Plant Disease: Bean Pod Mottle Virus

Taxonomy:

Distribution:

• First identified in Nebraska in 1981.


• Found in most of the soybean producing counties in the state.

Vector:

• The bean leaf beetle most commonly transmits the virus.


• Beetles transmit BPMV efficiently for several days after feeding on an infected plant.


• The virus is transmitted as the beetle regurgitates previously ingested plant material, which has the virus, and it is introduced into the feeding wound.


• The virus is known to increase in concentration in the beetles after continued feeding on infected plants by the beetles.


• The beetle can transmit the virus immediately after acquiring it, but is not able to transfer the virus to its offspring.


• Seed transmission has been documented, but occurs at a very low percentage (0.1% or less).

Impact:

• Documented to reduce yield by as much as 52% in other states.

Symptoms:

• Green to yellow mottling (blotchiness) of younger leaves in the upper canopy.


• In severe cases leaves may show blistering or puckering and distortion and plants can be stunted.

• Pods can be misshapen with mottling and reduced in size.


• Infected plants may have green stems after the pods have matured.


• Seed from infected plants may appear smoky in color or have reduced size and quality due to seed coat mottling which will be brown or black depending on hilum color (also referred to as hilem bleeding).


• The only way to confirm the presence of BPMV is with serological testing (ELISA).

Conditions Favorable for Development:

• Symptoms appear during cool weather.


• Symptom expression may be impeded at high temperatures.


• Bean leaf beetles transmit virus, so weather favorable for their over wintering will increase incidence of this disease.

Host Range:

• The host range of BPMV is restricted primarily to legumes.


• It is thought that some perennial legumes may play a role in the over wintering of the virus.

Management:

• To date BPMV resistance has not been identified, however varieties will respond differently to the virus.


• Avoiding early planting dates can reduce BPMV incidence in areas with a history of high bean leaf beetle populations.


• Other cultural practices such as trap crops have not yet been scientifically evaluated.

Notes: