The ovicidal and larvicidal effect of dimilin on Tabanus triceps and Chrysops dispar (Diptera: Tabanidae)

Abstract

The insecticide diflubenzuron, Dimilin, was applied topically to the eggs of Tabanus triceps and Chrysops dispar. Mean per cent hatchability of these eggs at various concentrations ranging from 1 to 150 ppm were observed. The hatchability depended upon the age of the egg and increased with age. A minimal dose of 10 ppm of diflubenzuron caused 100% mortality (no hatchability) at the age of 48 hr in both species. The per cent hatchability was inversely proportional to the concentration of Dimilin. The larvicidal effect of Dimilin was also noted. Larval mortality (100%) was observed after 60 hr treatment. The larval mortality was directly proportional to the concentration of Dimilin. The results show that Dimilin has potential for controlling Tabanid vectors.Resume-L'insecticide diflubenzuron, le Dimilin a ete depose sur des oeufs de Tabanus triceps et Chrysops dispar. Le taux moyen du pourcentage d 'eclosion de ces oeufs a des concentrations variees, allant de 1 a 150 ppm a ete observe. La capacite a l'eclosion depend de l'age des oeufs et elle augmente a mesure que I'oeuf avance en age. line dose minimale de 10 ppm de diflubenzuron cause 100% de mortalite chez des oeufs ages de 48 heures dans les 2 especes. Le pourcentage d'eclosion est inversement proportionnel a la concentration de Dimilin. L'effet larvicide est egalement note et une mortalite larvaire de 100% est observee apres 60 heures de traitement. La mortalite larvaire est directement proportionnelle a la concentration de Dimilin. Les resultats montrent que le Dimilin est un insecticide potentiel, qui peut etre utilise pour contrdler les Tabanides vecteurs. Mots Cles: Dimilin, eclosion des oeufs, Tabanus triceps, Chrysops dispar, mortalite larvaire 8 8 © c«-i S 8 oo © ON © 8 8 ; od in X X z z IN d ON O\ © m © q t o i