Mosquito borne disease is a complicated issue and consequently there is plenty of confusing and misleading information.
First, Larvicides are highly effective although they should be used in combination with a multi prong eradication program. Larvae are relatively easy to kill. Eliminating airborne insects through fogging is much more difficult. And eliminating standing water sources when possible is a given.
Secondly, there is no scientific basis whatsoever for the claim that a larvicide is responsible for the outbreak of microcephaly. As commonly happens in situations like this, non-scientists who do not distinguish between causation and correlation instigate unfounded alarm. In this case, the larvicide pyriproxyfen in not the culprit.
Third, Malaria is the number one infectious disease killer world wide. It kills between one and two million people every year - most of them children. Without the proper use of larvicides this toll would be far higher.
Fourth, Zika is no threat to most persons. In fact, most people infected will never manifest any symptoms. Others may become ill but will quickly recover. It is a serious threat only to women of child bearing age who may become pregnant in a region where they could be potentially be bitten by a vector.
And finally, Zika is a flavivirus, one of a family of similar viruses responsible for Dengue, Yellow Fever, and West Nile. It will not spread epidemically in the US just as those other flavivirus diseases have not due to simple containment measures not always available int he third world.