Evaluation of fungicides and Trichoderma spp. for controlling soil-borne fungal pathogens in melon crops

Avaliação de fungicidas e Trichoderma spp. no controle de fungos patogênicos habitantes do solo em meloeiro

ABSTRACT

Soil-borne fungal pathogens pose an increasing challenge to melon cultivation globally. The demand for reduced agrochemical use in melon farming, driven by limitations on chemical residues in the fruit, underscores the need for alternative control strategies. This study assesses the effectiveness of various fungicides-difenoconazole, fluazinam, fludioxonil, and procymidone -and Trichoderma spp. strains (T. asperellum, T. harzianum, and two strains of T. longibrachiatum) in combatting Ceratobasidium sp., Fusarium falciforme, Macrophomina phaseolina, and Monosporascus cannonballus. Fluazinam (EC₅₀ from 0.01 to 0.88 mg/L) and fludioxonil (EC₅₀ from 0.01 to 0.07 mg/L) emerged as the most effective fungicides in suppressing the mycelial growth of the pathogens in vitro, whereas procymidone (EC₅₀ from 2.31 to 9.77 mg/L) was the least effective. Fludioxonil demonstrated significant efficacy against Ceratobasidium sp., F. falciforme, M. phaseolina, and M. cannonballus. In vitro assays revealed that all tested Trichoderma spp. strains significantly inhibited mycelial growth, with over 70% reduction for all pathogens examined. Field trials indicated that Trichoderma treatments could decrease disease incidence (28.00 to 69.33%) and severity (0.95 to 2.25) in melon crops. These findings illuminate the potential of various fungicides and Trichoderma spp. in managing soil-borne pathogens in melon cultivation. Such control methods might be employed independently or synergistically with other strategies like grafting onto resistant rootstocks or breeding for resistance to mitigate the threats these pathogens pose to global melon production.

Keywords: Cucurbits; Biological control; Soil-born fungi; Hypocreaceae