The effect of DIMILIN 25 WP, the common name of diflubenzuron, was first examined on the weight of ovaries and on the weight of eggs laid by females of Schistocerca gregaria. Treatment was made 24h earlier by ingestion at 30 mg/ml. DFB reduces the weight of ovaries at 8, 12 and 16 days, compared to control series of the same age. Moreover, the insecticidal treatment causes a significant reduction in the weight of eggs laid.

DFB action on ecdysteroid levels in ovaries and in eggs in females was also evaluated. The compound reduced ovarian ecdysteroid titres of the first ovarian cycle.

In laid eggs of S. gregaria females, we measured ecdysteroid content before and after enzymatic hydrolysis, to compare free and conjugated ecdysteroids in both control eggs and after DFB treatment during embryonic development. DFB significantly reduced the levels of both free and conjugated ecdysteroids compared to the control.