The Potential of Bacillus subtilis subsp. subtilis RJ09 as a Biological Control Agent Against Leaf Spot Diseases on Clove

Cloves is one of the main plantation commodities and native to Indonesia. Leaf spot disease with necrosis symptom often found in clove plants. Interferences photosynthesis caused by leaf can cause plant death. Bacillus known inhibit development pathogens through nutrient competition antibiosis mechanism. This study aims identify sp. RJ09 molecular approach determine its potential suppressing Pestalotiopsis sp., vitro examination. Identification fungus was carried out observing morphology which included color colony, shape size conidium isolated fungus. performed polymerase chain reaction (PCR) using a pair primers that amplified gyrB gene region ±1400 bp, followed sequence analysis. The ability as biological agent against fungi associated determined an double culture method. black necrotic spots on leaves. Molecular identification showed highest similarity value 99.40% B. subtilis subsp. subtitles. In dual growth colonies 75%.