An enzyme immunoassay (EIA) was developed for the identification and enumeration of Pseudomonas caryophylli in soil. The EIA was conducted by incubating P. caryophylli cells with specific rabbit antibody and then determining the bound antibody with β-D-galactosidase conjugated anti-rabbit immunoglobulin. For the enumeration of P. caryophylli in soil, the yellow convex colonies on a selective medium were subjected to the EIA. As few as 10^2-10^3 CFU g^<-1> soil of P. caryophylli were identified with this method. Fluorescent antibody technique followed by image analysis was also applied for the specific detection of P. caryophylli in soil. The latter method permits the rapid determination of P. caryophylli at the lower limit of 10^4 cells g^<-1> soil.
Antagonistic Actinomycetes to F. oxysporum f. sp. licopersici and f. sp. raphani were screened for the control of Fusarium Disease. 1. Thirteen Actinomycetes which showed a high antagonistic activity to F. oxysporum were selected by 1st and 2nd screenings. No harmful effects on the germination and growth of radish was observed. 2. Five Actinomycetes selected from the 13 Actinomycetes suppressed the infection of radish yellows compared with untreated control. 3. The five Actinomycetes were identified as Streptomyces achromogenes, S. phaeopurpureus, S. hygroscopicus, S. nitrosporeus and S. baarnensis. 4. Antagonistic activity of Actinomycetes to F. oxysporum f. sp. raphani in laboratory experiments using petri dishes did not always coincide with the suppressive effect of Actinomycetes on radish yellows in soil infected with F. oxysporum f. sp. raphani. 5. These Actinomycetes showed an antagonistic activity to 7 strains of F. oxysporum. These antagonistic activities varied depending on the combination Actinomycetes and F. oxysporum used. The growth of the Actinomycetes selected by these screenings was different in media of pHs ranging from 5 to 8.
Effects of various organic materials on the microbial flora and the activities of selected antagonistic Actinomycetes to Fusarium oxysporum in soil were investigated. Thereafter, a sample of antagonistic microbial Material A (mixture of selected antagonistic Actinomycetes and organic matter, compost made of photosynthetic bacterial sludge: CPBS) was prepared and tested for its antagonistic activity to F. oxysporum and the fixation rate in soil. 1. Compost made of photosynthetic bacterial sludge (CPBS) was selected as an organic material which promotes the Actinomycetes activity in soil. 2. Antagonistic effect of Material A on radish yellows and Fusarium wilt of cucumber caused by F. oxysporum f. sp. raphani and f. sp. cucumerinum was observed. The effect was more pronounced in the case of the mixture of five antagonistic Actinomycetes than when only a single species was used. 3. The number of Actinomycetes in four different soil samples were increased by the application of Material A and they maintained a relatively constant level. However, the number of F. oxysporum was not affected by the application. 4. Activities and fixation rates of applied antagonistic Actinomycetes in soil and in/on radish roots varied with each microbial species, respectively.