Objective:To determine the amount of azinphos methyl and diazinon residues in two river fishes, Liza aurata and Cyprinus carpio, in the north of Iran. Methods: This study was done during 2006-2007. In this survey, 152 water and fish samples from Gorgan and Qarasu rivers, north of Iran, were investigated. Sampling was done in three predetermined stations along each river. Organophosphorus compounds (OPs) were extracted from the fishes and the water of rivers. After extraction, purification and concentration processes, the amount and type of insecticides in water and fish samples were determined by high performance thin layer chromatography (HPTLC). Results:There was a significant difference in the residue of the insecticides in the water and fish samples between summer and other seasons in the two rivers. The highest amount of insecticides residue was seen during summer. In both rivers, the amount of diazinon and azinphos methyl residues in the two fishes was more than 2 000 mg/L in summer. There was no significant difference in insecticides residue between the fishes in two rivers. The diazinon residue was higher than the standard limits in both rivers during the spring and the summer, but the residual amount of azinphos methyl was higher than the standard limits only during the summer and only in Qarasu River. Conclusions:It can be concluded that the amount of OPs in the water and the two fishes, Liza aurata and Cyprinus carpio, is higher than the permitted levels.

Objective:To evaluate the efficacy of deltamethrin and find a relation between persistence and residue of this insecticide on the prevalent surfaces against malaria vectors in southeastern Iran. Methods:After indoor residual spraying on prevalent surfaces in studied areas (plaster and mud as absorbent surfaces, wood as non absorbent surface and filter paper as control) for malaria control, conical tests as a bioassay method and chromatographic method as an analytical method were used for evolution of persistence and residue of deltamethrin insecticide. Results were investigated statistically by ANOVA and Tukey-HSD tests for determining relations or differences between residue and persistence of deltamethrin. Results:According to the results, there was no significant difference between mortality rates from bioassay tests on different surfaces, and deltamethrin kept its utility to malaria vector control until 120 days after indoor residual spraying on these surfaces. In the case of residue, there was no significant relation between residue amounts and mortality rates on different surfaces, whereas this relation existed between residual amounts on filter papers and mortality rates from bioassay tests. Conclusions: This study shows that measurement of residue in filter papers is a suitable tool for evolution and dictum of efficiency of deltamethrin insecticide in indoor residual spraying for malaria control.

OBJECTIVETo evaluate the insecticidal effect of diatomaceous earth (DE) against adults and nymphs of Blattella germanica.

METHODSThis cross sectional study has been done on the laboratory strain of German cockroaches. Two stages, nymph and adult, were exposed to six dose rates of the DE, 2.5, 5, 10, 15, 20 and 25 g/m(2), at 24, 48 and 72 h exposure period. Mortality (number of dead cockroaches) was assessed after 24 h. Other exposed specimens were transferred to the beakers contained food and water for counting the retard mortality rate after 1 week.

RESULTSIncreasing in dose rates of DE increased mortality rate, so that the lowest and highest mortality rates were observed in 2.5 and 25 g/m(2), respectively. The results of the statistical analysis showed no significant difference in the lethality of 50% of DE plus water on the German cockroach nymphs.

CONCLUSIONSDue to the resistance of German cockroach against organochloride, organophosphorus, carbamate and pyrethriodes insecticides, it is suggested to use DE for insect's control.