"Why are Mosquitoes swarming us after you spray?"
It’s the type of question I never like to hear…and worse when it’s coming from a long time customer. “Lee, we’ve been with you for four years and never have we seen the mosquitoes this bad. Did you change something? Please come out for a re-spray. Thx!”
This spring did present – and continues to present – a different challenge as in previous years. A warmer than expected winter…a delayed spring brought about a swarm of mosquitoes. And it’s not in the usual sequence that one might expect. So, after one too many callbacks from customers, I reached out to my pesticide manufacturing rep from Bayer for some help. He in turn put me on the phone with Kurt Vandock, Bayer’s head of Vector Control. In addition to his work at Bayer, Vandock is an Army Reserve Colonel who is responsible for protecting our troops overseas in the Middle East . The man is a walking encyclopedia. He also has access to a virtual wealth of scientific data from around the world and can speak eloquently on any region – its peculiarities, native insects and the challenges they present.
After describing my concerns, and a series of questions, Vandock explained the issue in a nutshell. In the six weeks leading up to now, New England has experienced a slow beginning to spring. Coming out of a warmer than expected winter, we were met with brown earth for much of March and April. For mosquitoes, this meant not hatching from eggs during their normal cycle of life; and hanging out longer, waiting for a flood.
The particular genus in question is the Culex https://en.wikipedia.org/wiki/Culex. Culex is one of three genera in this region (Aedes and Anopheles being the others). Known mostly as a wetlands mosquito, the Culex female will lay its eggs in rafts of 300 or more. Typically, the egg hardens quickly and larvae will hatch from it at the first introduction of water. But this year, the water didn’t happen in normal sequence and this allowed the eggs to harden and wait out a long time period of dryness. While doing so, the females continued to lay even more rafts of eggs…and finally the wet weather hit. Like a flood during a 9 days period of rain, sun, rain and more rain.
So when the eggs hatched, the larvae stage was shortened and mosquitoes emerged en masse. And with no vegetation to speak of on the ground, they “retreated” higher than normal into the trees. Remember that mosquitoes mainly live off of plant nectar. Males only live for a week or so. The females (2-6 weeks) only bite when they need a blood meal for procreation. And that generally happens when we go outside in the early evening for that after dinner coffee on the back deck. [Fun fact – there are 47 different varieties of mosquitoes in Mass and New Hampshire]
As one customer described it to me – “it was like the Battle of the Midway; the way they were dive-bombing us.” Vandock even used that same term – divebombing - to describe the action. Mosquitoes were diving from 25-50 feet above ground down to the target (you).
So we would respray, but there was still little green out there. We would cover a plant, but after it bloomed into full growth, the result was a coverage of less than 20% over the leaf. Another two to three weeks before we sprayed again meant that a mosquito or tick could successfully navigate itself around with little threat of rubbing against the dried pesticide.
So, our solution was simple. Spray higher into the trees (in addition to the normal bushes, brush and eye level vegetation); spray into soffits around a house and concentrate on the north side of everything. Because we are so far north of the Equator, the north side of houses, trees and bushes are more shaded and cooler in New England. That’s where mosquitoes and ticks like to hang out. To date, the strategy seems to be working. Vandock pointed out that as foliage returns (as it is now) the issue of swarms of mosquitoes will lessen significantly. The product will be able to adhere to leaves and grass better (there is more of it) and as best as we can expect, it will return to a more “normal” normal. In using the product we use now, I’ve seen a much better overall control. And as the weeks go on, we’ll have much better results as the populations of mosquitoes die down. Plus, we’re adding a new weapon to our arsenal – the In2Care mosquito trap. For more information on that, give us a call.
So, keep those lawns mowed, and the toys picked up. No standing water. And with our regular service throughout the summer and fall, we should have a much calmer and more enjoyable experience being outdoors. Lord knows we need a break from all the other things going on in the world!