Dewa Sanzan: No Yudono-san bus in May?

I am hoping to visit Yudono-san in mid-May. But it looks like the Shonai bus service to Yudono-san from Tsuruoka has been cut back, and there are no buses to Yudonosan until 6/1:

http://www.shonaikotsu.jp/local_bus/time_table/t11_yudonosan.html

And the Yamagata bus is no longer stopping at Yudono-san:

http://www.shonaikotsu.jp/information/kaisei.html

Is this correct? If so, it is possible to take a taxi from Tamugimata to Yudono-san instead (and back)?

Why wrong? both links by official.
Until end of MAY not best car/hiking roads conditions by snow covered and low temp/strong winds usual.

And Tamugimata bus stop taxi no waiting.

Thank you for your reply. So it is impossible to visit Yudono-san until June?

I guess as you know, that there is no means only a rental car or taxi to go there in mid-May.

It is possible to worship the Yudonosan Jinjya Hongu from April 29 every year. However, because of natural disasters, the start has been postponed this year. Plan of the shrine of mid-May is not fixed.

Currently, it has been determined for that go in mid-May to Yudonosan Sanroujyo is located in front of Yudonosan Jinjya Hongu.
Yudonosan Sanroujyo
http://www.dewasanzan.jp/publics/index/77/ (Japanese)