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					           Status of Virus
            and Virus-like
             Problems on
       Processing Beans
in Wisconsin During 2000
             Craig R. Grau
            Ana Mondjana
         Walter R. Stevenson
   University of WI- Plant Pathology
            Description of Field
             Situation in 2000
• Problematic fields near Belgium and Cambria,
  Wisconsin
• High incidence of plants with virus-like
  symptoms
• Randomly distributed symptoms in the field
• Many fields exhibiting these symptoms were
  destroyed prior to harvest
             Description of Field
              Situation in 2000
• Symptoms observed in the field:

  – Pod distortion
  – Affected pods had a dark brown discoloration
    internally
  – Leaf distortion
  – Mottling and mosaic patterns
 Symptoms observed at Cambria
• Leaf mottling and mosaic

• Internal pod discoloration

• Pod necrosis
Leaf mosaic and
necrosis, Cambria
Leaf mosaic
at Cambria
Rugosity at
Cambria
Leaf mosaic at
Cambria
Pod necrosis at
Cambria
Deformed pods
from Cambria
  Symptoms observed at Belgium
• Leaf mottling and mosaic

• Internal pod discoloration

• Pod necrosis
Mottling on leaves
at Belgium
Leaf mottling at
Belgium
Rugosity and
mottling at Belgium
Leaf rugosity
at Belgium
Pod necrosis
at Belgium
Pod necrosis at Belgium
      Virus Assays Conducted for
           Belgium samples
• Soybean mosaic virus              • Bean yellow mosaic
  (SMV)                               (BYMV)
• Alfalfa mosaic virus              • Tobacco streak virus
  (AMV)                               (TSV)
• Clover yellow vein virus          • Bean common mosaic
  (CYVV)-conducted by Dr.             virus (BCMV)
  Robert Gilbertson, Univ. of CA-
  Davis                             • Bean pod mottle virus
                                      (BPMV)
    Virus Assays Conducted for
         Cambria samples
                        • Alfalfa mosaic virus
Node discoloration at     (AMV)
Cambria

                        • Bean yellow mosaic virus
                          (BYMV)

                        • Tobacco streak virus
                          (TSV)
Viruses Detected in Symptomatic
          Snap Beans

                 Viruses Assayed
          AMV   BCMV     BYVV        CYVV   TSV

                % samples positive
Belgium    85     15         8        100     15
Cambria    67     NA         0        NA       0
      Greenhouse Experiments
• Inoculum from field infected snap beans caused
  similar symptoms on inoculated plants

• Pods provided the best source for virus detection
  and transmission

• Symptoms expressed confirmed by ELISA assay
  for AMV
    Transmission of Stylet-Borne Snap
              Bean Viruses
Clover yellow vein
virus (CYVV)
Bean yellow mosaic
virus (BYMV)           Aphid transmitted
                        Center for IPM; NC State


                          Aphid transmitted


Alfalfa mosaic
virus (AMV)
                       Center for IPM; NC State


                     Aphid and seed transmitted
    Transmission of Stylet-Borne Snap
              Bean Viruses

                   Seed and pollen
Bean common        transmitted
                                                                Center for IPM; NC State


mosaic virus                                                    Aphid transmitted
(BCMV)



Tobacco streak virus   http://newcrop.hort.purdue.edu/rhodcv/
                       hort410/peas/beanfl.jpg


(TSV)
                                                                 Thrips transmitted
  Snap Bean Virus Inoculum
Sources and Insect Transmission
Aphid             AMV, BCMV,
                  CYVV, BYMV


                  AMV, CYVV
Other             BYMV, TSV
Legumes


Seed              AMV, BCMV, TSV
Typical Symptoms for Detected Viruses
 Virus         Leaf       Necrosis              Pod

AMV      Deformed        Mild        Malformed

CYVV     Yellow mosaic   Apical      Severe malformation; wall
                                     discoloration?
BYMV     Yellow mosaic   Apical      Slight malformation

BCMV     Green mosaic    Severe      Wall discoloration

TSV      Dark veins      Red nodes   Malformed , lesions
                     Conclusions
• Alfalfa mosaic virus (AMV), clover yellow vein (CYVV),
  bean common mosaic virus (BCMV), and tobacco streak virus
  (TSV) are associated with symptoms observed in 2000.
• Although AMV was commonly detected, field symptoms were
  more closely associated with symptoms characteristic of clover
  yellow vein (CYVV) and bean common mosaic virus
  (BCMV).
• An aphid transmitted complex of viruses are present and merit
  further investigation.
    Proposed Further Research
• Field survey of snap beans and other legumes for
  types and frequency of viruses.

• Determine whether viruses in snap beans are
  common to other legumes.
    Proposed Further Research
• Evaluate snap beans cultivars and germplasm for
  reaction to AMV and CYVV.
• Determine seed transmission of
  detected viruses.
• Determine if viruses are a component of the
  Disease X symptoms in snap beans.

				
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