http://www.apsnet.org/online/feature/citruscanker/

Take note: Calamondins, kumquats are highly resistant to canker, followed by satsumas and other mandarins.

The most susceptible are grapefruits and key limes. The trifoliate rootstocks are also susceptible.

If I remember correctly, I have never seen pummelos that are infected with canker while I was in the Philippines. So perhaps pummelos are one hope for hydrizing resistance to grapefruits. Perhaps the Oro blanco and Melogold have inherited this trait, it would be interesting to know and someone here could enlighten us about the latest research. I am not sure about the resistance of pummelos since my observations are only based from my rusty memory, more than 25 years ago. But I do remember canker infected leaves and fruits of a lot of other citruses, still they are producing, and people are buying the fruits nonetheless.

My experience is that with Calamondins, they do get canker, but only superficially and the yield is not impacted as much. I am not really worried about canker, since the only citruses that I like the best are Calamondins and mandarins and are resistant.

It would be a disaster for the California citrus industry, however, so I will do my part to help in preventing the spread of the disease.