Paprika mild mottle virus

The virus consists of rod-shaped particles containing single-stranded RNA. It is considered one of the most aggressive pathogens affecting solanaceous crops, especially under intensive greenhouse conditions.

Its taxonomy is closely related to other Tobamoviruses, such as Tobacco mosaic virus (TMV) and Tomato mosaic virus (ToMV). These viruses share similar transmission mechanisms and high survival rates in the environment.

Transmission occurs primarily through mechanical means: via contaminated tools, foliage contact, personnel hands or clothing, and through infected seeds or soil residues.

The biology of PMMoV is notable for its stability against high temperatures and pH fluctuations. The virus survives well in dry plant tissues, which makes greenhouse management particularly challenging.

The primary host is sweet pepper, although the virus can also infect tomatoes and other Capsicum species. Economic damage results in a significant reduction in fruit quality and total yield.

Infected plants exhibit stunted growth, resulting in dwarfism. Leaves become deformed and wrinkled, which severely disrupts the photosynthesis process.

Fruits affected by the virus often show atypical coloration, spotting, or necrotic lesions. This reduction in quality makes the produce unmarketable in commercial retail channels.

Early infection in seedlings can lead to complete plant collapse or permanent sterility. Yield losses can range between 50% and 80% in high-pressure environments.

The spread of the virus within greenhouse complexes is rapid due to high plant density and the frequent contact involved in pruning and harvesting operations.

The primary symptom is a mosaic pattern on the leaves, characterized by alternating light-green and dark-green areas. Over time, this mosaic progresses into severe leaf curling.

Chlorosis and abnormal development of young shoots are hallmark signs. Apical growth may twist, and internodes become shortened, giving the plant a stunted, bushy appearance.

Fruits often develop sunken spots that darken over time. Internal fruit tissues may soften, potentially leading to secondary fungal or bacterial rots.

Root system development is inhibited during viral infection, which further increases the plant's susceptibility to nutrient deficiencies and environmental stress factors.

• Vein yellowing
• Leaf distortion
• Fruit spotting
• Growth stunting
• Flower and fruit drop

There are no chemical treatments available to cure plants infected with Paprika mild mottle virus. Therefore, agronomic efforts must prioritize strict prevention to exclude the pathogen from the production cycle.

The use of certified, virus-free seed is mandatory. It is essential to treat seeds prior to sowing using thermal or chemical disinfection methods to eliminate potential surface contamination.

Strict sanitation protocols must be enforced: disinfecting tools after contact with each plant, and requiring personnel to wash hands with soap or sanitizers. Tools should be dipped in disinfectant solutions regularly.

At the end of the season, full greenhouse sanitation is required, including the removal of all crop debris, disinfection of structures and equipment, and soil sterilization or replacement.

Implementing resistant hybrids is the most effective management strategy. Regular monitoring of the crop helps to identify infection hotspots early, allowing for the immediate isolation and removal of symptomatic plants.