The risk of getting malaria is related to the number of people who have malaria. In countries that have eradicated or greatly reduced malaria, better treatment has been of paramount importance. A little thought will show why better treatment of malaria is more important than mosquito control. A single malaria infection, if untreated, can last in a human for more than a year. If you kill the mosquitoes but don't treat the people, you have to eradicate ALL the mosquitoes for more than a year.
Total eradication is basically impossible at an acceptable environmental cost.
On the other hand, you could eradicate malaria by treating all the people for about a month. We have had outbreaks of malaria in Australia in the past, and we still have plenty of mosquitoes that can transmit malaria. An increased population density and a trend towards more outdoor living are factors that ought to make malaria more prevalent, and yet we have been officially malaria-free since 1981. The reason we no longer have malaria in northern Australia is an example of the effectiveness of prompt treatment. It takes about 10 days after you get sick from malaria before the gametocytes mature enough to infect mosquitoes.