Okra mosaic virus

Okra mosaic disease is caused by Begomovirus abelsmoschusmaculae, a viral pathogen belonging to the Geminiviridae family. This virus is a major constraint in the cultivation of okra (Abelmoschus esculentus), often causing severe economic losses in tropical and subtropical regions globally by infecting the vascular system of the host plants.

The primary host for this virus is okra, although it can infect a range of other plants in the Malvaceae family. These alternate hosts, including several weeds, serve as crucial reservoirs for the virus during the off-season. Because of this wide host range, the pathogen can quickly establish itself in new areas, making it difficult to eradicate completely.

Symptoms of the disease are typically characterized by a systemic mosaic pattern of light and dark green patches on leaves. Infected plants often show curling, yellowing, and deformation of leaf tissues. Stunting of the entire plant is common, which significantly reduces flower production and causes fruit malformation, rendering the harvest unmarketable.

The transmission of the virus occurs primarily through the whitefly Bemisia tabaci. The insect acts as a vector, acquiring the virus by feeding on infected plant sap and then transmitting it to healthy plants. Outbreaks are most frequent during periods of high whitefly population density, which is often exacerbated by warm, dry weather conditions and inadequate weed management.

Management strategies focus on an integrated pest management approach. Key measures include:

• Utilizing resistant or tolerant crop varieties.
• Rigorous control of the whitefly vector using appropriate insecticides.
• Removal and destruction of infected plants to reduce primary inoculum.
• Effective weed control to eliminate reservoir host plants.
• Implementation of physical barriers like fine-mesh insect screens for nursery crops.