Dispersion of Standard and Cellulose-Augmented Termiticides in ‘ABC’ Gravel Foundation Fill

Six different commercial liquid pyrethroid termiticide formulations commonly used in building construction termite control applications to fill materials were individually applied at label rates to the horizontal surface and within perimeter and utility pipe trenches of ‘aggregate base course’ (ABC) gravel fill commonly used for building foundation construction in Arizona. Three termiticides contained finely powdered cellulose additive and three did not. Cellulose-augmented termiticides were retained in significantly greater concentrations in uppermost ABC partitions compared with their counterpart non-cellulose termiticides that contain the same active ingredient. Residues decreased with increasing depth. Cellulose-augmented permethrin applied to the surface of loamy soil from Mississippi and sandy soil from Florida also resulted in decreasing active ingredient concentrations with depth. Additionally, ABC perimeter trenches and trenches around upright utility pipes penetrating through the fill received by-the-label termiticide applications, resulting in relatively greater variability of vertical dispersion compared with vertical filtering effects associated with surface applications.