUniversity inpartialfulfillmentofthe requirementsfortheDegreeof DoctorofPhilosophy Auburn,Alabama December18,2009 Keywords:barleyyellowdwarf,cerealyellowdwarf,aphids,virusvectors,virushosts, Rhopalosiphumpadi , Rhopalosiphumrufiabdominale Copyright2009byBuyungAsmaraRatnaHadi Approvedby KathyFlanders,Co-Chair,AssociateProfessorofEntomologyandPlantPathology KiraBowen,Co-Chair,ProfessorofEntomologyandPlantPathology JohnMurphy,ProfessorofEntomologyandPlantPathology Abstract Yellow Dwarf (YD) is a major disease problem of wheat in Alabama and is estimated to cause yield loss of 21-42 bushels per acre. The disease is caused by a complex of luteoviruses comprising two species and several strains, including Barley yellowdwarfvirus (BYDV),strainPAV,and Cerealyellowdwarfvirus (CYDV),strain RPV. The viruses are exclusively transmitted by aphids. Suction trap data collected between1996and1999inNorthAlabamarecordedthe presence of several species of aphidsthatareknowntobeB/CYDVvectors. Aphidsweresurveyedinthebeginningofplantingseasonsinseveralwheatplots throughout Alabama and western Florida for four consecutive years. Collected aphids wereidentifiedandbioassayedfortheirB/CYDV-infectivity.Thissurveyprogramwas designedtoidentifytheaphid(Hemiptera:Aphididae)speciesthatserveasfallvectorsof B/CYDVintowheatplanting.From2005to2008,birdcherry-oataphid,
  • Molecular Characterization of Cereal Yellow Dwarf Virus-Rpv in Grasses in European Part of Turkey

    Molecular Characterization of Cereal Yellow Dwarf Virus-Rpv in Grasses in European Part of Turkey

    Agriculture (Poľnohospodárstvo), 66, 2020 (4): 161 − 170 Original paper DOI: 10.2478/agri-2020-0015 MOLECULAR CHARACTERIZATION OF CEREAL YELLOW DWARF VIRUS-RPV IN GRASSES IN EUROPEAN PART OF TURKEY Havva IlbağI1*, AHMET Çıtır1, ADNAN KARA1, MERYEM UYSAL2 1Namık Kemal University, Tekirdağ, Turkey 2Selçuk University, Konya,Turkey ılBAğı, H. – Çıtır, a. − KaRa, a. − UYSal, M.: Molecular characterization of cereal yellow dwarf virus-RPv in grasses in european part of Turkey. agriculture (Poľnohospodárstvo), vol. 66, no. 4, pp. 161 – 170. Yellow dwarf viruses (YDvs) are economically destructive viral diseases of cereal crops, which cause the reduction of yield and quality of grains. Cereal yellow dwarf virus-RPV (CYDv-RPv) is one of the most serious virus species of YDvs. These virus diseases cause epidemics in cereal fields in some periods of the year in Turkey depending on potential reservoir natural hosts that play a significant role in epidemiology. This study was conducted to investigate the presence and prevalence of CYDv-RPv in grasses and volunteer cereal host plants including 33 species from Poaceae, asteraceae, Juncaceae, Gerani- aceae, Cyperaceae, and Rubiaceae families in the Trakya region of Turkey. a total of 584 symptomatic grass and volunteer cereal leaf samples exhibiting yellowing, reddening, irregular necrotic patches and dwarfing symptoms were collected from Trakya and tested by ElISa and RT-PCR methods. The screening tests showed that 55 out of 584 grass samples were infect- ed with CYDv-RPv in grasses from the Poaceae family, while none of the other families had no infection. The incidence of CYDv-RPv was detected at a rate of 9.42%.
  • Barley Yellow Dwarf Management in Small Grains

