There was a potato blight, but a deliberate British policy forced the continued export of the food the Irish needed to make up for the shortfall of the potato harvest. Thus, widespread starvation. Some say that this was as an attempt to eliminate a portion of the Irish population.
Yes, it was to reduce the Irish population to where the English could take over the land.
It was genocide.
Check out the Bengal Famine of 1943. The British caused it to be so much worse.
https://en.wikipedia.org/wiki/Bengal_famine_of_1943