Prevalence of Mosaic and Chlorotic Streak Diseases in the Sugarcane of Puerto Rico

Abstract

One of the problems facing sugarcane growers in Puerto Rico is the presence of sugarcane diseases such as mosaic and chlorotic streak. A general survey of the cane fields was conducted to determine the abundance of these diseases in Puerto Rico. It was observed that mosaic was abundant in the east-central as well as the southeastern part of the Island. The abundance of mosaic in that portion of the Island can be attributed to an increase in the cultivation of the very susceptible variety B. 34104. Although this variety is now being replaced by others, some of those being propagated in new plantings are susceptible to the disease. B. 34104 is still a menace to effective sugarcane growth in the areas where it has not been completely eradicated. Another factor that helps distribute the disease is the transportation of diseased seed to be planted in places where the disease is not found. Comparing the present mosaic situation with that in 1918, when the industry was on the verge of a complete collapse, we find that the areas that now appear to be relatively free from the disease are the ones that were more severely affected in the past. Chlorotic streak disease is also present in Puerto Rico, being more abundant in the northern part of the Island. Its presence is most predominant in the rainy regions of the Island north of the divide from Mayagüez to Humacao. Probably the vector transmitting the disease is more effective in this area.