    Barley Yellow Dwarf Management in Small Grains

    Barley Yellow Dwarf Management in Small Grains Nathan Kleczewski, Extension Plant Pathologist September 2016 Bill Cissel, Extension IPM Agent Joanne Whalen, Extension IPM Specialist Overview Barley Yellow Dwarf (BYD) was first described in 1951 and now is considered to be the most widespread vi- ral disease of economically important grasses worldwide. This complex, insect-vectored disease can have con- siderable impacts on small grain yield and quality and may be encountered by growers in Delaware. This fact- sheet will describe the disease, its vectors, and current management options. Symptoms Symptoms of BYD vary with host species, host resistance level, environment, virus species or strain, and time of infection. The hallmark symp- tom of BYD is the loss of green color of the foli- age, especially in older foliage. In wheat, the foli- age may turn orange to purple (Figure 1). Similar foliar symptoms may occur in barley, except that the foliage may appear bright yellow. In severe cases, stunting can occur and result in a failure of heads to emerge. In other severe cases the heads may contain dark and shriveled grain or not con- tain any grain. Tillering and root masses may also be reduced. BYD is often observed in Delaware in patches 1-5 feet in diameter, however, larger infections have been reported in other states. Symptoms of BYD, as with other viruses, are easy to overlook or confuse with other issues such as nutrient deficiency or compaction. Thus, diagno- sis cannot be confirmed by symptoms alone and Figure 1. Wheat showing characteristic foliar symptoms samples must be sent to diagnostic labs for confir- of BYD virus infection.
  • Identifying Aphid Resistance in the Ancestral Wheat Triticum Monococcum Under Feld Conditions Amma L

    Identifying Aphid Resistance in the Ancestral Wheat Triticum Monococcum Under Feld Conditions Amma L

    www.nature.com/scientificreports OPEN Identifying aphid resistance in the ancestral wheat Triticum monococcum under feld conditions Amma L. Simon1,2*, John C. Caulfeld1, Kim E. Hammond‑Kosack1, Linda M. Field1 & Gudbjorg I. Aradottir3 Wheat is an economically, socially, and nutritionally important crop, however, aphid infestation can often reduce wheat yield through feeding and virus transmission. Through feld phenotyping, we investigated aphid resistance in ancestral wheat Triticum monococcum (L.). Aphid (Rhopalosiphum padi (L.), Sitobion avenae (F.) and Metopolophium dirhodum (Wlk.)) populations and natural enemy presence (parasitised mummifed aphids, ladybird adults and larvae and lacewing eggs and larvae) on two naturally susceptible wheat varieties, Triticum aestivum (L.) var. Solstice and T. monococcum MDR037, and three potentially resistant genotypes T. monococcum MDR657, MDR045 and MDR049 were monitored across three years of feld trials. Triticum monococcum MDR045 and MDR049 had smaller aphid populations, whereas MDR657 showed no resistance. Overall, natural enemy presence was positively correlated with aphid populations; however, MDR049 had similar natural enemy presence to MDR037 which is susceptible to aphid infestation. It is hypothesised that alongside reducing aphid population growth, MDR049 also confers indirect resistance by attracting natural enemies. The observed resistance to aphids in MDR045 and MDR049 has strong potential for introgression into commercial wheat varieties, which could have an important role in Integrated Pest Management strategies to reduce aphid populations and virus transmission. Wheat Triticum aestivum (L.) is the third most important crop globally and is the main ingredient in many diets worldwide1,2 providing 20–29% of dietary calories and protein 3. In Europe, wheat is the main crop with 138.3 million tonnes produced in 2018 (FAO, 2020).
  • Barley Yellow Dwarf Virus Aphids in Wheat

    Barley Yellow Dwarf Virus Aphids in Wheat

    W 389 Clay Perkins, Graduate Research Assistant Scott Stewart, Professor Heather Kelly, Assistant Professor Department of Entomology and Plant Pathology BARLEY YELLOW DWARF VIRUS Symptoms Barley yellow dwarf (BYD) is one of the most detrimental viral infections of small grains, including wheat. Seven viruses are currently known to cause the infection. A common symptom of BYD is stunting due to reduced internode length, and this is particularly apparent when infection occurs during the seedling stage. Stunting of plants can be so severe that no heads are produced or so mild that it is hard to recognize. Another conspicuous symptom of BYD is the discoloration of leaves. The leaves lose their green color and turn yellow and/or have a pink or reddish color, especially at their tips as seen in the photo above. Diagnosis may be complicated as there are many other causes Courtesy of Oklahoma State University and USDA ARS, of leaf yellowing. The presence of pink to reddish leaf tips is a Stillwater, OK. more consistent indicator of BYD. In addition, the fuse of the enzyme-linked immunosorbent assay (ELISA) has proven to be an efficient way to confirm infection. Aphids are small, soft-bodied insects. They have sucking mouthparts used to puncture the plant tissue to feed on How It Spreads the phloem (sap) of plants. These aphids have varying and BYD is vectored by aphids and can infect over 150 species of sometimes complex life cycles, but in wheat, they reproduce grasses. Aphids acquire the virus by feeding on an infected host. asexually and give birth to live young rather than laying eggs.