Critical impact of defoliation on garlic yield during key developmental stages

Abstract

The objective of this work was to evaluate the effect of defoliation levels at different growth stages of garlic plants on total and marketable yields. The experiments were conducted during two crop seasons, when five dates (30, 60, 90, 110, and 130 days after planting – DAP) and four levels (33, 50, 67, and 100%) of defoliation were evaluated. The critical period for leaf loss in garlic crop occurs between 90 and 110 DAP (phenological stages 400 to 407), corresponding to the onset of bulbification and maximum leaf area index. Increasing defoliation levels progressively reduces marketable garlic yield, reaching losses of up to 50% under 50% defoliation and up to 100% under total defoliation during the critical period. Defoliation reduces the proportion of high-grade bulbs (grades 5, 6, and 7) and increases non-marketable production, severely impacting crop profitability.