Have you talked with your dev team to understand why they don’t (or don’t want to) open Asana and update their tasks ? As @Sebastian_Paasch said, could you write more detailson the issue?
Explaining why you want to use Asana is very important and maybe you’ve already done that, but you should also daily accompany them to show how to use Asana and the added value of Asana. When you’ll have convinced one of them, the others will follow and believe also in Asana.
@Sebastian_Paasch has written a great topic on Asana implementation with many advices: