How to label an arrow in a commutative diagram

Question

I'm writing my thesis using LaTeX. I need to add a commutative diagram with labels on arrows. Let me say that I'm writing my text in Italian using the babel package.

Here a minimal example to understand the problem:

\documentclass[oneside,italian]{book}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}

\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{tikz-cd}

\makeatother

\usepackage{babel}
\begin{document}
\begin{tikzcd} A \arrow[rd] \arrow[r, "\phi"] & B \\ 
                                              & C 
\end{tikzcd} 
\end{document}

The problem is that if I don't use the package babel the code doesn't create any errors. If I insert babel I get this message error:

Undefined control sequence.
... \arrow[r,"\phi"] & B \ & C \end{tikzcd}
The control sequence at the end of the top line of your error message was never \def'ed. If you have misspelled it (e.g., \hobx'), typeI' and the correct spelling (e.g., `I\hbox'). Otherwise just continue, and I'll forget about whatever was undefined.

Moreover, if I cancel the code "\phi" all works using babel or not. Any suggestion?

I've tried to upgrade the version of the package tikz-cd but nothing changes.