Dieback disease in neem can be nipped in the bud: FCRI study

HYDERABAD: Researchers at the Forest College and Research Institute (FCRI) in Mulugu have suggested certain plant management practices to protect neem trees affected by ‘twig blight’ and ‘dieback’ diseases.Laboratory studies were conducted at the institute, identifying the pathogen as Phomopsis azadirachtae. The institute developed management options by selecting infected trees in a small area.

In the past few years, neem trees (Azadirachta indica), commonly called ‘Indian Lilac’ have been encountering a great threat due to a destructive disease known as twig blight and dieback, in which woody plants were characterized by progressive death of twigs, branches, shoots or roots, starting at the tips.

The dieback of neem affects leaves, twigs and the inflorescence of neem trees of all ages and sizes. It causes almost always 100 per cent loss of fruit production in severely infected trees. This disease is more pronounced during August to December. The appearance of symptoms starts with the onset of the rainy season and becomes progressively severe in the latter part of the rainy season and early winter.

According to Jagadeesh Batthula, Assistant Professor, (Plant Protection), management operations should start from the nursery raising itself, as the pathogen is both seed-borne and seed-transmitted. During sowing, seed treatment with fungicides or biocontrol agents reduces the infection. At the seedling and sapling stage, prophylactic sprays of suitable fungicides like Carbandazim 2.5 g/lit or biocontrol agents like Trichoderma which can improve sapling health and impart resistance against diseases, can be used. He suggests pruning operations to be done with the help of an arborist, where diseased twigs are removed and burnt to stop further spread during the next season.

“Neem tree inherently is quite tolerant to the disease and has often been able to compensate the damage caused by fungus, even to fight back and survive the disease without any external intervention. Neem trees are strong enough to combat the damage caused by dieback. Diseases occur on trees seasonally with different severity rates because plant diseases are shifty enemies,” he opines.

MAKE THE FIRST MOVE
According to Jagadeesh Batthula, Assistant Prof,  management operations should start from the nursery raising itself, as the pathogen is both seed-borne and seed-transmitted.