The biological control agents of endophytic actinomycetes was investigated
to determine whether control of bacterial speck of tomato, caused by Pseudomonas
syringae pv. tomato (Pst). From natural infected tomato leaves showing bacterial
speck disease symptoms, six isolates of Pst (Pst1, Pst2, Pst 3, Pst4, Pst5,
and Pst DC3000) were isolated, it proved to be pathogenic and able to infect tomato
plants under greenhouse condition, causing speck disease symptoms. From
the eighty eight isolates of endophytic actinomycetes recovered from healthy tomato
leaves plants, nine isolates were selected and tested for their potential inhibition
against bacterial tomato speck disease in vitro and in vivo. According
to16SrDNA analysis the isolates TR-24 and TR-26 of isolated actinomyces
proved to be Streptomyces glaucescens. While the isolates TR-20, TR-32 and
TR-34 were identified as Streptomyces graminisoli and isolates TR-25 identified
as Streptomyces flavovirens as well as isolates TR-33 and TR-35 were identified
as Streptomyces scabies. Finally isolate TR-36 was identified as Streptomyces
roseochromogenus. Application of nine isolates of Streptomyces by spraying or
drenching methods, all Streptomyces isolates were able to reduce disease severity
of bacterial speck compared to infected control. Minutely, the spore suspensions
of TR-24 and TR-26 isolates gave the highest reduction of the disease severity.
However, the lowest reduction was achieved by isolate TR-35 compared with
other Streptomyces isolates.