ABSTRACT
Treatments with microbial antagonists to control plant pathogens are normally carried out as prophylactic and protective measures, as curative effects of antagonists could not be expected (Chalutz and Wilson, 1990; Andrews, 1992). However, results from Korsten et al. (1995) indicate that treatments carried out after arrival of the pathogen could contribute to plant protection. Singh and Deverall (1984) observed some effectiveness of the culture filtrate of B. subtilis when applied 24 hours after inoculation with the pathogen. In most cases treatments after inoculation were less effective or ineffective as compared to those carried out prior to inoculation, which gave effective control (Chalutz and Wilson, 1990; Korsten et al., 1997). According to these observations, timing of treatments has a central role regarding the performance of antagonists. Meeting the optimal point of time is of utmost importance with decreasing capability of antagonists to survive in the new habitat and with increasing importance of a high population density of the antagonist for sufficient efficacy.
