Cucumber mosaic virus in snap beans: Symptoms, vectors …

Cucumber mosaic virus in snap beans: Symptoms, vectors and management

Brian A. NaultProfessor

Department of EntomologyCornell University

New York State Agricultural Experiment StationGeneva, NY

Last updated January 2016

Viruses Detected in Snap Bean Fields in Midwestern and Northeastern US Since 2000

• Cucumber mosaic virus (CMV)• Alfalfa mosaic virus (AMV)• Bean common mosaic virus (BCMV)• Bean yellow mosaic virus (BYMV)• Clover yellow vein virus (C1YVV)• White clover mosaic virus (WCMV)• Clover yellow mosaic virus (C1YMV)• Bean pod mottle virus (BPMV)• Tobacco streak virus (TSV)

Grau et al. (2002); Larsen et al. (2002); Shah et al. (2006)

Viruses Detected in Snap Bean Fields in Midwestern and Northeastern US Since 2000



* Implicated in causing yield loss in these regions

Most Common Virus in Snap Bean Fields in Midwestern and Northeastern US Since 2000



CMV Transmission• Primarily transmitted by aphids in a non-persistent, stylet-borne manner1

- Acquired and transmitted within seconds - Multiple plants can be infected, including non- crop plants

1 Nault, L. R. (1997). Ann. Entmol. Soc. Am. 90: 521-541.

Phloem

Hindgut

ASGPSGMidgut

FoodCanal or Stylet

SalivaryCanal

Haemocoel

virus

What Aphid Species are Spreading CMV in Snap Bean Fields?

Sampling Aphids• 5-year study• 5 to 9 traps/ field

• n = 56 fields

• Sampled weekly

• Aphids identified by Dr. Randi Eckel (RTWE Consulting)

ceramic tile on bottom+

propylene glycol + water

Most Common Aphid Species Captured in NY Snap Bean Fields (2002-2006)

Pea aphid(Acyrthosiphon pisum)

Corn leaf aphid(Rhopalosiphum maidis)

#3 (14.8%) #4 (9.2%)

Yellow clover aphid(Therioaphis trifolii)

Soybean aphid(Aphis glycines)

#1 (30.4%) #2 (19.7%)

Nault et al. (2009)

Total number of species= 90; Total number of aphids= 7,484

Most Common Aphid Species Captured in NY Snap Bean Fields (2002-2006)

Yellow clover aphid(Therioaphis trifolii)

Soybean aphid(Aphis glycines)

#1 (30.4%) #2 (19.7%)

Nault et al. (2009)

* Most highly associated with CMV epidemics

Soybean AphidFirst Detected in NY in 2001 (Losey et al. 2002)

NY Soybean Acres Harvested 1978-2009

Soybean aphid arrives

Soybean Aphid Overwintering Range

BuckthornRhamnus spp.

SoybeanGlycine max

Soybean Aphid has Two Hosts

Note: Snap bean, alfalfa and clover are not suitable hosts

Adapted from D. Voegtlin


Soybean Aphid Eggs on Buckthorn

Winter


Soybean Aphid Eggs Hatching on Buckthorn

Spring

Amanda Bachmann, PSU


Soybean Aphid Populations Build on Soybean Summer

Early Late

“Bugs that irk city-dwellers horrify farmers; a field can hold billions”Canadian PressAugust 4, 2001

Baseball game in Toronto Skydome stopped in 3rd inning to close roof!


Soybean Aphid Return to Buckthorn

Soybean Buckthorn

Soybean is not considered a common host for CMVWhere do soybean aphids acquire CMV?

Alfalfa is a Major Host for CMV

• 13 to 18% of alfalfa plants infected with CMV in NY (Shah et al. 2006)

• Number of infected plants estimated @ 22,000 to 31,000/acre

• > 575,000 acres of alfalfa (>17-fold more acreage than snaps); concentrated in western NY

• Perennial (4 to 6 year rotation)• Neither alfalfa nor snap bean are good hosts

for soybean aphid

soybean alfalfa

snap bean

CMV (-)

CMV (+)

Expected Sequence of Events

Soybean aphid

buckthorn

Questions

1. When during the season do soybean aphids fly into snap bean fields?

2. What years will soybean aphids be a problem?

3. How can soybean aphids and/ or CMV be managed in snap bean?

Predicted Soybean Aphid Dispersal Activity in New York Snap Bean Fields (2002-2006)

Predicted Aphid Dispersal Activity in New York Snap Bean Fields (2002-2006)

