EFFECT OF CONVENTIONAL AND BOTANICAL INSECTICIDES ON SOIL MICROBIAL ACTIVITY

The laboratory and field studies were conducted to determine the effect of the application of conventional and botanical insecticides on microbiological activity in the soil. The trial was set up in the autumn 2007 in glasshouse of Fruit Research Institute, Cacak, Republic of Serbia. In vegetative 10-litre vessels, strawberry runners, immersed for 10 min in water heated to 46 degrees C, were planted. The trial included 4 treatment variants (I - microbiological fertiliser Enteroplantin; II - microbiological fertiliser Slavol; III - mineral fertiliser Multi KMg; IV - non-fertilised soil) as well as the application of conventional and botanical insecticides. The experiment was carried out under the randomised block design system, in 3 replications. Over the growing season, conventional measures involved the application of endosulphan (Thiosulfan 0.2%) and gusathion (Gusathion 0.15%). As for botanical insecticides, neem (NeemAzal 0.4%) and pyrethrin (Pyros 0.2%) were used as the part of organic production system. The effect of the applied insecticides was determined twice over the growing season and was monitored by checking the fungal and actinomycetes count. Indirect dilution methods of growing on adequate culture media were used to determine the number of studied microorganisms groups. The two-year results (2008-2009) suggest that the insecticides applied within conventional production system caused significant reduction in the number of the soil fungi.