HPIPM:Bean Common Mosaic Virus
From BugwoodWiki
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Author: Howard F. Schwartz, David H. Gent, Gary D. Franc and Robert M. Harveson
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Identification and Life Cycle
Bean common mosaic virus (BCMV) causes Bean common mosaic of dry bean, and can be a problem when aphids are present and susceptible varieties are grown near infected plants in the field or nearby field. BCMV is not a production problem east of the Rockies, unless seed stocks were contaminated and high populations of aphids exist. The virus can infect few plants beside dry bean. The virus can be transmitted mechanically by plant-to-plant abrasion and equipment. The virus is disseminated among fields by viruliferous aphids, pollen, movement of contaminated seed, and by movement of contaminated equipment between fields.
Plant Response and Damage
BCMV causes a systemic mosaic or darkening (necrosis) in susceptible plants infected by the virus. Symptoms appear as a green to bluish-green mottled or mosaic pattern on leaves which usually exhibit a downward curling or cupping. This mosaic symptom is often associated with and follows the network of leaf veins, which become slightly darker than the areas between the veins. These symptoms are more easily observed by shading the leaf from direct sunlight. Severe, early infection greatly reduces plant vigor and productivity, and increases seed transmission. The black root reaction is a systemic necrosis symptom that occurs in varieties with a specific gene for resistance to BCMV. Varieties with this gene are resistant to all strains of BCMV under most conditions. However, when plants growing at high temperature are infected with BCMV, the hypersensitive black root reaction develops. The systemic necrosis begins with a slight wilting of young leaflets at any stage of plant growth, followed by a browning or blackening of the vascular tissue, and eventually plant death. Discoloration of the water conducting tissue is observed by making a cross sectional cut through stems and pods. Yield losses from BCMV are more severe when infection occurs early in the growing season, and may approach 80%.
Management Approaches
Biological Control
No biological control strategies have been developed for Bean common mosaic.
Cultural Control
Plant certified seed of varieties resistant to BCMV. The BCMV resistant I gene can be overcome by necrotic strains of BCMV. Varieties with this resistance gene should be avoided if possible in the High Plains regions. Adjust equipment to minimize mechanical injury and rubbing of plants.
Chemical Control
Chemical control of the BCMV aphid vector is seldom effective or economical.
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.
