The effect of the root powder of two timbó species (Derris urucu and D. nicou) on Musca domestica L. larvae was estimated for populations of two strains of this fly collected from two localities of São Paulo state, i.e., Jaboticabal (Jab) and Brodósqui (Bro). Analysis was performed using a logistic model, contrasting the values for the regression equations of lethal doses of the two timbó species for both fly strains. Data showed that D. urucu was more efficient than D. nicou to control the two strains, and more than twice the amount of D. nicou powder was necessary to get the same effect caused by D. urucu. There was specificity in the action of the timbó species on the fly strains. D. urucu was more efficient to control of Bro strain, while D. nicou presented more control on Jab strain.
Insecta; flies; rotenone; control
