Latex analysis: A latex microdiagnosis was carried out once a year between August and January taking into account the dry rubber rate and the sucrose, inorganic phosphorus and thiol contents. To determine the dry rate (%), a latex sample was weighed before and after drying in oven at 80°C for 24 h. The sucrose, the inorganic phosphorus and the reduced thiol groupings were measured on the clear serum called TCA-serum (trichloroacetic acid) that is obtained after latex acid coagulation, respectively, by the Ashwell anthrone method (1957), the Taussky and Shorr molybdate ammonium method (1953) and the Boyne and Ellman acid dinitro-dithio-dibenzoic (DTNB) method (1972). The results are stated in mmole per litre of latex (mM/l).