Isolation and identification of microorganisms associated with late blight disease of tomato (Solanum lycopersicum L.) in Niger State, Nigeria

Abstract

Late blight disease remains one of the major constraints affecting tomato production worldwide due to its rapid spread and destructive effects on infected plants. This study was undertaken to isolate and identify microorganisms associated with late blight disease of tomato plant in Niger state. A total of thirty diseased tomato samples showing symptoms of late blight were collected from selected tomato farmlands from Bida, Lapai and Agaie Local Government Area of Niger State, Nigeria. The samples were analyzed using standard microbiological and biochemical techniques. Fungal isolates were identified based on their cultural and microscopic characteristics, while bacterial isolates were identified using biochemical tests. The fungi isolated included Phytophthora infestans (40.0%), Alternaria solani (25.3%), Fusarium oxysporum (18.7%), Aspergillus flavus (10.7%), and Phoma destructiva (5.3%). The bacterial isolates recovered were Pseudomonas syringae (38.5%), Xanthomonas campestris (30.8%), Ralstonia solanacearum (20.5%), and Bacillus subtilis (10.2%). Phytophthora infestans and Pseudomonas syringae were the most predominant fungal and bacterial isolates, respectively. The findings of this study indicate that late blight-infected tomato plants harbor diverse fungal and bacterial species that may collectively contribute to disease severity and tissue deterioration. The study therefore emphasizes the importance of accurate identification of microorganisms associated with tomato diseases for effective disease monitoring and management in tomato production.