Desmodium golden mosaic virus

Pathogen and disease type. The pathogen is Begomovirus desmodii, a member of the genus Begomovirus within the Geminiviridae family. It is a viral disease characterized by a circular single-stranded DNA genome. The virus systemically infects plant tissues, causing significant physiological disruptions that affect the overall health and productivity of the host.

Host range. The primary host is the wild legume genus Desmodium. However, this virus poses a substantial risk to agricultural legume crops such as common beans and soybeans. When these crops are cultivated near wild vegetation containing the virus, the likelihood of transmission increases significantly, potentially leading to outbreaks in agricultural fields.

Symptoms and signs. The name "golden mosaic" describes the most prominent symptoms: the appearance of striking yellow or golden chlorotic patches on the leaves. Infected plants often show stunted growth, crinkled or distorted foliage, and shortened internodes. The systemic nature of the infection typically leads to reduced biomass and impaired seed development in affected plants.

Development and spread. The virus is transmitted in a persistent, circulative manner by the whitefly Bemisia tabaci. The spread of the disease is highly correlated with the presence and population density of the whitefly vector. Environmental conditions, particularly high temperatures and humidity, favor the proliferation of whiteflies and the subsequent rapid transmission of the virus across the field.

Control and prevention. Management of Begomovirus desmodii focuses on an integrated approach since there is no direct chemical cure for infected plants:

• Strict control of whitefly populations using systematic insecticides.
• Removal of weed reservoirs that may harbor the virus.
• Implementation of crop rotation to break the infection cycle.
• Use of virus-resistant or tolerant crop varieties.
• Spatial isolation from infected wild legume habitats.