Hevea brasiliensis (Muell Arg.) undergoes annual leaf shedding commonly known as wintering. The wintering period in the traditional rubber growing areas in the Wet Zone of Sri Lanka is from December to February followed by flowering and flushing in March. Tapping rest during wintering is recommended in certain countries while in some other countries year round tapping is practiced. In Sri Lanka, until early1970s winter resting was practiced, but this is not being practiced at present. Incidence of tapping panel dryness appears to be high with currently recommended clones and hence the objective of the present study was to investigate on the effect of winter resting on the annual yield and tapping panel dryness in rubber clones. Experimental trials were conducted for two consecutive years (2018 and 2019) with three clones viz., RRIC 100, RRIC 121 and RRISL 203 at the Substation of RRISL at Kuruwita in Ratnapura district. Treatments tested were continued tapping with no winter rest (T1), resting during the wintering period (T2) and once in six days tapping during the wintering period (T3). Trees were tapped at S/2d3(once in three days) intensity. Data were collected on latex volume, bark consumption and TPD incidences. Results for two years showed higher g/t/t/ in all three clones when rested during the wintering period in both years as compared to those with no winter rest. Significantly higher annual total crop (kg) was recorded for T1 when compared to T2 in all three clones for both years. Though total number of partially and totally dry trees of winter rested trees of clones RRIC 100 and RRIC 121 were low, the differences were not significant. In terms of profits obtained as indicated by economic analysis, resting the trees during wintering resulted in the highest profits, followed by d6 tapping during the same period. Winter rest should be tested for a longer duration (4-5 years) for all the clones recommended at present that are vulnerable to tapping panel dryness.

Maintaining the tapping quality in rubber fields is the key requirement to obtain potential yield with minimum harm to the tree. It also determines productivity and the economical lifespan of 30 years and sustainable rubber industry. The length of the tapping cut, the depth, the thickness of the bark shaving, and the slope of the tapping cut are the main factors determining the tapping quality. Use of a stencil according to the intended tapping frequency, i.e. d2, d3, d4, etc., to mark the guidelines to maintain the proper tapping angle of 30 degrees to the horizontal, and the bark consumption allowed for one year, are all equally contribute to maintaining the tapping quality. About 5000 ha. was surveyed to assert the tapping quality and to make recommendations. The average bark consumption rate per panel was four years deviating from recommended six years under d2 tapping. The monitory loss per hectare under this bark consumption rate is Rs.2.5 million at a productivity level of 1000 kg/ha/y and Rs.350.00 per kg of rubber. Trees affected by tapping panel dryness varied and was over 70% in some extreme cases. Introducing a quarter cut on the upper opposite panel of the tree ceased the situation to a greater extent.