Wheat Streak Mosaic Virus: a Persistent Threat to Wheat Production

Wheat streak mosaic virus: A persistent threat to wheat production

Dr. Mary Burrows Extension Plant Pathology Specialist, Professor Montana State University Bozeman, MT WSMV history • Described by McKinney in 1919 in IL

Mckinney, H. H. 1937. Mosaic diseases of wheat and related cereals. US Department of Agriculture, Circular no. 442. WSMV: Disease triangle

Host

Vector

Pathogen Environment The virus Wheat curl mite (WCM, Aceria tosichella Keifer) • Virus vector – WSMV, Wheat mosaic virus (fm. High plains virus), Triticum mosaic virus • Microscopic eriophyid mite •Protected • Reproduces rapidly • Limited damage on its own • No known chemical controls – Carbofuran, aldicarb

Slide c. Carmen Murphy WSMV: Transmission • Acquisition: 15 min +; Persists 9 d • Unknown latent period • Inoculation access period 15 min to several hours • Not transovarially transmitted • Transmission mechanism is unclear; May be circulative in some species - evidence is not conclusive • Seed transmitted 0.1-2.5% Wheat streak mosaic virus, Triticum mosaic virus, Wheat mosaic virus (fmr. High Plains virus) • TriMV identified in 2006 in KS • HPV (WMoV) identified in 1993; new variants • Infect cereal grains, grassy weeds, volunteer wheat, corn, etc. can harbor viruses and mites • Transmitted by the wheat curl mite

2014, McCone Co, MT Outline

• Overview of regional survey • Contributing factors – Green bridge hosts, planting date • Epidemic risk 2017 • Management Increase in regional virus incidence?

Host

Vector

（New York Times) Pathogen Environment Survey methods: 2008-2010 Semi-weekly updates to SPHDs, SPROs, and diagnosticians % of samples ELISA positive BYDV- CYDV- Year n WSMV HPV TriMV PAV RPV 2008 754 47 19 17 7 2 2009 1013 32 12 20 17 4 2010 704 28 7 11 14 3 Disease prediction • Fellows, H. & Sill, W. H. 1954. A Method of Predicting Wheat Streak Mosaic Epiphytotics. Phytopathology. 44: 487-487. • Burrows, M., C. Thomas, N. McRoberts, R. Bostock, L. Coop, J. Stack. 2015. Distribution of wheat viruses in the Great Plains region, 2008- 2010 and modeling of symptom onset. Plant Dis. (accepted, Feature Article). The ‘green bridge’ Volunteer wheat/ WW grassy weeds

Next year’s crop

Newly planted WW Late-maturing SW

WSS life cycle and damage

The female WSS deposits eggs in the wheat stem R.K.D. Peterson, MSU WSS overwinters as pre-pupae in wheat WSS emerge May to stubble below soil August https://grdc.com.au surface

http://cropwatch.unl.edu/image

Larvae cause girdling of wheat R.K.D. Peterson, MSU stem Larvae feed on Reduced head parenchyma within weight up to 30 % wheat stem

Every unrecovered “Biological hail” stem = 100 % loss of head weight → Volunteer wheat http://cropwatch.unl.edu

mod. c. Uta Stuhr Wheat streak epidemic 2016 in Montana

Widespread hail

Winter Spring

Long extended fall Fall Summer

Timely rains

Lack of inputs

Early planting dates

mod. c. Uta Stuhr Wheat streak mosaic virus samples into the Schutter Diagnostic Laboratory, 2012-2016

Year WSMV samples* 2012 18 2013 3 2014 42 2015 120 2016 376

*Samples submitted for diagnosis

Timely rains promoted volunteer wheat growth in 2015

Percent of normal precipitation in Montana July 2015

Period of normal: 1981-2010 http://www.wrh.noaa.gov/Greatfalls mod. c. Uta Stuhr Havre, Aug 31, 2015

Hank SW, seeded July 27, irrigated 2016 Planting and emergence of WW was ahead of 5y average in 2014 Normal planting date ww Sept 12-Oct 7

120

100

2014 Planted 40

Percent of crop (%) 5yAvg Planted

20 2014 Emerged

5yAvg Emerged 0 3-Sep 13-Sep 23-Sep 3-Oct 13-Oct 23-Oct 2-Nov

Data from NASS crop progress reports Planting and emergence of WW was ahead of 5y average in 2015 Normal planting date ww Sept 12-Oct 7

120

100

60 2015 Planted 5yAvg Planted 40 2015 Emerged Percent of crop (%) 5yAvg Emerged 20

0 3-Sep 13-Sep 23-Sep 3-Oct 13-Oct 23-Oct 2-Nov 12-Nov 22-Nov Data from NASS crop progress reports WSM epidemic potential 2017

NOAA’s National Weather Service report for Montana, October 2016 • “Nine of the last 12 months have had warmer than normal temperatures.” • “Nine of the past 12 months have measured above normal precipitation.”

