Report on the plant pathology mission SOCFINDO (oil palm), Indonesia, 21-29 February 2000

The Mata Pao, Bangun Bandar, Tanah Gambus and Aek Loba estates were visited, primarily to analyse the phytosanitary situation created by Basal Stem Rot (BSR). It is not currently possible to gain a clear picture of disease impact, as the parameters available (number of uprooted palms or number of living palms) underestimate the extent of the damage caused by BSR. It is therefore recommended that individual palm-by-palm observations be launched, with disease mapping using a scoring system proposed in this report. These observations will provide a clearer understanding, under the conditions studied, of the factors that speed up or slow down the spread of the disease. However, trends for the number of uprooted palms suggest that the disease is more serious in the third generation than in the second generation, but that BSR dynamics in the fourth generation could be less critical than expected. This needs to be seen in relation with the date when third generation foci appear, since they are all the more infectious for replantings the earlier they occur. The main factor limiting an assessment of the planting material, at least in terms of the time required, is the absence of an early selection test by artificial inoculation of the pathogen. Nevertheless, steps can be taken, based on results from the genetic trials, so as to eventually eliminate the sources of susceptibility to BSR. Various agronomic practices have been successively introduced, but it is difficult to assess their impact on BSR in the absence of adaptive trials to validate them. It has to be acknowledged that it takes a very long time to obtain results in such trials, especially when land preparation is involved. It is by analysing disease dispersion that new trials could be envisaged. The prospect of biological control is of interest to all plantation companies faced with the problem of rot diseases, notably because of the failure of any efficient and cost-effective chemical control. There are still only few results showing the sustainability of protection provided to a perennial crop such as rubber or oil palm. An experimental phase is therefore necessary before any mass production of Trichoderma. (Résumé d'auteur)