Mixed infections of cucumber fruits caused by diverse fungal pathogens under greenhouse conditions

Cucumber is among the most widely cultivated crops in greenhouses conditions in Kyrgyzstan. In recent years, parthenocarpic heterotic hybrids have become common in greenhouse production. However, the resistance or susceptibility of these hybrid varieties to fungal and bacterial diseases remains largely unexplored. This is a significant concern, as greenhouses create optimal conditions for pathogens due to elevated humidity and restricted airflow. Accurate and timely diagnosis of cucumber diseases is crucial for effective crop protection. Nonetheless, in Kyrgyzstan, the pathogens affecting cucumbers grown both in open fields and greenhouses have yet to be examined using specialised phytopathological methods to determine their unique morphophysiological and pathogenic characteristics. This study aimed to isolate and identify the main fungal pathogens affecting greenhouse-grown Björn F1 cucumbers and to evaluate their pathogenicity. Cucumber fruits displaying disease symptoms were collected for analysis. Both modern and classical phytopathological and microbiological techniques were employed to identify the pathogens, while their cultural and morphological traits were examined using light microscopy. The study identified fungal diseases in greenhouse-grown cucumbers caused by pathogens from the genera Fusarium, Botrytis, Alternaria, and Cladosporium. Pathogenicity tests were performed both in vitro and in vivo. The relative prevalence of each genus was as follows: Fusarium spp. (25%), Botrytis spp. (30%), Alternaria spp. (15%), and Cladosporium spp. (30%). Notably, the imported cucumber variety Björn F1 exhibited considerable susceptibility to multiple pathogens affecting both fruits and other plant organs. Furthermore, synergistic infections – where several pathogenic species simultaneously attacked a single plant – were observed, highlighting the need for integrated and targeted protective measures