Percent of normal precipitation in Montana fall 2016 August 2016 September 2016 October 2016

Period of normal: 1981-2010 http://www.wrh.noaa.gov/Greatfalls

mod. c. Uta Stuhr Planting and emergence of WW was ahead of 5y average in 2016 Normal planting date ww Sept 12-Oct 7

120

100

60 2016 Planted 5yAvg Planted 2016 Emerged 40 5yAvg Emerged Percent of crop (%) Percent of crop (%)

0 7-Sep 27-Sep 17-Oct 6-Nov 26-Nov Why do we plant WW so early? 120

100

Mean yield yield (bu/acre) Mean 40

0 Early mid late Timing of planting

Mace PRHN SNMS TAM112 YSTN Mean yield(bu/acre) with three different timing of planting (early: Sept 1, mid: Sept 15, late: Oct 1) on different varieties of winter wheat, Bozeman. mod. c. N. Ranabhat WCM infestation of volunteer wheat, Bozeman

mod. c. N. Ranabhat Management

• Variety selection • Nitrogen management • Water • Acaricides • Crop termination • Encouraging beneficials? WW loses ~15% yield when inoculated at tillering Timing of infection Winter wheat SW loses ~55% yield when inoculated with WSMV at tillering N increases incidence of WSMV

2009

2010 Fertilization increases the probability of transmission in spring wheat (field study)

1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Probability ofWSMV spread 0 26 216 Nitrogen availability (lbs/ac) Virus-induced yield losses increase with increasing soil nitrate availability

No Virus Virus

35 30 * * 25 * 20 15

Wheat Yield Wheat 10

5 0 10 to 18 19 to 25 26 to 60 61 to 111 112 to 207 Nitrogen Availability (Kg/Ha) *=p<0.05 Water stress Charlie Rush, et al. Texas A&M

• WSMV-infected plants have poor root development and lower water use efficiency – Future: use GPS-guided variable irrigation to avoid WSMV-infected wheat

Price, J. A., Workneh, F., Evett, S., Jones, D. C., Arthur, J., and Rush, C. M. 2010. Effects of Wheat streak mosaic virus on root development and water-use efficiency of winter wheat. Plant Dis. 94:766-770. Workneh, F., Price, J. A., Jones, D. C. & Rush, C. M. 2010. Wheat Streak Mosaic: A Classic Case of Plant Disease Impact on Soil Water Content and Crop Water-Use Efficiency. Plant Disease. 94: 771-774. Velandia, M., Rejesus, R. M., Jones, D. C., Price, J. A., Workneh, F. & Rush, C. M. 2010. Economic impact of Wheat streak mosaic virus in the Texas High Plains. Crop Protection. 29: 699-703. Management

• Variety selection • Nitrogen management • Water • Acaricides • Crop termination • Encouraging beneficials? Insecticides/Acaracides: NONE!

Chemical Trade Name Status Carbofuran Furadan 4F Delisted by EPA as of Jan 2010 Clorpyrifos Lorsban Not labelled for WCM, some efficacy in greenhouse but did not prevent spread of WSMV in the field (WCM protected in leaves/whorl) Imidacloprid Gaucho Not labelled for WCM, no efficacy, may increase WCM (Harvey. 1998. J. Agric. Urban Ent. 20:7-10) Thiamethoxam Cruiser Not labelled for WCM, no efficacy Spiromesifen Oberon No efficacy, not labelled for wheat Acaracide trial, greenhouse

n=8/treatment

WCM infestation

18 chemicals Growth rate indicates static, declining or increasing populations

rt •Nt= N0*e Where: – Nt: Final mite number

–N0: Initial mite number – e: Constant (2.718) – t: Time (days) – r: Population growth rate Bars: SE of the mean Chlorpyrifos (1B) (4E) p<0.001

Chlorpyrifos (1B) (Adv.)

Aldicarb (1A)

Lambda‐cyhalothrin (3A)

Zeta‐cypermethrin*S‐cyano methyl (3A)

Methomyl (1A)

Control

‐0.35 ‐0.3 ‐0.25 ‐0.2 ‐0.15 ‐0.1 ‐0.05 0 0.05 0.1

Insecticides WCM population growth rate c. Carmen Murphy Bars: SE of the mean Petroleum distillate p=0.09

Etoxazole (10B)

Hexythiazox (10A)

Bacillus mycoides J

Extract of neem

Control

‐0.15 ‐0.1 ‐0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Biocontrols and growth WCM population growth rate inhibitors c. Carmen Murphy Bars: SE of the mean Potassium salts p=0.002

Neem oil + azadirachtim

Chitosan

Potassium silicate

I.fumosorosea Apopka

Sulfur

Control

‐0.14 ‐0.12 ‐0.1 ‐0.08 ‐0.06 ‐0.04 ‐0.02 0 0.02 0.04 0.06

Organic WCM population growth rate

c. Carmen Murphy Bars: SE of the mean p=0.86

Thiamethoxam 272g AI/ha

Thiamethoxam 205g AI/ha

Control

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09

Seed treatment WCM population growth rate

c. Carmen Murphy • Organophosphate (Group 1B) • Labelled for wheat and brown wheat mite (spider mites) • Active ingredient Chlorpyrifos • One application per season Field experimental design 2013 (and 2014) • Test 10 treatments with 7 replicates • Complete randomized block design • ANOVA with logit transformation • More realistic conditions • Is virus incidence reduced after treatment?

