This current review attempts to prevent interest in other subjects from eclipsing interest in cadang-cadang.
Disappointingly, the water-soaked spots are not unique to coconuts affected by cadang-cadang.
Moreover, there is no general agreement on the characteristic of the water-soaked spot; thus Nagaraj (1967) enumerated many kinds of water-soaked spots, even among plants outside the cadang-cadang area, which differ from each other only in their measurement.
Some of the major theories on the probable cause of cadang-cadang were (1) virus, (2) soil or nutritional imbalance, (3) physical stress such as typhoons, (4) microorganisms such as fungi, bacteria, and nematodes, (5) phytotoximia due to secretions of aphids or Marasmius sp.
Moreover, Maramoroseh (1961) mentioned the belief of farmers that typhoon, eruption of Mayon Volcano, and introduction of cattle herd to coconut groves as contributing factors in the spread of cadang-cadang.
The course of spread was traced by Celino (1947), as follows: "The cadang-cadang disease was first observed in 1928 just outside the Estate of the Agusan Coconut Company (now Gancayno Estate) on San Miguel Island, Tobacco, Albay.
Zelasny (1979) made another geographical survey, especially in the border areas of cadang-cadang occurrence such as Quezon, Camarines Norte, Western Samar, Eastern Samar, and Leyte.
1960) and Fajardo (1953) were compared with the present distribution of cadang-cadang, it became clear that the area containing the disease has not increased significantly during the last 20 to 30 years.
These observations suggest that cadang-cadang is endemic to Bicol and adjacent areas.
On August 12 or after an incubation period of 77 days, one of the inoculated seedlings showed symptoms of cadang-cadang.
At the end of his study, he reported that "the expert is of the opinion based upon these negative results and other observations, that it is premature to state that cadang-cadang is a virus disease.