Pseudomonas fluorescens and other nonpathogenic pseudomonads
may be better suited for damping-off and root rot control as
compared with endospore-forming Bacillus, which need to germinate,
produce vegetative cells, colonize the spermosphere and
rhizosphere, and synthesize their antifungal compounds in time
to prevent infection (Georgakopoulos et al. 2002). We did not
measure in our study any difference in biocontrol efficacy between
P. fluorescens and B. subtilis. Although bacterial survival in a
carrier material may be a challenge for their development into
commercial products, pseudomonads have been described as successful
biocontrol bacteria (Capper and Higgins 1993; Duffy and
Weller 1995; McCullagh et al. 1996; Williams and Asher 1996;
Bagnasco et al. 1998) and excellent root colonizers (Van Loon et al.
1998). Fluorescent pseudomonads also show compatibility with
fungicides (Salman and Abuamsha 2012), suggesting their use in
integrated disease management. However, both Pseudomonas and
Bacillus show key properties of an effective biocontrol agent, i.e.,the rhizosphere competence, plant growth promotion, and antipathogenic
activity (Nautlyal et al. 2002).