Diagnosis of the causal agent of fruit necrosis in tabaquero pepper (Capsicum annuum L.)

Resumen

Objective: To identify the causal agent of fruit necrosis in tabaquero pepper (Capsicum annuum).

Design/methodology/approach:
Since the planting and harvesting season of tabaquero pepper was suspended in 2022, a habanero pepper plantation exhibiting symptoms similar to those observed in tabaquero pepper was selected for pathogen isolation. Morphological and pathogenic characterization of the fungus associated with these lesions, as well as with foliar spots on the plants, was carried out. Additionally, molecular identification techniques using the 18S molecular marker were implemented to confirm the causal agent of anthracnose in this crop.

Results:
The results indicate that the fungus belonging to the genus Colletotrichum, specifically the species C. truncatum (syn. C. capsici), may be the causal agent responsible for fruit and leaf necrosis in tabaquero pepper plantations in Macuspana, Tabasco, during the 2021–2022 season. Therefore, this research provides relevant information for the development of effective phytosanitary management and control strategies in current plantations.

Study limitations/implications:
Greenhouse infrastructure conditions and climatic variables may have influenced the parameters obtained during the study. Additionally, the complete molecular identification of the selected fungi at the species level was limited due to the high costs associated with this process.

Findings/conclusions:
Pathogenicity tests and the expression of symptoms in pepper fruits indicate that the fungus Colletotrichum truncatum may be the causal agent of fruit anthracnose and leaf spot in tabaquero pepper plantations in the municipality of Macuspana, Tabasco, Mexico. However, the need to implement more precise diagnostic techniques, such as microscopy and molecular analyses, is emphasized in order to detect the presence of the fungus at early stages of infection. This would not only improve phytosanitary control measures but also support the design of integrated management strategies aimed at reducing the spread of the pathogen in high-value commercial crops.