The Bodhi tree at Bodh Gaya, which is sacred to millions the world over since Lord Buddha attained enlightenment there about 2,550 years ago, is threatened by an unknown disease.
"Hundreds of fresh leaves of the holy tree are falling off daily like never before. Something is wrong with the tree," said a monk at the Mahabodhi temple in Bodh Gaya, about 100 km from Bihar's state capital Patna.
The Bodhi tree grew from the original banyan tree under which the Buddha attained enlightenment. It stands behind the Mahabodhi temple. In 2002, UNESCO declared the Mahabodhi temple a World Heritage Site.
Sources in Bodh Gaya said plant scientist AK Singh had suggested some corrective measures after examining the tree.
"He had reportedly warned that the tree is undernourished and lacks required moisture level around the roots," a source said.
But Gaya district officials are reluctant to speak in detail on what afflicts the tree. "AK Singh had suggested some measures like additional nutrients for the tree," said Gaya District Magistrate Jitendra Srivastava.
Last week, the Gaya administration again sought the help of AK Singh to check the rapid fall of fresh leaves.
Only two years ago scientists had saved the Bodhi tree from a disease, when the leaves started turning black and dull.
"The tree grew new leaves after three years of treatment by scientists," an official said.
Hundreds of Buddhist pilgrims from around the world carry back leaves from the tree.
Last year, miscreants cut off a branch of the tree.
According to an official of the Mahabodhi temple, the Bodhi tree was the sixth regeneration of the original banyan tree.