Colletotrichum Gloeosporiodes is one of the pathogenic fungi that causes fruit rot disease in apple plants. The control that has been widely used so far is chemical fungicides which cause negative effects, it is necessary to use an alternative control using antagonistic fungi that is safe and environmentally friendly. This study aims to determine the inhibition of several antagonistic fungi against the growth of the pathogen C. gloeosporiodes. The method used was a completely randomized design (CRD) with 4 types of antagonist fungi, 1 control and 5 replications. Antagonism test using dual culture method between antagonistic fungi Trichoderma harzianum, Trichoderma viridae, Trichoderma koningii, and Gliocladium sp. with C. gloeosporiodes. The test results showed that the antagonist fungus that had the highest percentage of inhibition against C. gloeosporiodes was T. harzianum at 87.8% and had a high inhibitory power category with a crude extract chitinase enzyme activity value of 4.30 U/mL and Gliocladium sp. has the lowest percentage of inhibition 64.3%. Based on these results, it can be concluded that T. harzianum has a high potential to control fruit rot disease in apples because it contains the chitinase enzyme which can degrade the cell wall of the pathogenic C. gloeosporiodes.

No abstract

Apple fruit rot disease is one of the major apple diseases in Indonesia. It has been caused by several species of pathogenic within the genus Colletotrichum. This research aims to identify species of the pathogen causing apple fruit rot disease in Pujon, East Java. Suspected fungal isolates were identified based on morphological (macroscopic and microscopic) and molecular characteristics. Based on the morphological observation, five isolates were identified as Colletotrichum spp. These isolates have similar morphological characteristics such as white-greyish colony color, texture colony velvety, zonation conidia concentric, round cylindrical conidial end, and conidia with 10.4–12.8 ?m in length and width 3.1–3.52 ?m, respectively. Isolates M1 showed the highest pathogenicity, therefore selected for molecular identification. Molecular identification was conducted using ITS1 and ITS4 primer, AM1 was identified as C. gloeosporioides with 99.57% similarity to C. gloeosporioides JX-19 variety from China.