Where I lived in southern New Jersey we had bats that worked the open field behind our house. As a result we had a lot less mosquitoes than our neighbor right across the street, so I had proof that bats can make a difference. But of course we still had some mosquitos, just not as many. So the bottom line is that bats will help. But getting them to set up your property as a feeding station is another thing. I have yet to discover why they pick one spot over another. On the property I now have, we get a bat feeding over our garden for about an hour most warm nights (bats here are solitary). But it doesn't
feed right across the street over an open 20 acre field. I'm not sure why my garden is more appealing. Bat houses don't work for our type of bat, but I learned that they sleep in dense tree
canopy. Thus I've purposely not removed that kind of trees that they like to call home.
Using bt in the wet areas will definitely cut down on adult mosquitoes. I use bt once a month in my bromeliads, plants that hold
water. In NJ, bt was used in the vernal ponds and marsh areas.
My mosquito water traps work the best. I intentionally set up mini ponds for female mosquitoes to deposit their eggs. I started out by using bt in these ponds, but have since changed to using small fish (mostly guppies). They eat all the mosquito larvae. I live where it doesn't freeze, thus the fish live year around. In your area they would die out in the winter.
