Biocontrol of Fusarium wilt disease in strawberries using bioorganic fertilizer fortified with Bacillus licheniformis X-1 and Bacillus methylotrophicus Z-1.

Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae is one of the most serious indigenous soil-borne fungal disease of strawberry. In this study, we have identified and investigated two sets of bacterial samples: Bacillus licheniformis (X-1) and Bacillus methylotrophicus (Z-1). Both of them were isolated from the rhizosphere soil of healthy strawberries which showed a strong inhibitory effect on Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae. Bioorganic fertilizer developed by our team exhibiting a strong inhibition ability against the pathogen in comparison with the chemical and organic fertilizers. It allowed 80% disease free strawberry production together with improved physical and biochemical indexes in the pot experiments. The enzyme activity analysis of SOD, PPO, POD, and CAT in the bioorganic fertilizer (BOF) group showed significant increase with values; 48.8%, 68.7%, 85.9%, and 41.1% than that of the control group, respectively. The results of bacterial diversity showed that Bacillus in group BOF was almost three times as large as in the healthy soil control group (CK). Besides, the results of microbial diversity showed that Fusarium and Fusicolla of BOF was nearly five times less than that in CK and chemical fertilizer groups, where the Bacillus content reached to three times as much of the CK. Moreover, the enzymes activity and the content of beneficial microorganisms in the rhizosphere increased significantly. In this study, the bioorganic fertilizer developed by the isolated strains had significant effects on the control of strawberry Fusarium wilt disease. Our results demonstrate that BOF is a promising approach to control this disease in strawberry production. © King Abdulaziz City for Science and Technology 2020.