Source Year: 2000

Experiments were conducted at the Dartonfield estate, Sri Lanka to determine the effect of fungicide sprays on seed production of rubber(Hevea brasiliensis). Twenty clearings were selected aged from 9-19 years and including the clones PB 86, RRIC 110, RRIC 121, RRIC 130 and PB 28/59. Three clearings consisted of mixed clones. A mixture of thiovit (80;wettable sulfur) and copper oxychloride, each at a concentration of 5g/litre, were sprayed at 10-12 day intervals throughout the flowering period. The results showed that a positive effect of spraying was only recorded in 18-year-old PB 86 clearings where the seed production was more than double in sprayed compared with unsprayed clearings. There was no seed production in clearings of RRIC 121, RRIC 110 or PB 28/56, and only a small quantity of seeds was collected from RRIC 130. The seed production of mixed clonal clearings was relatively higher than individual clone clearings although fewer seeds were produced after spraying.