Clerodendrum begomovirus

Clerodendrum begomovirus is a plant pathogen belonging to the genus Begomovirus within the family Geminiviridae. This virus possesses a circular single-stranded DNA genome and is primarily known for causing systemic yellow mosaic symptoms. It disrupts the plant's physiological processes, leading to significant economic loss in ornamental nurseries.

The host range is mainly focused on the Clerodendrum genus, a popular ornamental plant species. However, the virus can also persist in other related ornamental plants and weeds, making management challenging. Once a plant is infected, the virus spreads systemically through the phloem, affecting all new growth.

Symptoms typically manifest as intense golden or yellow mosaic patterns on the foliage. Affected leaves often exhibit curling, crinkling, and significant size reduction. In severe cases, the infected plants show stunted growth, reduced floral development, and early senescence, which renders them aesthetically unmarketable.

The transmission of this virus is exclusively through the whitefly (Bemisia tabaci) in a persistent, circulative manner. The vector acquires the virus by feeding on the phloem sap of an infected host and can transmit it for the remainder of its lifespan. Warm and humid greenhouse conditions create the perfect environment for whitefly proliferation and subsequent viral outbreaks.

Management of the disease relies entirely on prevention and vector control as there is no cure for established viral infections:

• Strict insecticidal control of the whitefly population.
• Use of fine-mesh screening in greenhouses to exclude vectors.
• Immediate removal and destruction of infected symptomatic plants.
• Regular inspection of incoming stock during the quarantine phase.
• Maintaining greenhouse sanitation and weeding surrounding areas.