Effect of phosphine dose and exposure time on postharvest quality of Hass avocado (Persea americana Mill.)

The Hass avocado in Colombia has great export potential, although its commercialization faces restrictions due to quarantine pests. Fumigation with magnesium phosphide has become a key postharvest strategy for pest control in refrigerated fruits. However, there is limited information regarding its impact on Hass avocados. This study evaluated the effect of treatments with phosphine at different concentrations (0, 200, 400, and 800 ppm) and exposure times (36 and 72 h) on postharvest quality in avocados refrigerated at 7°C. Fruit firmness, color of the exocarp and mesocarp, weight loss, and ethylene production were analyzed using a longitudinal multivariate analysis of variance. No direct damage to fruit quality was detected related to phosphine concentration or exposure time. Although significant differences in firmness and color were observed, these effects were attributed to variations in gas concentrations, such as CO2, inside the barrels, and the fruit maturation process. Ethylene production increased with higher doses and longer exposure times, reaching a significant peak 72 h after harvest, coinciding with the climacteric point. These differences were related to the physiological maturation process of the avocados. Magnesium phosphide did not directly affect the quality of Hass avocados under the evaluated conditions. Magnesium phosphide is considered a viable option for phytosanitary pest control, although further studies are needed to assess its effectiveness against specific avocado pests.