CHALLENGES OF CANE RIPENING USING CORSAIR (FLUAZIFOP-P-BUTYL) AND MODDUS (TRINEXAPAC-ETHYL) TO IMPROVE SUCROSE CONTENT IN SUGARCANE AT RAMU AGRI INDUSTRIES LIMITED (RAIL), PAPUA NEW GUINEA

THE USE OF chemical ripeners to improve sucrose content in sugarcane has been used in several sugar industries around the world. Chemical ripeners have not been used consistently on a commercial scale at Ramu Agri Industries Limited (RAIL) Papua New Guinea (PNG), due to a lack of in-situ research into their potential benefits and disadvantages under local conditions. Replicated field experiments were conducted at RAIL between 2014 and 2016 to evaluate the effects of Corsair (fluazifop-p-butyl) and Moddus (trinexapac-ethyl) on sucrose content and sugar production in three major varieties (Q198A, B72177 and R570) at varying spray to harvest intervals so firm recommendations for their use under commercial conditions could be made. The treatments were applied by spray aircraft. Response to ripeners was assessed based on changes in stalk sucrose content expressed as per cent of dry matter (suc%_dm), and CCS, and of course cane and sugar yields were determined at harvest. Results revealed that juice quality (suc%dm, CCS) increased significantly between 6 and 10 weeks after Corsair and Moddus treatment leading to a net sugar yield benefit of +1.0 to +1.6 and +0.4 to +1.2 ts/ha respectively. Cane yields were not affected by ripener application, but there were varietal effects associated with adaptation to the varying growing and environmental condition. Ripeners did not cause any increase/decrease in cane quality and sugar yield when harvesting period was delayed beyond 11 weeks after spray. Therefore future trials will be focused on determining optimum spray to harvest intervals. Unplanned cane fire is a main constraint here at present, and frequent changes to harvest programs would mean that ripeners that has the delayed ripening effect on cane quality would be the best option. On this note, Moddus was the first choice for commercial application in 2017 due to its longer lasting effect than Corsair. This report contains data from two identical replicated trials and the summary results are discussed in the text.