Worship of Lord Ganesha is performed every Tuesday. So many things are offered to Lord Ganesha in worship, but Dubo is of special importance. His worship is not complete without dubo. Basil is considered to be a form of Vishnu. But Ganeshji dislikes Tulsi. The use of Tulsi in Ganesh Pujan is forbidden. There is a story about Dubois. According to legend, in ancient times there was a demon named Analasur. He had spread terror on earth and in heaven. Analasura swallowed the sage and the common people alive.
Frightened by the demon, Devraj went to pray to Lord Mahadev under all the deities and chief sages, including Indra. Ganeshji went to fight Analasur. The demon tried to swallow him but instead Ganeshji swallowed the demon. After swallowing the demon, Ganeshji’s stomach burned badly. Many measures were taken and the stomach irritation did not subside. Then the sage Kashyap made a knot of 21 munto dubo and gave it to Ganesh to eat. After eating dubo, Ganeshji’s pain subsided. Since then, the tradition of offering dubo to Sriganesha has started.
There is also a story about why Tulsi should not be offered to Ganeshji.
According to the story, in ancient times, Tulsi had prayed for marriage with Ganeshji. But Ganeshji did not agree. An angry Tulsi cursed Ganeshji to have two marriages. Ganeshji also got angry and cursed that your marriage should be with an asura.
After hearing the curse of marrying a demon, Tulsi apologized to Ganeshji. Then Ganeshji said that your marriage will be with Shankhachurna but you will be dear to Lord Vishnu and will give salvation to people in Kali Yuga but it is inauspicious to offer you while worshiping me.