INHIBITION ACTIVITY OF CLOVE HEXANE EXTRACT, CINNAMON AND DATURA ETHANOL EXTRACT AGAINST ERWINA CAROTOVORA SUB SP. ATROSEPTICA CAUSATIVE AGENT OF SOFT ROT AND BLACK STEM DISEASE

Abstract

This study was carried out to evaluate the antibacterial activity of Clove hexane extract, Cinnamon and Datura ethanol extracts against Erwinia carotovora sub sp. atroseptica causative agent of soft rot and black stem in potato on nutrient agar (NA) medium and under field natural conditions. The concentration, 0.2, 0.5, 1, 2, 3, 5% of the 3 extract were mixed with the medium (NA) before solidification, and poured in sterile Petridishes 9cm diameter. The bacterial suspension (0.1 ml from 24 brs old culture) was spread on the medium and incubated at 25:2ºC .Colonies number was determined after 48 of incubation and inhibition percentage was calculated. Results showed that clove hexane extract at 0.2% was more effective than Cinnamon and Datura ethanol extracts at the same concentration with inhibition percentages 100%, 94%, and 88.8% for the three extracts respectively. The inhibition percentage of bacterial growth at 108 CFU /ml was found to be 100% with the concentrations 0.5, 1, 3, 5% for the three extracts. The treatment of tubers or the soil with Clove, Cinnamon, and Dature extracts at 0.2, 0.5, 0.5% respectively, was led to inhibition of E.C. atroseptica growth completely (zero infection) which indicate that it is necessary to focused on the elimination of primary infection sources in control program. The application of the extracts on the foliage of plants grown from bacterial contaminated tubers was led to reduce the infection to 80% compared with 100% in control plants, which indicate that treating plants after infection is ineffective. The spraying of foliage by the extract 0.2, 0.5, 0.5% at of plants grown from uncontaminated tubers in non-treated soil, then contaminated with bacteria by the extracts of Clove, Cinnamon, Datura at 0.2, 0.5, 0.5% after 48hrs of spraying led to reduction the infection percentage to 30, ,30, and 50% respectively compared with 100% in control plants, which indicate that the active compound in the extract induced systemic resistance in the plant against the bacteria.