c. Carmen Murphy Wheat streak mosaic virus field incidence, 2013

0.8 Bars: SE of the mean 0.7 p=0.39 0.6 0.5 0.4 incidence 0.3 0.2 WSMV 0.1 0

c. Carmen Murphy Acaricides? • Chlorpyrifos (Lorsban 4E) shows promise in controlling WCM in greenhouse trials when sprayed prior to symptoms • Results under field conditions inconclusive, high variability in virus incidence • Need to consider economic impact on yield and elimination of natural mite predators

NDSU Orkin.com • Mite survival • Tillage and swathing • Grazing • Mite movement Mites survive ~1 week on glyphosate- treated plants (Survival significantly reduced after 3 d in simulated tillage, DNS)

Wosula et al. 2015. J. Econ Entomology Tillage/swathing reduces WCM survival (Stem cutting = stems cut, taped back to plant; No water = drought conditions; Control = adequate water conditions)

Jiang, W., Garrett, K. A., Peterson, D. E., Harvey, T. L., Bowden, R. L., and Fang, L. 2005. The window of risk for emigration of Wheat streak mosaic virus varies with host eradication method. Plant Dis. 89:853-858. Grazing? • Reduces mites, but type of cereal was more important driver of mite numbers; reduces mites, but how fast? – Umina, P. A., Schiffer, M., Parker, P. and Hoffmann, A. A. (2015), Distribution and influence of grazing on wheat curl mites (Aceria tosichella Keifer) within a wheat field. Journal of Applied Entomology. doi: 10.1111/jen.12268 At high populations of mites on a plant, mites are more likely to move

Stressed plants, with lower mite numbers, are less likely to be a mite source

Thomas, J. A., and Hein, G. L. 2003. Influence of volunteer wheat plant condition on movement of the wheat curl mite, Aceria tosichella, in winter wheat. Exp. Appl. Acarol. 31:253-268. Wegulo et al. NE Extn Bull. EC1871 Wegulo et al. NE Extn Bull. EC1871 What effect does alternate host have on epidemic potential?

• Tested three host treatments, CRD, 54 cones, two plants per cone, – Choteau winter wheat, Triticum aestivum – Cheatgrass, Bromus tectorum – Wheat and cheatgrass mixture •Trial 1: 18-6 light cycle at 23ºC day and 12ºC nights • Trial 2: 12-12 light cycle at 18ºC day and 12ºC nights – Wheat curl mites from a greenhouse stock

c. Everet Owen WCM population growth was lower in cheatgrass and wheat-cheatgrass mixtures than wheat alone

Trial 1 Trial 2 Number of Mites Number Number of Mites Number

Weeks Weeks c. Everet Owen Extrapolation of WCM Population Growth

 Rates can help provide estimations on where 10 meter X 10 meter mite populations are/can be at high wheat field concentrations Square unit Square unit containing: containing: 10 wheat plants 10 cheatgrass plants 10 initial mites 10 initial mites 60 weeks 60 weeks 2,202,480 275,310 potential mites potential mites

100% wheat per unit

100% cheatgrass per unit c. Everet Owen Integrated strategies for control

• Understand the role of the pests in their environment • Identify the factors that favor and discourage pest pressure • Management practices in the Northern Great Plains wheat production system – Planting Date – Variety – Seeding rate – Spring and winter wheat

Northern Agricultural Research Center, Havre, Montana

mod. c. Uta Stuhr How do agronomic practices impact disease pressure?

Randomized Complete Block Design with 4 replications

Winter wheat Spring wheat Planting date Early Mid August Mid April Normal Mid September Mid May Late Mid October Mid June Seeding rate Normal 250 plants/ m2 High 500 plants/ m2

Variety Rampart 1, 3 Choteau 2, 3 Yellowstone 0, 4 Duclair 2,3 Judee 2, 3 Gunnison 2,4 MTV1681 ?, 4 Reeder 2,4

0 – WSMV moderately resistant 1 – WSMV tolerant 2 – WSMV susceptible 3 – WSS resistant 4 – WSS susceptible

mod. c. Uta Stuhr Anticipated outcomes • Early planting date WW = increased disease pressure • Later planting date SW = increased disease pressure • More dense seeding rate = increased disease and sawfly • Insecticides cause more harm than good (beneficials) October 1, 2016 November 15, 2016 Other questions

• How do management practices influence beneficial insects, disease and insect pests? – Insecticide: Lorsban, Warrior, Tebufos • How (does) crop rotation influence beneficial insects? – Lentil, barley • Update variety screens, including barley – Does WSMV affect nitrate in hay? – Is WSMV seed transmitted in our varieties?