Weligama Coconut Leaf Wilt Disease (WCLWD) is a non-lethal, but debilitating phytoplasma disease found in coconut palms in Sri Lanka which is confined to the Southern Province of the country, well-away from the major coconut growing area. If it spreads to the major coconut growing area, it might severely damage the coconut industry in Sri Lanka. Government commenced a disease control program to eradicate the disease and, more importantly to prevent spreading of the disease to major coconut growing areas. The major constraint in this program is the lack of an accurate and reliable method for identifying affected palms. Visual symptoms are used to identify the affected palms for removal, yet growers are not always convinced of the method of resisting palm removal. This poses a serious threat to the implementation of the disease control program. Although a Nested-PCR-based disease diagnosis was established earlier, the detection rate and reliability need further improvements. Therefore, an urgent necessity for a more reliable disease detection method has arisen. In the current study, a Real-Time Polymerase Chain Reaction (qPCR) powered by a pair of primers and a probe designed from the published partial sequences of the WCLWD phytoplasma was validated with 202 coconut samples and a detection rate of above 95% was achieved. This newly established detection system was highly reliable and a way forward for controlling the WCLWD disease in Sri Lanka.

Coconut is one of the most important small holder crops worldwide. Conservation of coconut as seeds or field gene banks is not effective due to a range of limitations. Cryopreservation, which is the conservation of living propagules at very low temperature (-196ºC), is the only method available currently for the long-term conservation of germplasm for problem plant species such as recalcitrant and vegetatively propagated plant species. This review summarizes different cryopreservation techniques that have been published from 1984 until the present in relation to different coconut material; it includes a brief discussion about short and medium-term cryopreservation before describing long-term preservation. It discusses factors affecting the process and success of cryopreservation, such as selection of plant material, pre-culture of tissues, osmoprotection, dehydration, cryo-storage, thawing and post-culturing of tissues, and finally to plants. The review also describes histological and ultra-structural studies on and the use of molecular markers to assess genetic stability after cryopreservation. Limitations and future directions related to coconut cryopreservation are discussed. Additional experiments are identified that will need to be undertaken to improve our understanding of the different cryopreservation methods.