Toxicity Of Benzoylphenylureas To The African Armyworm Spodoptera-Exempta (Walker)

Four benzoylphenylureas, assessed under laboratory conditions, have a high level of activity against third-instar larvae of Spodoptera exempta (Lepidoptera: Noctuidae). The LC50 values were 0.013, 0.035, 0.074 and 0.138 mug ml-1 48 h after exposure; 0.006, 0.007, 0.035 and 0.062 mug ml-1 72 h after exposure and 0.001, 0.004, 0.013 and 0.010 mug ml-1% h after exposure for teflubenzuron, hexaflumuron, flufenoxuron and diflubenzuron, respectively. In relation to ovicidal activity, the LC50 values were 0.186, 0.490, 0.947 and 5.834 mug ml-1 to eggs 0-24 h old and 0.420, 1.085, 5.966 and 18.493 mug ml-1 to eggs 24-48 h old, for hexaflumuron, flufenoxuron, teflubenzuron and diflubenzuron, respectively. The LC95 value for hexaflumuron was <4 mug ml-1 to the eggs. Teflubenzuron, hexaflumuron, flufenoxuron and diflubenzuron are extremely effective pesticides and can be tested against larvae of S. exempta in the field. Hexaflumuron, flufenoxuron and teflubenzuron can also be tested for their ovicidal activity.