EVALUATION OF THE EFFECTS ON SOIL CARBON MINERALIZATION OF DELTAMETHRIN AND LAMBDACYHALOTHRIN USED TO CONTROL OF SOME INSECTS IN OLIVE ORCHARDS

Abstract

Deltamethrin and lambda-cyhalotrin are insecticides widely used in Turkish olive trees (Olea europaea L., Oleaceae). An experiment was conducted to determine effects of deltamethrin and lambda-cyhalotrin on soil microorganisms and their microbial activities by carbon mineralization. Both insecticides (25 g of active ingredient 1(-1) for deltamethrin and 50 g of active ingredient 1(-1) for lambda-cyhalotrin) were applied to the soils of olive trees growing on Adana (Karatas) and Osmaniye (Faktusagi) under Mediterranean climate conditions at different doses (the recommended dose: RD, 2 and 4 folds of RD) and then incubated under the same laboratory conditions (28 degrees C at 80% of field capacity). for 45 days by the CO2 respiration method. Cumulative C(CO2) respired of Adana control soil was significantly lower than both 4xRD of deltamethrin and RD of lambda-cyhalotrin in same soil (P = 0.000 ve P = 0.002, respectively). C mineralization ratio of soil added 4xRD of deltamethrin in Adana was significantly higher from all the other treatments (P < 0.05). Deltamethrin was more biodegradable insecticide than lambda-cyhalothrin for soil microorganisms in Adana olive soil. It might be explained that deltamethrin has shorter half life and different chemical content than lambda-cyhalothrin. In our study, the impact of insecticides on carbon mineralization was dependent upon type of insecticide, insecticide dose and incubation time.