INDUCTION OF RESISTANCE AND SEED THERMOTHERAPY FOR CONTROL OF STEWART WILT DISEASE ON CORN

Stewart wilt disease on corn caused by Pantoea stewartii subsp. stewartii was first reported its existence on corn plants in Bali, in 2017. The typical symptoms of  the disease are pale-green to yellow linear streaks parallel to the veins. The incidence of new diseases on essential commodities such as corn, it is very urgent to look for its control solutions. The pathogen contaminated seeds can be the primary source of introduction the disease to the fields. Devise strategies for disease control, it should refer to sustainable agriculture. The objective of this research is the utilization of rhizobacteria as inducers of plant resistance to stewart wilt disease, and to assess the effectiveness of various thermotheraphy treatments on reducing contamination of pathogen on corn seeds and to determine the effect of these treatments on seed germination. Two hundred isolates, which have the potential in controlling plant diseases in our laboratory’s biocontrol isolate library, were employed to this research to screen some antagonistic bacteria, which can efficiently control bacterial Stewart’s wilt disease. Based on the results of antagonistic activity experiments, two of the test isolates (CgBd and TLKC) have high abilities to control bacterial Stewart’s wilt disease. The rhizobacteria isolates were identified as Enterobacter asburiae and Enterobacter cloacae for TLKC isolate and CgBd isolate, respectively. Our recent results show that Enterobacter asburiae and Enterobacter cloacae isolates can promote the plant growth and significantly control the Stewart’s wilt disease by increasing the total phenol content and salicylic acid in plant tissues. Thermotheraphy treatment for 216 hours at 70°C was concluded to have excellent prospects. The thermotheraphy treatment regime could eliminate pathogen without an appreciable reduction in germination level of the seed and also available without any special apparatus. The study concluded that rizobakteri Enterobacter asburiae and Enterobacter cloacae  able to act as inducer agent of systemic resistance as well as plant growth promoters. Thermotheraphy treatment for 216 hours at 70°C could eliminate pathogen on corn seed.