Antagonistic and acaricidal activity of actinomycetes against pathogens and red spider mite of tea plantations

The biocontrol efficacy of some of the actinomycetes collected from different tea growing soils of south India was attempted. Ten potential actinomycetes isolates viz ., AAS2, AAS5, AAS6, AAS7, AAS15, APSA1, APSA4, APSA5 and APSA6 collected from The Anamallais and one isolate (CAS4) from The Nilgiris were screened for their antagonistic potential against tea pathogens and acaricidal activity against red spider mite under in vitro conditions. Maximum growth inhibition was recorded by CAS4 (100%) and APSA1 (82.1%) against foliar pathogens such as Pestalotiopsis theae . APSA1 cell free culture filtrate showed highest inhibitory effect (85.3%) against Glomerella cingulata followed by CAS4 (65.4%) on Cylindrocladium sp. APSA1 and CAS4 showed maximum response against stem pathogens like Hypoxylon serpens and Macrophoma sp. (80.3%), respectively. The growth of root pathogen, Xylaria sp. was completely controlled by AAS7 and APSA4. Three isolates of actinomycetes inhibited higher mortality rate of Red spider mites (RSM) where APSA1 (100%) recorded total mortality followed by AAS7 (94.0%) and APSA6 (92.0%).