Planting

Impact of Timing of Virus Infection on Yield

• Infection during early plant development will cause greater losses in yield compared with infection during late developmental stages (Walkey 1991)

0 15 30 45 60 Days after Planting

emergence vegetative stages

bloom pin pod stage

Greater yieldloss

Lower yieldloss

Snap Bean

infection infection

N = 4 fields/year

Mean % CMV in Early-Planted New York Snap Bean Fields (2005-2006)

}

Early Planting Harvest

N = 4 fields/year

Mean % CMV in Mid Season-Planted New York Snap Bean Fields (2004-2006)

}Mid Planting Harvest

N = 4 fields/year

Mean % CMV in Late Season-Planted New York Snap Bean Fields (2004-2006)

Late Planting Harvest

}

Risk Model for Yield Loss from CMV in New York Snap Bean Fields

Low Risk High Risk

Planting

Risk Model for Yield Loss from CMV in New York Snap Bean Fields

Low Risk High Risk

Planting

Could the Risk Line Shift Earlier in the Season in Some Years?

Low Risk High Risk

Planting

?

?

? ?

soybean alfalfa

snap bean

CMV (-)

CMV (+)

Expected Sequence of Events

Soybean aphid

buckthorn???

buckthorn

?

Questions




Soybean Aphid – Every other year phenomenon during first decade

Predictable based on:

- Adults caught in suction traps in Fall (Sept. and Oct)

- Eggs deposited on buckthorn in Fall

Can Soybean Aphid Abundance be Predicted Based on Fall Suction Trap Capture?

2001 ? 2002 75 2003 10 2004 195 2005 30 2006 195 2007 2 2008 152 2009 ?

Year

IllinoisAvg. Soybean Aphid

Capture/ Trap (Sept + Oct)

http://www.ncipmc.org/traps/index.cfm.

North Central Regional Soybean Aphid Suction Trap Network

Questions




Managing Aphid-Transmitted Viruses/ Aphids (1 of 2)

Ineffective or Non-practical solutions• Insecticides (e.g., foliar sprays or seed treatments)• Biological control of aphids • Preventing aphids from landing on crop

- reflective mulches (e.g., tomato and pepper) - row covers

• Interfering with aphid’s ability to transmit virus - mineral and stylet oils (e.g., tomato and pepper)

• Manipulating immigrating aphid populations - border crop or barrier crop

• Separating crop from virus source - distance and time

Managing Aphid-Transmitted Viruses/ Aphids (2 of 2)

Effective solutions ✓ Cultivars resistant to virus (e.g., traditional breeding

or genetically modified)✓ Cultivars tolerant to virus

Hystyle CMV R28 CMVC37/C39

Classical Breeding for CMV ResistanceP. Griffiths, Cornell University

Screening for CMV Tolerance in Snap Bean Cultivars

Jim Ballerstein & Steve ReinersDept. of HorticultureCornell University

Current Management of CMV in Snap Beans

• Plant cultivars that yield well regardless if they are infected with CMV- Tolerant to virus

- High yielding even when infected with virus

• This strategy has been adopted by the processing snap bean industry throughout Great Lakes region (e.g., ‘Huntington’, ‘Summit’ )

Conclusions• Soybean aphid is likely the most important vector of CMV in snap bean fields

• Snap beans planted beyond late June are at highest risk for yield-reducing levels of CMV

• CMV epidemics during odd-numbered years in NY appear to be associated with soybean aphid population dynamics

• Until CMV-resistant cultivars are available, CMV-tolerant cultivars could be planted during last half of season to minimize risk of yield loss

The Bean Virus “Bug” TeamCollaborators at Cornell:➢Drs. Denis Shah, Helene Dillard and Marc Fuchs (PP&PMB)➢Drs. Phil Griffiths, Steve Reiners and Alan Taylor (Horticultural

Sciences)➢Dr. Julie Kikkert (CCE) and Keith Waldron (IPM)

Technical Assistance:➢Katie Straight, Mary Lou Hessney and students (Entomology)➢ Joe Shail and Jim Ballerstein (Horticultural Sciences)

Industry Assistance:➢Roger Ward (Farm Fresh First, Oakfield, NY)➢ Jeff Johnson (Seneca, Geneva, NY)

Funding:➢NYVRC/A and NYFVI

Questions?

Brian A. NaultDepartment of EntomologyCornell University - NYSAESGeneva, NY 14456

[email protected]

Documents

Cucumber mosaic virus in snap beans: Symptoms, vectors …