Spear rot
Spear rot is a fungus infection of the spear leaf or the palm growing point 1, 2. Spear rot usually occurs when the palm is already damaged, for example by insects. Preventing insect attacks by doing good maintenance in the plantation is the best way to prevent spear rot.
The symptoms of spear rot are a dead or rotting spear leaf (see: Figure 13 and Figure 14). There is currently no cure for spear rot. If the whole growing point is killed by the fungus, then the palm will eventually die. In less severe cases, the growing point can recover.
Crown disease
Crown disease mainly attacks young palms (1—4 years after planting) but has been known to persist for up to 10 years. It is still unclear what the cause of crown disease is, but it is clear that some planting materials are more susceptible than others. Buying good planting material and providing sufficient potassium (K), magnesium (Mg) and boron (B) are the best ways to prevent crown disease 2.
Crown disease can be recognised by a typical bending of the leaves, somewhere in the middle. At the point of bending, leaflets are absent or very small. The palm looks very dense, like a pile of leaves. In very severe cases, all the new leaves become affected and the palm growth and yield in the first years is seriously reduced.
Bud rot (Pudrición de Cogollo)
Bud rot (Pudrición de Cogollo or PC in Spanish) is a devastating disease which is found mostly in South and Central America, and sometimes in Africa. The disease starts with the yellowing of the youngest fronds, and a rotting of the spear leaf. In extreme cases, the rot moves down into the growing point of the palm (the ‘heart’, hence the Spanish name which means ‘heart rot’) and the palm may die. If the palm survives, recovery can take months or even years.
Bud rot can be extremely devastating. The disease has wiped out entire plantations, with tens of thousands of hectares being lost within a few years. Despite intensive research, the cause of bud rot remains unknown. Several fungi as well as abiotic factors have been pointed at.
As a management option, it has been common practice to cut away diseased tissue in the early stage of the disease, and to destroy palms that are more severely affected 3. However, these measures have not prevented the destruction of entire plantations, and overly fast removal of palms might in some cases even have contributed to the severity of the destruction.
Bud rot has not (yet) been found in Southeast Asia.
References
- ↑ I.R. Rankine, T.H. Fairhurst, Field Handbook: Oil Palm Series, Volume 3 – Mature, second ed., Potash & Phosphate Institute (PPI), Singapore, 1999.
- ↑ 2.0 2.1 R.H.V. Corley, P.B. Tinker, The Oil Palm, fourth ed., Blackwell Science, Oxford, UK, 2003.
- ↑ G.A. Torres, G.A. Sarria, S. Salcedo, F. Varón, H.A. Aya, J.G. Ariza, L. Morales, G. Martínez, Opciones de manejo de la Pudrición del cogollo (PC) de la Palma de aceite en áreas de baja incidencia de la enfermedad PALMAS, 29 (2008) 63—72.
Acknowledgements
The material from Other diseases is sourced from Smallholder Oil Palm Handbook and put together by Lotte Suzanne Woittiez (Wageningen Universit) and Haryono Sadikin, Sri Turhina, Hidayat Dani, Tri Purba Dukan, and Hans Smit (SNV) in August 2016. See Module 5: Pests and Diseases for more information.
