| August 2003. Dieback of mature mangoes in the Sindh Province of Pakistan. Gum is seen extruding from the branches and trunk, and branches die. It is not clear from the photos as to the symptoms and possible cause, but Pink disease caused by the fungus, Corticium salmonicolor, was suggested.
A similar condition was described from Samoa in the early 1980s, but no cause was identified.
On rubber, Pink disease occurs mostly on branch junctions, and sometimes a little further up. The early symptoms are the whitish growth on the bark, which turn pink as disease advances. Bordeaux paste works well at this stage. The paste is applied on the bark after scraping off the fungal growth. Application of the paste should extend well beyond the visibly infected portions of the bark. The scraper and other tools should not be used on healthy trees for any reason! Dithane M45 (mancozeb) in a paste form with inert clays (china clay, etc.) can also work well.
The success in controlling Pink disease is its early identification. In prevalent areas and in susceptible clones it might be worthwhile to apply the paste in all branch-junctions in the whole plantation, as a prophylactic.
If one begins to see leaves losing their shine, or drooping, it is too late for any control measures, other than to cut off the infected branch and limit the spread to other branches/trees. |
