title: The insecticidal effect of diatomaceous earth against adults and nymphs of Blattella germanica.
abstract: OBJECTIVE
  To evaluate the insecticidal effect of diatomaceous earth (DE) against adults and nymphs of Blattella germanica.
  
  
  METHODS
  This 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.
  
  
  RESULTS
  Increasing 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.
  
  
  CONCLUSIONS
  Due to the resistance of German cockroach against organochloride, organophosphorus, carbamate and pyrethriodes insecticides, it is suggested to use DE for insect's control.
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyyed Akbar
authors.initials: SA
authors.lastname: Hosseini
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sahar
authors.initials: S
authors.lastname: Bazrafkan
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Vatandoost
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Abaei
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Bandar Abbas University of Medical Sciences, Bandar Abbas, Iran.
authors.forename: Mussa Soleimani
authors.initials: MS
authors.lastname: Ahmadi
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Tavassoli
authors.affiliation: Medical Entomology and Vector Control Department, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mansoreh
authors.initials: M
authors.lastname: Shayeghi
keywords: Adult; Diatomaceous earth; German cockroach; Insecticidal effect; Insecticides; Nymph