RESPONSE OF TROPICAL SODA APPLE (SOLANUM-VIARUM) TO TRICLOPYR

Tropical soda apple (Solanum viarum Dunal) is a serious broadleaf weed which has spread to 200 000 ha in Florida since 1990. A study was con ducted during 1993-94 and 1994-95 to determine the effect of mowing an d triclopyr, [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid, applicatio n on tropical soda apple (TSA) control in south-central Florida. The e xperimental design was a split plot with mowing (mowed vs non-mowed) a s whole plots and a 2 x 2 factorial arrangement of triclopyr rates (0. 56 and 1.12 kg ha(-1) a.i. triclopyr); and with herbicide applications [single, at 0.56 and 1.12 kg ha(-1); and sequential, at 0.56 + 0.56 ( 30 d later) or 1.12 + 1.12 kg ha(-1) (30 d later)] plus a control, as subplots. Whole plots were arranged in four randomized complete blocks . Response variables consisting of seedling emergence and TSA adult pl ant control were recorded monthly. Highest seedling emergence occurred between August and March, with little emergence between April and Jul y. Mowing adult TSA plants 60 d prior to herbicide application general ly provided better (P < 0.05) control than herbicide-treated, non-mowe d plants. Sequential application of triclopyr 0.56 + 0.56 kg ha(-1) (3 0 d later) provided excellent, consistent (P < 0.05) control compared with 1.12 kg ha(-1) in a single application, with no effect on bahiagr ass (Paspalum notatum Fluegge). These data demonstrate herbicide/cultu ral practice treatments that can successfully control TSA in bahiagras s pastures.