A tough nut to crack: PC in tropical America
ASD is committed to the search for sustainable long-term solutions to the different phytosanitary problems of oil palm, particularly in the American tropics. Spear rot (or pudrición del cogollo-PC) is one of those conditions that has been prodigious in escaping a permanent, practical and inexpensive solution for the producers.
The frontal attack on any pathogen or pathogens that could be involved as causes of this disorder has so far been unsuccessful, and the knowledge gathered thus far in more than 30 years of searching for a solution makes us assume that this will come through a combination of good agronomic practices and the use of resistant or tolerant varieties.
ASD has worked actively in the two fields referred to above. First, we have provided important evidence that there is a clear predisposition to the problem when the root system of the plant is weakened by adverse conditions in the soil for its proper development (poor aeration or severe droughts accompanied by high temperatures, for example). In this same line of research we have found that timely, sufficient and balanced nutrition is vital to preventing the spear rot problem or attenuating its severity. For this purpose, the production potential (environmental conditions) of each particular site must be taken into consideration, to keep the plant from producing quantities of fruit above what a certain environment can sustainably support.
ASD has been a pioneer in the search for tolerance or genetic resistance, developing the idea that tolerance to stress in general (hydric stress or waterlogging, for example), is related to spear rot tolerance. This hypothesis is currently being tested with the planting of various stress-tolerant genotypes in field experiments in several countries and environments where spear rot is a serious problem (Fig. 1).
ASD has also made two OxG hybrids (Amazonas and Bruca: see ASD in a Nutshell, No. 1) available to palm growers, with the intention of contributing to solving the spear rot problem in tropical America.