Evaluating Various Essential Oils for the Control of Anthracnose in Chives

Chives (Allium fistulosum L.) are a globally consumed culinary condiment susceptible to diseases that cause yield losses. Anthracnose, caused by Colletotrichum spaethianum, significantly affects chive production. This study evaluated essential oils (EOs) for controlling anthracnose by examining mycelial growth inhibition, conidial germination, field disease severity, and activity of β-1,3-glucanase, chitinase, and peroxidase in chive leaves. Data were analyzed using ANOVA with Scott–Knott test (5%). EOs of Lippia sidoides, L. gracilis, and Ocimum gratissimum completely inhibited mycelial growth, sporulation, and conidial germination at 0.2%. Under field conditions, L. gracilis and Piper aduncum were the most effective treatments, showing the lowest severity scores. Mentha piperita and Curcuma longa also reduced disease severity, albeit with intermediate efficacy. Additionally, EOs activated plant defense responses, particularly by inducing β-1,3-glucanase activity. The integrated approach combining in vitro, field, and biochemical analyses provides strong evidence supporting EOs as sustainable alternatives for anthracnose management. These findings are especially relevant for family farming in the Amazon, where no fungicides are registered for chives, highlighting the potential of essential oils as low-cost, viable alternatives for disease control.