Characterization and fungicide sensitivity of fungi causing postharvest deterioration in Allium sativum, Nuevo León, Mexico

Background/Objective. Garlic (Allium sativum) is a crop of economic relevance in Mexico. Nuevo León stands out in production; however, in the municipality of Aramberri, post-harvest losses have been reported due to diseases of unknown etiology. The objective of this work was to identify the fungi associated with the postharvest deterioration of A. sativum bulbs in Aramberri, Nuevo León, Mexico and to evaluate their in vitro sensitivity to fungicides. Materials and Methods. From bulbs with evidence of deterioration and necrosis, fungi were isolated in PDA medium. Four isolates were identified by morphological analysis and one isolate from each morphological species was identified by molecular analysis. The pathogenicity of the four isolates on symptom-free bulbil was evaluated. In addition, in vitro susceptibility tests of the isolates to protective and systemic fungicides were performed. Fungicides were evaluated at three concentrations and mycelial growth reduction (MGR) and conidial germination inhibition (CGI) was estimated. Results. The fungi Alternaria embellisia and Penicillium allii were identified in association with A. sativum bulbs with postharvest deterioration. P. allii showed the ability to develop internal infections from wounds; A. embellisia only showed growth on wounds. There were significant differences (p <0.0001) in the effectiveness of fungicides on the two species. Propiconazole and copper hydroxide inhibited 100% MGR and CGI in both fungi, at all doses evaluated. Conclusion. P. allii is first reported as a causative agent of green garlic rot in Mexico. This study will serve as a basis for choosing control strategies and will contribute significantly to reducing economic losses in garlic production in this region.