I would recommend against treating for worms unless a high load of a specific parasite is found by fecal sample- that needs to be addressed. Prophylactic treating for worms is not a good idea. It is sometimes done in a situation where there is a large colony of tortoises living together and constant reinfection is inevitable. But for a single tortoise, or even small number, the medication used also kills beneficial gut flora used to aid digestion and metabolism in a tortoise, so I would only do when necessary. Additionally some of the common "parasites" are considered beneficial to tortoises in small concentrations.
If you do need to treat, Panacur is the drug of choice for the more common nematodes in all species of tortoise. Pumpkin has no effect as far as a wormer.