Preliminary Investigations of an Oil Based Ethephon Mixture (Motex Plus) on Low Intensity Harvesting Systems of Rubber

Abstract

Low intensity harvesting (LIH) systems facilitate to reduce the cost of production (COP)through the reduction in the cost of tapping and also to minimise the harvester requirement inrubber plantations. In addition, considerable financial benefits are expected due to theincrease in economic lifespan of trees caused by the reduction in bark consumption. Tocompensate the yield loss due to lowering the intensity, 2-Chloroethylphosponic acid(ethephon) is used as a yield stimulant in LIH to enhance the yield per tapping. Allcommercial formulations of ethephon available in Sri Lanka have been water based.Although such formulations have an advantage in preparing different dilutions by mixingwith water, their long term effectiveness in field application are often questionable. A new oilbased formulation (Motex plus) has been introduced to Sri Lanka and therefore, the studyrecorded here was focused to assess its effectiveness in application of LIH.

Performance of three low intensity systems recommended in Sri Lanka i.e. S/2 d3 (half spiralbased once in three days harvesting), S/2 d4 (half spiral based once in four days harvesting),and S/4 d3 (quarter spiral based once in three days harvesting) was tested with application of2.5% Motex Plus, every two months interval except during wintering, monthly and every twoweeks intervals, respectively together with S/2 d2 (half spiral based once in two daysharvesting) system for comparison. Dry rubber content of latex in LIH systems were above35% whilst it was about 33% in S/2 d2 system. Yield per tree per year in S/2 d3, S/2 d4 andS/4 d3 systems were 5.69 kg, 5.48 kg and 6.19 kg, respectively showing a slight higher yieldover the S/2 d2 system. Therefore potential reduction in the dose of oil based formulation isalso discussed. Number of trees affected with tapping panel dryness was comparably lower inLIH systems. Although the bark consumption per tapping was slightly higher in LIH systems,overall bark consumption has dramatically been reduced due to lesser number of tappingdays.