Effectiveness of Bio-agent Formulations on Suppression of Lupine wilt Caused by Fusarium oxysporum f. sp. lupini

Abstract

This study aimed to evaluate the bio-agent formulations of Trichoderma harzianum, Bacillus subtilis and Pseudomonas aeruginosa for the protection of lupine plants against wilt disease caused by Fusarium oxysporum f. sp. lupini . T. harzianum isolate (T1), P. aeruginosa isolate (P1) and B. subtilis isolate (B3) were the most effective ones in reducing the growth of F. oxysporum f. sp . lupini in vitro . Consequently, these isolates were used as bio-agent to control wilt on lupine plants in greenhouse experiments. The bio-agent isolates administered in the form of cells in broth media, powdered cells, and immobilized cells on sawdust as formulations were tested for their abilities to control lupine wilt in a greenhouse compared to Captan fungicide. Soil treatments with the three bio-agent formulations (broth medium or cells powder and sawdust) showed a markedly great reduction in wilt disease severity. Although all the formulations reduced the wilt disease severity compared to the water treatment, using the cells powder formulation of bio-agent reduced the wilt severity more than broth medium and sawdust formulations. In all formulations, T . harzianum (T1) exhibited the highest effect in the control of wilt compared with other bio-agent treatments. The sawdust and powder bio-agent formulations significantly reduced the disease severity of wilt on Lupine, as well as improved growth parameters (shoot, root, and plant length and seed yield/plant) of lupine plants compared with control treatment.