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

Abstract

ABSTRACT

Objective:

Design/methodology/approach: Due to the suspension of the chile tabaquero planting and harvesting season in 2022, a chile habanero plantation with similar symptoms to those observed in chile tabaquero was identified for pathogen isolation. The morphological and pathogenic characterization of the fungus associated with these lesions, as well as 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 show that the fungus belonging to the genus Colletotrichum, specifically the species C. truncatum (without C. capsici) may be the causal agent that caused fruit and leaf necrosis in the tobacco chili plantations of Macuspana Tabasco, in the year 2021-22, so this research provides relevant information for the development of effective management strategies and phytosanitary control in the current plantations.

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Limitations on study/implications: The infrastructure conditions and climatic variables within the greenhouse may have influenced the parameters obtained during the study. Additionally, the complete molecular identification of the selected fungi at the species level was limited by the high costs associated with this process.

Findings/conclusions: Pathogenicity tests and the expression of symptoms in chile bell pepper fruits show that the fungus Collecotrichum truncatum can be the causal agent of fruit anthracnose and leaf spot in tobacco chile plantations in the municipality of Macuspana, Tabasco, Mex.

However, the need to implement more precise diagnostic techniques, such as microscopy and molecular analysis, to identify the presence of the fungus in early stages of infection is emphasized. This would not only help to improve phytosanitary controls, but would also allow the design of integrated management strategies to reduce the spread of the pathogen in agricultural crops of high commercial value.

Keywords: Colletotrichum, Koch’s postulates, Pathogenicity, Molecular, Fungus.