Rhouma1*, I. Ben Salem1, M. Muhamdi2 and N. Boughalleb-M’Hamdi1
(1) Département des Sciences Biologiques et de la Protection des Plantes, Institut Supérieur Agronomique de Chott Mariem, 4042 Sousse, LR21AGR05, University of Sousse, Tunisia, (2) Département des Sciences Horticoles et du Paysage, Institut Supérieur Agronomique de Chott Mariem, 4042 Sousse, University of Sousse, Tunisia.
*Email address of the corresponding author: [email protected]
Received: 29/5/2024; Accepted: 23/8/2024
This investigation examined the effect of organic manure application (20, 40 and 60 tons/ha) on fungal communities in the rhizosphere of cucurbit plants (watermelon, grafted watermelon, melon, grafted melon, and squash) grown under field conditions. Prevalent fungal species were identified as Cladosporium cladosporioides (0.83×105 CFU/g soil) and Alternaria alternata (0.22×105 CFU/g soil). Sclerotinia sclerotiorum, Cladosporium herbarum, Scytalidium thermophilum, and Arthrinium sp. were also consistently detected. Pathogenicity test via artificial inoculation on watermelon leaves in greenhouse revealed that the most virulent pathogens were S. sclerotiorum (SC2) with level of lesion severity reached 80.72%, and A. alternata (Aa2) 73.76%. To assess potential biocontrol agents, 24 soilborne-fungal antagonists were evaluated for their inhibitory activity against six pathogens using direct contact method. Trichoderma harzianum displayed the strongest mycelial growth inhibition rate (48.99-85.42% against various pathogens), followed by Humicola grisea (32.21-80.68%) and Gliocladium catenulatum (26.64-83.66%). Finally, the in vivo efficacy of four fungal antagonists against six pathogens was tested in a randomized complete block design following preventive and curative treatments on watermelon leaves. Both T. harzianum and T. viride significantly reduced disease incidence caused by the six phytopathogens.
Antagonistic fungi, Cucurbitaceae, fungal communities, pathogenic fungi.
https://doi.org/10.22268/AJPP-001357