Combined chitosan and Cympobogon citratus (D.C. ex Nees) Stapf. essential oil to inhibit the fungal phytopathogen Paramyrothecium roridum and control crater rot in melon (Cucumis melo L.).

This study evaluated the efficacy of combined chitosan (Chi) and Cymbopogon citratus (DC) Stapf. essential oil (CCEO) to inhibit the fungal phytopathogen Paramyrothecium roridum L. Lombard & Crous and control crater rot in melon (Cucumis melo L.). Effects of several Chi and CCEO concentrations to inhibit the growth of four P. roridum isolates in vitro, as well as the type of interaction of some combined concentrations of Chi and CCEO was evaluated. Effects of coatings with combined concentrations of Chi and CCEO on development of crater rot lesions in melon artificially inoculated with P. roridum during storage (15 days, 25 °C) were measured. Chi (2.5, 3.75, 5, and 6.75 mg/mL) and CCEO (0.3 and 0.6 µL/mL) led to growth inhibition of the four examined P. roridum isolates. Combinations of Chi (5 mg/mL) and CCEO (0.15 and 0.3 µL/mL) had additive interaction to inhibit P. roridum. Coatings with additive combined concentrations of Chi and CCEO decreased the development and severity of carter rot lesions in melon during room storage regardless of the inoculated P. roridum isolate. Therefore, application of coatings formulated with combined concentrations of Chi and CCEO could be alternative strategies to control crater rot caused by P. roridum in melon and decrease synthetic fungicide use in this fruit.

Application of coatings formed by chitosan and Mentha essential oils to control anthracnose caused by Colletotrichum gloesporioides and C. brevisporum in papaya (Carica papaya L.) fruit.

This study investigated the efficacy of coatings formed by chitosan (Chi) and Mentha piperita L. (MPEO) or M. × villosa Huds (MVEO) essential oil to control the development of antrachnnose in papaya fruit caused by Colletotrichum gloeosporioides and C. brevisporum. Chi (2.5-10 mg/mL), MPEO and MVEO (0.15-1.25 µL/mL) alone effectively inhibited the growth of C. gloeosporioides and C. brevisporum isolates in laboratory media. Combinations of Chi (5 and 7.5 mg/mL) and MPEO or MVEO (0.15-1.25 mL/mL) inhibited the growth of Colletotrichum isolates and mostly presented additive or synergistic interactions. Development of anthracnose lesions caused by C. gloeosporioides and C. brevisporum isolates was reduced by coatings formed by Chi (5 mg/mL) and MPEO or MVEO (0.3-1.25 µL/mL) combinations during storage (10 days, 25 ±â€¯0.5 °C). Decreases in anthracnose lesion development in papaya coated with Chi (5 mg/mL) and MPEO or MVEO (0.6 and 1.25 µL/mL) were similar or higher than those caused by a comercial fungicides formulation. The application of coatings formed by combinations of selected Chi and MPEO or MVEO concentrations could be considered an alternative strategy to control papaya anthracnose caused by C. gloeosporioides and C. brevisporum.