Effect of the water quality (hardness, Ec and pH) on the emulsion stability of the common pesticides in pistachio orchards of Kerman province.

Chemical control plays an important role in plant protection programs. In this regards, emulsion stability of pesticides cause basic role on their effectiveness. In the present research the effects of some factore of water qualities such as EC, pH and hardness on the emulsion stability of the common pesticides which are applied in pistachio orchards were tested. Groundwater samples were taken from water wells of pistachio growing areas in Kerman province. Then, they were analyzed to determine their quality parameters as well as EC, pH, Na+, Ca2+, Mg2+, Cl-, HCO3-, SAR components and total hardness. Based on result obtained on total hardness of analyzed water samples, fifty samples were selected for following experiments like test of emulsion stability. Emulsion stability of pesticides including Endosulfan (Formulated by Shimikeshavarz Co.), Endosulfan (Formulated by Bhavarchemi Co.), Ethion (Formulated by Bhavarchemi Co. ), Ethion (Formulated by Shimikeshavarz Co), Dartone (Formulated by Giah Co.), Dartone (Formulated by Aventis Co.), Amitraz (Formulated by Shimikeshavarz Co.) and Amitraz (Formulated by Kavosh kimia Co. ) were checked in fifty water samples using method of CIPAC. The results showed that the range of EC, pH and total hardness values were 1.4 – 29.5 dS/m, 7.3 – 8.8 and 410 - 7100 mg/Lit in the fifty samples, respectively. The relationship between Electrical conductivity of water samples and emulsion instability was positive and pH of water samples did not show an important role in emulsion stability. Emulsion instability for above tested insecticides was observed in total hardness of waters containing 1850, 1350, 2200, 1750, 950, 950, 600 and 1170 mg/Lit, respectively. Emulsion of pesticides of mentioned above in total hardness of water was 2950, 4050, 4050, 4050, 2370, 2370, 5325 and 1170 mg/Lit and more than that was showed instability, respectively. Based on the results the waters with high hardness should not be used for chemical application using the above mentioned pesticides. Also the results showed that types and ratioes of the active ingredients, solvents, emulsifires and the other additives of the formulations are effective on the emulsion stability.