DIFFERENTIAL LARGE CRABGRASS CONTROL WITH HERBICIDES IN TALL FESCUE AND COMMON BERMUDAGRASS

Pendimethalin and oxadiazon are used commonly to control crabgrasses (Digitaria spp.) in tall fescue (Festuca arundinacea Schreb.) and common bermudagrass [Cynodon dactylon (L.) Pers.]. A field experiment was conducted for 2 years to determine if reduced pendimethalin and oxadiazon application rates would control large crabgrass [D. sanguinalis (L.) Sco.] effectively in tall fescue and common bermudagrass. Oxadiazon applied at 1.1 kg a.i./ha in each of two applications at a 60-day interval (less than recommended rate) effectively controlled large crabgrass (greater-than-or-equal-to 3%), regardless of turfgrass species. Pendimethalin applied at 1.1 kg a.i./ha in each of two applications controlled large crabgrass in common bermudagrass effectively (greater-than-or-equal-to 90%) but not large crabgrass in tall fescue (47%). The difference in pendimethalin performance between the two species was attributed to the ability of common bermudagrass to compete more successfully than tall fescue with large crabgrass during late summer.