I'm not familiar with what they are using to spray for the Zika virus mosquitoes. However, I have done vector control spraying in California and in Arizona. Typically, the amount of chemical used is very small. an ounce per acre average. (I would carry around 25 gallons to cover an area of many square miles.) We fly at a height of around 400 feet. The good thing about the design of the mosquito is they are easy to kill so therefore require a minute particle to do the job. The chemical is distributed in a manner that the percentage of droplets that actually reach the ground are negligible. Vector control is normally done at dusk when mosquitoes are most active, and bees are in their hives. Whenever I flew vector jobs, we always checked for bees in the area. Including the downwind area for three miles. Apiaries and -registered- bee yards were notified before hand, and there was always a notice posted in the previous day's paper. Vector control operations are very expensive, they are not conducted haphazardly or without good cause. Generally the trigger is only pulled when the mosquito population reaches a threshold determined to be hazardous or having a negative impact on the populace, this includes economical impact as it applies to livestock and probably tourism depending on where you are I guess, or disease such as West Nile is found in samples taken throughout the region. I have, on several occasions dispersed larvacide in areas of standing water such as marsh lands, run off area's and fallow farmlands. I know many folks view these operations as greedy, selfish, evil, men trying to kill the world and cause the next several generations to be born with horrendous defects, etc? That is not the case at all. Hundreds of man hours, extensive research, and tons of documentation go into each and every vector control evolution. I know a lady who lost her Grandfather to West Nile. I've read reports of infants and children being killed or permanently disabled by west nile. I've read history where herds of livestock were literally driven mad by swarms of mosquitoes. I have never seen any credible information of negative effects on humans or anything else resulting from vector control operations. I will assume there have been bee kills, though I have not seen it proven, only heard about it. I find it difficult to believe given the timing of applications (Dusk to dark) the amount of chemical used and the manner in which it is disbursed that it would be enough to kill an entire hive of otherwise healthy bees. I am not saying it hasn't or couldn't happen, I just have never seen it proven. I tend to think it all falls into the liberal invented hysteria driven by those who want to blame Monsanto and GMO's and crop dusters for everything from "Climate change" to their kids' bad grades. Mosquitoes are capable of causing real damage. Most of us are unaware of that fact because we've lived under a blanket of health and security where those things haven't approached us. DDT was a chemical that was banned because a bunch of folks said it was killing birds and causing their eggs to fail. A claim found to be absolutely false by the way? DDT was used extensively. Admittedly more than it probably should have been, but it likely saved thousands of lives. The poorer countries like the Philippines for example suffered greatly when the use of DDT was halted. If there is concern in your area about these operations, I highly recommend contacting your county Vector Control office or Agriculture commissioner. Ask to visit their site, ask questions and explain your concerns. I am confident they would be happy to to provide you with any information you would like. Right now, we have very few tools in our box to combat things like mosquitoes. We are very restricted from using most of those tools simply because of a skewed public perspective that is in many ways ill informed (lied to). Until something better comes along, like the genetically selected (not modified) mosquito which has met with uninformed and hysterical public outcry, or something else, that people will certainly freak out about, we are stuck with what we have.