Antifungial activity of milkweed (Euphorbia hirta L.) in the control of moniliasis (Moniliophthora roreri Cif.) of cocoa (Theobroma cacao L.)

Abstract

The cocoa crop (Theobroma cacao) is constantly affected by diseases that can considerably compromise its production, among them moniliasis (Moniliophthora roreri). The search for alternative control measures to reduce its presence in the field is imperative; therefore, the objective of this study is to evaluate the effect of Euphorbia hirta extract on M. roreri, a cocoa pathogen. The study consisted of two phases: in vitro and in vivo in the field. The in vitro experiment was established under a completely randomized design with treatments using different concentrations of the extract (1, 2, 3, 4, 5, 6, 6, 7, 8, and 9%) to modify the culture medium and control (T0). Spore germination and mycelial growth of M. roreri were evaluated. The results revealed that milky extract (E. hirta) at a concentration of 9% v/v inhibited 100% of spore germination and 79.78% of mycelial growth. In the field trial, a completely randomized block design was used where three treatments were applied to the fruit (less than three months old) and a control: E. hirta extract with concentrations of 10% (T1) and 5% (T2), a chemical control based on copper oxide (T3) and the control (T0).