cadangcadang

Cadangcadang, or coconut cadang-cadang disease, is a palm disease of the coconut tree (Cocos nucifera) caused by the coconut cadang-cadang viroid (CCCVd). It was first reported in coconut-growing regions of the Philippines in the early 20th century and has since been identified in several tropical coconut-producing areas. The disease is notable for its slow progression and potential to cause widespread crown decline and death of affected trees.

Symptoms typically begin with yellowing and die-back of older fronds, followed by gradual crown decline. Leaf blades may show mottling and necrosis, with progressive reduction in vigor and nut production. Infected trees eventually fail to produce normally and may die within a few years after symptoms appear. The disease is usually more noticeable in older, stressed trees but can affect both seedling and mature palms.

Etiology and transmission: Cadangcadang is caused by the coconut cadang-cadang viroid, a small circular RNA agent that replicates in plant tissue. The primary mode of spread is through infected planting material, including palm seeds and other vegetative propagules. Natural vectors are not well established, and there is no chemical cure. Human activities, such as movement of contaminated planting material between regions, play a major role in geographic spread. Sanitation and strict material certification are key control measures.

Distribution and impact: The disease poses a significant threat to coconut production in affected regions, with potential yield losses and impacts on smallholders and local economies. Areas free of CCCVd usually require stringent quarantine and certification programs to prevent introduction.

Management and prevention: Current control relies on prevention, roguing of infected trees, movement controls of planting material, and use of certified, disease-free stock. Diagnostic methods include molecular assays to detect CCCVd in planting material and trees. There is no cure for established infections, so early detection and quarantine are essential.