If I had one wish and I wished all mosquitos would die...

Birds eat them. Birds also eat fruit / berries. They then poop the seed - rich in a poop surrounding and so a new plant grows. No mosquitoes, fewer birds, fewer plants, less co2 / o2 - death.

Oh, and Bill gates is way ahead of you.

My worry is the law of unintended consequences. Kind of like Mao killing off sparrows in China which in turn led to the great famine.

Well mosquitoes are an abundant food source for them, they can't simply "find something else to eat". It's like saying if humans had to stop eating fruit (or some other commonly consumed food). And how some people stated, no mosquitoes means less animals. Mosquitoes, to a lot of people's surprises, are vital for the environment in unlikely ways:

1. They control overpopulation. Because of how mosquitoes are carriers of many diseases, they spread them to other animals. This makes sure that a single species will not destroy an environment by overpopulating (maybe not for humans).

2. They are an important food source. Birds, bats, fish, bugs, and all sorts of other animals eat mosquitoes for survival. During migration, birds depend on mosquitoes heavily because they are in large numbers. Mosquitoes larvae are also eaten.

3. The larvae of mosquitoes feed on waste material and debris in the water, acting as a filtration.

4. Male mosquitoes are important pollinators for flowers.*

However pesky and annoying they may be, mosquitoes are important to the ecosystem. A lot of things would go wrong without them.

*The mosquitoes that suck your blood are only females. They suck on blood for the iron in the blood for their eggs. Male mosquitoes do not feed on blood and instead feed on nectar.