Preherbicide Mowing and Herbicide Rate on Tropical Soda Apple (Solanum viarum) Control

Abstract

Field studies were conducted in 1993–1994 and 1994–1995 to evaluate the effects of preherbicide mowing and herbicide rate on tropical soda apple (TSA) control. Mature TSA plants were mowed one, two, or three times to a 7.5-cm stubble with a 60-d interval between mowings. Triclopyr was applied at 0, 0.6, and 1.1 kg ai/ha at 375 L/ha at 207 kPa 60 d after each mowing treatment. Mowing TSA plants twice before an application of 0.6 kg ai/ha triclopyr resulted in 100% control. Tropical soda apple control (2-yr average) for the triclopyr treatment increased between one (28% control) and two (82% control) preherbicide mowings, with no additional control benefits from three mowings (84% control). In a second study, TSA control increased from 10% 60 d after a single mowing to 92% after three consecutive mowings at 60-d intervals with no herbicide. Total nonstructural carbohydrates in TSA crowns decreased from 19.1% for unclipped plants to 4.3% 60 d after three preherbicide mowings.