Mycobiota of apple fruit: effects on bitter rot caused by Colletotrichum acutatum
O.S. Dharmaputra, A.S.R. Putri, A.U. Dewi
Acta Horticulturae 975: 223-229. 2013..
2013
บทคัดย่อ
Colletotrichum acutatum is a pathogenic fungus causing bitter rot on fruit, including apple. Biological control of post-harvest diseases of fruit has emerged as a promising alternative to chemical applications. The objective of this study was to test the antagonistic potential of mycobiota of apple fruit (‘Malang’ and ‘Manalagi’) against C. acutatum. Fruit were collected from several traditional markets and supermarkets in Bogor and Jakarta, and from an orchard in Batu (‘Malang’). Test fungi were isolated using a dilution method, followed by a pour-plated method on malt extract agar (MEA) containing chloramphenicol. The test of antagonism was conducted using the direct opposition method on MEA; the pathogenicity of test fungi was done by inoculating fungal isolates onto the two apple cultivars. The potential antagonistic fungus was evaluated by inoculating a 0.1 ml conidial suspension with different concentrations (1×106; 2×106; 4×106; 6×106; 8×106; 1×107 conidia/ml) onto the apples. Forty-nine isolates of test fungi were isolated from the apples. Eight out of 49 test fungal isolates inhibited growth of C. acutatum by more than 50%, and 6 out of 8 fungal isolates prevented disease developing on the inoculated apples. One of the antagonistic fungus, i.e., Pestalotiopsis guepinii with different concentrations of conidial suspensions were not able to control bitter rot effectively. Nevertheless, P. guepinii (4×106 conidia/ml) inoculated together with a 0.1-ml conidial suspension of C. acutatum (1×106 conidia/ml) inhibited bitter rot by 39.5%.