Activity of boric acid on German cockroaches: Analysis of residues and effects on reproduction

In order to complete previous studies, boric acid (an inorganic compound) was evaluated on reproduction during the first gonadotrophic cycle (0, 2, 4 and 6 days) of the German cockroach, Blattella germanica (Insecta, Dictyoptera). The compound was incorporated into the diet and orally administrated at two concentrations 8.2 and 49.6% corresponding to LC50 and LC90, respectively. The observed effects were correlated with the amount of boric acid detected into the body. Data showed that boric acid reduced the number of oocytes per paired ovaries and the size of basal oocytes. Furthermore, the compound was examined on ovarian contents of proteins, lipids and carbohydrates. Results from biochemical analyses revealed a significant reduction of ovarian constituents with the two tested doses. Finally, the quantity of boric acid really incorporated into the body was determined for the two tested doses (LC50 and LC90) during the first six days of the adult life. The amounts of residues incorporated into the body increased as a function the doses and the period of treatment.