Oil palm (Elaeis guineensis Jacq.) is a plantation crop that is widely cultivated in Indonesia, including in Riau Province. The decline in oil palm productivity in Riau can be caused by diseases such as basal stem rot (BPB) caused by Ganoderma sp. The study aims to test the ability of chitin and its derivatives to inhibit the growth of Ganoderma sp. and to determine its effect on the morphology…