Efficacy of Methyl Jasmonate and Calliette in the Management of Black Spot Disease of Pineapple (Ananas comosus) Caused by Fusarium moniliforme var. Subglutinans

Pineapples play an important role in the lives of people. However, they are threatened by black spot disease caused by Fusarium moniliforme var. subglutinans, which destroys 30% of production. Unfortunately, chemical methods of controlling this disease have proven ineffective due to resistance, environmental pollution, health, and even biodiversity. To find more effective alternatives for sustainable agriculture, 50 mL of a solution containing calliette (5 mM) and methyl jasmonate (10 mM) was sprayed on pineapple plants 72 h before being inoculated with 2.5 mL of the fungal strain (104 spores/mL). The overall objective was to stimulate polyphenol production in pineapple to effectively induce natural resistance against Fusarium moniliforme var. subglutinans. Disease incidence was estimated after flower inoculation and fruit opening at harvest. Ten (10) plants per treatment were used with three (3) replicates. Polyphenols isolated from leaves were identified by HPLC. The direct effect of polyphenols on mycelial growth was evaluated. The results showed that the biocontrols mobilised 654.22 mg/g of defence polyphenols to resist the disease, representing a 4.5-fold increase compared to the control. The severity of the illness has decreased to 0° (no symptoms). The chromatographic profile revealed the presence of thirteen polyphenols, including seven pre-existing amplified polyphenols and six newly synthesised ones. The use of biocontrol agents is therefore an effective way to protect pineapples against black spot disease. Looking ahead, it would be interesting to expand this study by using other biocontrols, particularly polysaccharides extracted from the pathogen. This approach opens the door to the principle of vaccination.