April and May of this year demonstrated how challenging it is to predict the levels of mosquito activity. Mosquitoes go through four “stages” of life (eggs, larva, pupa and adult). In the first three stages, the mosquito lives on or in water and the fourth stage produces a flying, air breathing hungry insect. The females are then especially busy looking for a blood meal, which will provide protein to nourish their eggs.
Early in the season the BLSG field technicians were out sampling (using a dipping cup to scoop cups of water and count the larvae) the larva counts among 70 different sampling sites. By April 24 they were finding numerous locations with 20 to 100 larvae per cup; 20-100 larva per cup is considered high counts indicating likely large outbreaks of mosquitoes in 10 to 14 days. Where possible these sites were treated with larvicide by hand and boat. The rainfall in April was 5.83 inches (twice the April normal) coupled with a sizable snow pack coming off the mountains, so flooding was inevitable. Many, many acres of land in the Otter Creek watershed would be available for mosquito nesting. While the Brandon Leicester Salisbury Goshen Insect Control District has trapped and received reports of some mosquitoes, those samples and reports don’t reflect not the broadly based, “run to your car” swarms that might have been expected.
By mid-May the larvae counts were coming down. There were still pockets of high counts, but there were also a number of samplings with no larvae found. It is possible the lower-than-normal water temperatures (there was more rain and little sunshine in May) and/or the large quantity of water and therefore greater movement of the water contributed to the reduced larvae counts. For now, the lower larvae counts are encouraging and areas active with larvae are still being treated with larvicide.
At this time the mosquito larval count is low, but this can change quickly if conditions change. The BLSG technicians are currently setting adult mosquito traps to evaluate the current adult populations. These results are used to help determine where and when spraying is appropriate. Adulticide applications were made on May 30 and June 7, 11 and 12 based on the number of mosquitos trapped within the designated spray routes. Spray routes are posted online at BLSGmosquito.com under Public Notice by 3 p.m. each day spraying is planned. 
Editor’s note: Jay Michael is a member of the BLSG Insect Control District board.