Effectivity of the Consortium of Rhizobacteria and Endophytic Bacteria to Controls the White Tip Disease of Rice Caused by Seed-Borne Nematode Aphelenchoides besseyi

Abstract

Aphelenchoides besseyi is a seed-borne nematode that causes white-tip disease in rice. Yield losses due to this nematode infection reach 30-50% in various countries. This research aimed to investigate the effectiveness of a consortium of rhizobacteria and endophytic bacteria in controlling the white tip disease while promoting the growth of rice seeds infected by A. besseyi. The experiments conducted were a bacterial compatibility test, in vitro test to examine the nematicidal activity of bacterial consortium, and an in vivo test to investigate the effectiveness of bacterial consortium to suppress disease occurrence and promote the growth of rice. The research was conducted at the Plant Protection Laboratory, Faculty of Agriculture, University of Jember from July 2020 to December 2020. The experiments used a randomized block design with five concentration levels of bacterial suspension of 20%, 40%, 60%, 80%, and 100%. The results showed that the endophytic bacterial consortium effectively controlled the growth of A. besseyi up to 80% compared to control. Furthermore, the percentage of white tip symptoms in the control plant reached 83%. In comparison, it was observed lower in a range from 74.5% to 25% in plants treated with a suspension of endophytic bacterial consortium. The control plant’s symptom length reached 3.94 cm, while the average symptom length in the treated plant ranged from 3.41 cm to 1.50 cm. The application of endophytic bacteria was also found to accelerate plant growth by increasing plant height and root length of the rice plant. The effectiveness of a consortium of rhizobacteria and endophytic bacteria to control white tip disease while increasing plant growth of rice in Indonesia is first reported in this manuscript.