Gloxinia ringspot

Gloxinia ringspot is a viral disease caused by the Impatiens necrotic spot virus (INSV). This pathogen is a significant threat in greenhouse and indoor gardening environments due to its systemic nature and the difficulty of eradicating it once a plant is infected.

The host range of INSV is exceptionally broad, encompassing hundreds of plant species. Besides Gloxinia, the virus frequently infects crops such as impatiens, cyclamen, begonia, and various ornamentals. This diversity of hosts makes the virus particularly difficult to manage in commercial greenhouses where multiple plant species are grown in close proximity.

The symptoms of this disease are quite distinct and often include chlorotic rings, necrotic spots, or line patterns on the leaves. Infected plants may show distorted growth, stunted development, and reduced flowering. In severe cases, the foliage exhibits extensive necrosis, eventually leading to the collapse of the plant.

Transmission of the virus is primarily achieved through insect vectors, with the western flower thrips (Frankliniella occidentalis) being the most common culprit. The insect picks up the virus while feeding on infected plant tissues during its larval stage and remains capable of transmitting the virus for the remainder of its lifespan, facilitating rapid spread within a greenhouse.

There are no chemical treatments available to cure a plant infected with INSV. Therefore, management focuses heavily on prevention and sanitation. Key strategies include:

• Rigorous monitoring and control of thrips populations using insecticides and sticky traps.
• Regular sanitation of tools and working surfaces to avoid mechanical transmission.
• Eliminating weeds in and around the greenhouse that may harbor both the virus and the insect vectors.
• Immediate removal and destruction of infected plant material to protect the remaining collection.