What Duolingo score do you need for Colorado State University?

The Graduate School page says official scores must come directly from the testing agency, must have been taken within two years before admission, and that photocopies are not accepted. Neither page sets Duolingo subscores. The Graduate School does not accept IELTS General Training, the IELTS Indicator or iTEP. Neither page says anything about teaching assistantships.

For comparison, the same pages set IELTS Academic at 6.0 for undergraduate direct admission and 6.5 for graduate admission, with the Graduate School accepting the IELTS One Skill Retake.

The undergraduate page says you will be considered for conditional admission if you meet CSU's academic standards but have not sent a qualifying TOEFL, IELTS or Duolingo score. Conditionally admitted students enrol in CSU's Intensive English Program until they finish the Academic English Program or reach the required score. Finishing the IEP also counts as proof of English. The graduate page lists no conditional route.

Requirements vary by programme and change between admissions cycles. The score that binds you is the one on your Colorado State programme page and in your offer letter, so check it there before you book a test.