A fungus detected for the first time in Costa Rica and Central America may affect strawberry production, according to researchers from the National University. The pathogen, Neopestalotiopsis rosae, causes crown rot and progressive wilt and can kill plants. Researchers identified the fungus in strawberry plantations in the provinces of Alajuela, Cartago, and San José.
José Calvo, coordinator of the Phytopathology Laboratory at the university's School of Agricultural Sciences, described the symptoms observed in affected fields. Plants show yellow edges on leaves, circular spots, tissue death, darkened crowns, and progressive wilting that leads to plant collapse.
In recently planted fields, the disease has already been observed in close to 25 per cent of plants. In the United States and Mexico, where the pathogen was previously reported, losses exceeded 40 per cent in affected production areas.
Calvo and colleague Abelardo Arroyo Vargas confirmed the pathogen using molecular analysis. Genes tef1 and tub2 were amplified from plant samples and matched at 99.9 per cent with reference sequences in GenBank. Phylogenetic analysis supported the identification. Researchers then infected healthy strawberry plants, reproduced the same symptoms observed in the field, and re-isolated the fungus, meeting Koch's postulates.
The pathogen survives in plant residues and can also live as a saprophyte on decaying organic matter. Researchers note that it may adapt to other crops, including blueberries, mangoes, and ornamental species.
Strawberry production in Costa Rica takes place throughout the year, mainly in small highland farms supplying the domestic market. Prior to the identification of the pathogen, growers had associated the observed symptoms with other production issues.
At present, no chemical products are registered in Costa Rica for controlling the disease. Calvo recommends biological approaches for management. Growers may apply beneficial microorganisms such as Trichoderma fungi and bacteria from the Pseudomonas and Bacillus groups. These microorganisms suppress the pathogen, support plant development, and contribute to soil microbiota.
Removing crop residues after harvest is also recommended to reduce the spread of the fungus in production areas.
The National University is coordinating with the Agriculture Ministry's Phytosanitary Service on response measures. Planned actions include training workshops for technicians and growers focused on disease monitoring and management.
Calvo emphasised the role of early detection and preventive practices in limiting production losses and maintaining crop output.
Source: The Tico Times
