Bean Pod Mottle Virus
Bean pod mottle virus (BPMV)
is a virus disease found throughout Iowa in soybeans and other legumes.
There are two potential problems with bean pod mottle virus: reduction
in soybean quality and yield loss.
Symptoms of infection by bean
pod mottle virus are most apparent during periods of cool weather and
when the plant is actively growing. Infected soybean plants may have
mottled or crinkled leaves and plants may be stunted.
Symptoms
may resemble injury from herbicide drift or symptoms of other soybean
viruses. As soybeans mature, foliar symptoms are less apparent. Infected
plants may have mottled or discolored seed at harvest (Figure 1). Delayed
maturity of stems and leaves ("green stem") may also occur
in BPMV-infected plants.
There are two potential
problems with bean pod mottle virus: reductions in soybean quality and
reductions in yield. The effect of bean pod mottle virus on yield has
been shown to vary by soybean variety and growing conditions. Over a
broad geographic range, yield reductions between 10% and 40% have been
reported.The impact of BPMV on yield depends upon the
time of virus infection; the earlier the soybean is infected with
virus, the greater the effect on yield and seed quality.
Another problem
with BPMV is that a synergistic reaction occurs when plants are infected
with both BPMV and soybean mosaic virus. Reduction in yield is much
greater in mixed infections than either virus alone.
Most plant viruses
are spread from plant to plant by specific insect vectors. In the case
of BPMV, the bean leaf beetle, spreads the virus from plant to plant as it feeds.
In addition to soybean, showy tick trefoil, a native host for
bean leaf beetles, can carry the virus. BPMV can also be seedborne.
Management of
Bean Pod Mottle Virus
It's important
to establish a field history of BPMV before deciding on management options.
Factors that indicate a field history of BPMV are:
• a significant yield reduction in the previous year
• mottled or discolored seed and/or seed test indicated
presence of BPMV
• delayed maturity in some plants - "green stem syndrome"
• large bean leaf beetle populations in the fall
There are no known
commercial soybean varieties with resistance to bean leaf beetles or
bean pod mottle virus. The short-term management options available for
growers at this time are carefully-timed soybean planting and insecticide
application for early-season bean leaf beetle control. Do not plant
mottled or discolored seed from fields which had a high level infestation
of bean leaf beetle.
Bean pod mottle virus is back in Iowa in 2006 and the populations of bean leaf beetles seems to be the worst we have seen since 2002. See the recent update on bean pod mottle virus and what we can expect during the harvest of 2006.
A good summary of
management of BPMV in Iowa
can be found in this article in the Integrated Crop Management
newsletter:
Management
decisions for bean leaf beetles and bean pod mottle virus (May 2005).
Bean
pod mottle virus. A threat to U.S. soybean production. Giesler,
L. J., Ghabrial, S. A., Hunt, T. E., and Hill, J. H. 2002. Plant Disease 86:1280-1289. (link to PDF file).
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