Antimicrobial effect of rhizome and medicinal herb extract in controlling postharvest anthracnose of dragon fruit and their possible phytotoxicity
Paa K. Bordoh, Asgar Ali, Matthew Dickinson and Yasmeen Siddiqui
Scientia Horticulturae 265: 109249. (2020)
2020
บทคัดย่อ
A study was conducted to evaluate the antifungal effect of ginger, turmeric rhizome and “dukung anak” (medicinal herb) crude extract against Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.at minimal concentrations 2.5 g L−1, 5.0 g L−1, 7.5 g L−1 and 10.0 g L−1 (in vitro). Additionally, the possibility of using these extracts as an edible coating to control postharvest anthracnose in dragon fruits at maximum concentrations of 5.0 g L−1, 10.0 g L−1 and 15.0 g L−1 (in vivo) were elucidated. The results showed that all plant extracts possessed significant antifungal activity against C. gloeosporioides by inhibiting mycelial growth and conidial germination, and caused distortion, shrinking and swelling of fungal hyphae. Ginger crude extracts at 10.0 g L−1 showed the best effect in vitro by suppressing mycelial growth (88.48 %) and conidial germination (87.50%) which was comparable to commercial fungicide (Mancozeb) at 2.0 g L−1 (80.45%). In vivo study showed that all plant crude extract at 15.0 g L−1 compounded disease incidence (DI) and disease severity (DS) due to phytotoxicity. However, using “dukung anak” at 5.0 g L−1 or 10.0 g L−1 significantly controlled anthracnose and this was not different in turmeric-treated fruits at 10.0 g L−1 after 28 days of cold storage at 11 ± 2 °C, 80% RH. On the contrary, dragon fruits treated with ginger at 5.0 g L−1 and above experienced severe disease incidence due to phytotoxicity. In conclusion, crude extract of dukung anak or turmeric can be used as bio-fungicide to control anthracnose in dragon fruits at 10.0 g L−1, while concentration at 15.0 g L−1 and above may exacerbate diseases in dragon fruits due to phytotoxicity.