Alstroemeria necrosis

Alstroemeria necrosis is a viral disease caused by the Alstroemeria necrotic streak virus (AlNSV), a member of the genus Orthotospovirus. This pathogen is a significant threat to floriculture, as it severely affects the growth, health, and market value of plants by disrupting vascular transport and overall physiological stability.

The primary host for this virus is the alstroemeria plant, commonly grown for cut flower production. The virus is capable of persisting in host tissues and can be found in various ornamental species, making it a persistent challenge for commercial greenhouse environments and nurseries that do not practice strict hygiene.

Symptoms of the infection are visible as chlorotic spotting, mosaic patterns, and distinctive necrotic streaks on the leaves. As the virus progresses, lesions develop on the stems, leading to severe bending, distorted flower buds, and a general reduction in plant vigor. Severely affected plants show stunted growth and often fail to produce marketable blooms.

The transmission of the virus is primarily mediated by thrips, such as the Western flower thrips (Frankliniella occidentalis). The virus is acquired by thrips larvae as they feed on infected tissues and is subsequently transmitted to healthy plants. Secondary spread can occur through vegetative propagation using infected stock or by contaminated tools during pruning and harvesting.

Effective management focuses on an integrated approach:

• Regular monitoring and suppression of thrips populations using biological and chemical controls.
• Rigorous sanitation protocols, including the sterilization of cutting tools.
• Quarantine and testing of incoming plant materials for viral pathogens.
• Prompt roguing of symptomatic plants and their safe disposal away from the growing area.
• Management of greenhouse weeds to eliminate potential virus reservoirs.