DIAGNOSIS DAN PENGENDALIAN PENYAKIT ANTRAKNOSA PADA PAKIS DENGAN FUNGISIDA

Abstract

Leatherleaf fern is an important export commodity of floriculture.  One of the most destructive disease on leatherleaf fern is anthracnose. The aim of this study was to identify the causal agent of antracnose-like disease on leatherleaf fern, to detect the pathogen in soil, and to control the disease with fungicides. Diagnosis was done with modified Koch Postulate. Identification of the pathogen was done by direct observation from the symptom under microscope. Isolation of the pathogen from die back leaves and soil was done on PDA. Inoculation was done on apple fruit indicator. The tested fungicides were difeconazole, benomyl, mancozeb+cymoxanil 8/64, tebuconazole, acebenzolar e-methyl+mancozeb 1/48, mancozeb, and 73.8% mancozeb + 6.2% carbendazim. In vitro test was done by poisoned food technique at 0% (checked), 0.025%, 0.05%, 0.1%, 0.2% and 0.4% concentration, while field test was done at 0.4% level concentration. Field application of pesticides was conducted by spraying twice a week for eight weeks. The result showed that the anthracnose-like disease of leatherleaf fern was anthracnose caused by Colletotrichum sp. The pathogen was found and survived in soil. In vitro test showed that 0.4% was the best concentration to inhibit mycelium growth. Based on this result, field experiment  was done on 0.4% concentration of fungicides. The mixture of 73.8% mancozeb and 6.2% carbendazim  was the most effective fungicide to inhibit Colletotrichum sp. in vitro. Spraying with 0.4% concentration eight times significantly reduced disease intensity in the field.