Abstract
Growth and ripening effects of Polaris [N,N-bis (phosphonomethyl) glycine] and CP 70139 were examined in early-adult sugarcane. Both materials, products of the Monsanto Company, were tested at concentrations of 100, 300, 900 and 2700 p/m, applied until runoff as aqueous foliar sprays. Similar responses were obtained relative to foliar injury symptoms, growth repression, juice quality improvement, acid invertase inhibition, and tissue sugar and protein changes. Optimal Polaris responses were at 2700 p/m. CP 70139 produced comparable effects at 300 or 100 p/m. The magnitude of invertase repression and juice quality improvement was identical for the two compounds, suggesting that CP 70139 is more efficient rather than more active than Polaris. It is suggested that, at concentrations equal to Polaris. CP 70139 should produce a greater degree of ripening under field conditions where chemical penetration of the closed-in canopy is limited. Both materials gave evidence that growth repression and ripening occur as independent processes.