Thresholds of annoyance have been established in Maryland to guide control operations. The threshold for traps using carbon dioxide as an attractant is one hundred female mosquitoes per day. The threshold for landing rate counts is five mosquitoes in two minutes. Mosquito populations above these thresholds warrant control, for those below the threshold no control is authorized. These thresholds are established for pest control only and more liberal control is warranted if mosquito-borne disease threatens public health.
Larval surveillance is carried out by visual inspection of containers and by dipping.
The larvae are easily disturbed by vibration or shadows passing over their surface, and either event will send the larvae to the bottom of the container where they are difficult to find. It is best to carefully approach a suspect breeding site and look into it without casting a shadow. Control of Tiger Mosquitoes in Maryland Control of tiger mosquitoes by conventional methods in the United States has proven to be difficult and generally ineffective. The impact of several predators and parasites as biological control agents of larvae has been investigated. In general, these agents have been found to play a small role in regulating the number of mosquitoes but not a significant impact.