I've been doing some reading on this, and here's a snippet from some articles I found...
"Mosquitoes do not carry coronavirus," said Dr. Ned Walker, a professor of microbiology and entomology at Michigan State University. "The coronavirus just doesn't infect mosquitoes at all. It doesn't have the capacity to make the infection in the mosquito, and so for that reason if it can't participate in that kind of a transmission cycle."
That's consistent with other related viruses.
"SARS and MERS which are also coronaviruses are not carried by mosquitoes either," explained Walker.