Strictly speaking, if you are in a grammar class, you will say, "There is an apple and there are two pears." Or like fdmaxey and Allen put it above.
In conversational or even business written, it is perfectly alright to say "There is an apple and two pears." You are, basically, not mentioning some words.
Put it another way, if there were two apples and three pears you will say, "There are two apples and three pears," even though you are saying it the same way.
Haha... lots of differences between what is grammatically correct and how you can also say it in real life based on the culture.