Synergistic Inhibition — Strobel and Porter 



125 



B 



Figure 2. Synergistic inhibition of Festalotia sp. (PESP) in a liquid glucose-salts medium amended with sodium 

 salicylate (SA) and/or fluids from the 18 day potato-dextrose broth culture of an unidentified mixed brown bacterial 

 culture (BRCF). Columns 1, 3, and 5 contained no SA, whereas columns 2, 4, and 6 were amended with 2.0 niM SA 

 (final concentration). Rows A, B, C, and D were amended with 0, 50, 100, 200 jxl of BRCF, respectively. Plating of 

 BRCF aliquots onto potato-dextrose agar revealed the absence of live bacteria (no growth). 



a strong synergism was observed in combina- 

 tions of 4.0 mM SA with the higher NMRTU 

 concentrations employed (1/20X, 1/10 X, and 

 1/5 X dilutions). Microscopic investigations re- 

 vealed that diverse bacteria were detectable in 



both NMC and NMRTU products (when plat- 

 ed onto PDA), but only those in NMRTU ap- 

 peared to multiply after addition to GS. Be- 

 cause a review of several preliminaiy experi- 

 ments revealed that inhibition of fungi by 



Table 7. Synergistic inhibition of Botnjtis cinerea mycelial growth by sodium salicylate (SA) and a ready-to-use com- 

 mercial formulation of neem oil extract (NMRTU). NMRTU dflutions were achieved by adding 0-100 |xl NMRTU to 

 wells containing sufficient liquid glucose-salts medium to yield 0.5 ml total volumes. Final SA concentrations of 4.0 

 mM were achieved by adding 20 (xl of a 100 mM SA stock per well. The extent of mycelial growth (mm) from inoculum 

 plugs was measured after a 48 hour incubation period. Data are mean ± standard error of six replicate wells (n = 6), 

 for each SA 0.0 mM-NMRTU combination, and three replicate wells (n = 3) for each SA 4.0 mM-NMRTU combi- 

 nation. Other abbreviations: OPC, observed percent of control. 





NMRTU 0 



NMRTU I/IOOX 



NMRTU 1/50 X 



NMRTU 1/20 X 



NMRTU 1/10 X 



NMRTU 1/5X 



SA 0.0 mM 



4.3 ± 0.1 



4.2 ± 0.1 



3.8 ± 0.1 



3.7 ± 0.1 



3.7 ± 0.1 



3.0 ± 0.2 



OPC 



100 



98 



88 



86 



86 



70 



SA 4.0 mM 



3.7 ± 0.2 



3.3 ± 0.2 



2.7 ± 0.2 



0.7 ± 0.4 



0.0 ± 0.0 



0.0 ± 0.0 



OPC 



(86) 



77 



63 



16 



0 



0 







SYN 



SYN 



SYN 



SYN 



SYN 



