Phytotoxicity and insectoacaricidal activity of actinomycetes isolated from saline soils of arid territory

Abstract

Aim. The purpose of these studies is to assess the phytotoxicity and insectoacaricidal activity of actinomycetes culture fluid. The results of phytosanitary monitoring on plantings of crops indicate the massive development of pathogens of viral phytopathogens which can spread through insects – pests and ticks. In this connection, the study of soil actinomycetes of the Astrakhan region provides a promising direction for creating a microbial preparation for regulating pests which are carriers of phytopathogenic viruses.Material and Methods. The phytotoxicity of the actinomycetes culture fluid was assessed in laboratory experiments on seeds of the Novichok tomato variety. Acidic and acaricidal activity was determined in the laboratory by a method based on contact interaction between the preparation and the test object.Results. As the result of the studies, ten isolates showed a phytotoxic effect on the Novichok tomato. The highest biometric indicators of the plants studied – biomass (15.3‐17.0 mg), root length (3.7‐5.0 cm) and stem length (2.0‐2.7 cm) were found in variants with isolates No2, No3, No 10, No11 and No18, which also had high rates of seed germination. These isolates most actively suppressed the vitality (90‐100%) of melon (Aphis gossypii Glover.) аnd legume (beet) (Aphis fabae Black.) аphids and spider mites (Tetranychus urticae Koch.) in laboratory conditions.Conclusion. The study of isolates No2, No3, No10, No11 and No18 showed high insectoacaricidal activity and phytostimulating properties. Using 16S DNA sequencing, 2 strains, No2 and No18, that are represented by Nocardiopsis umidischolae species, were identified.

Keywords

• actinomycetes
• streptomycetes
• phytotoxicity
• insectoacaricidal activity
• saline soils