Scott Larzelere
Mosquito Control, Program Manager (Acting)
- [email protected]
- Main
- 410-841-5870
Midge (No-See-Ums) Suppression
About the Midge Suppression Pilot Program
The Maryland Department of Agriculture in conjunction with Maryland Department of Natural Resources established the Midge Suppression Pilot Program via Executive Order in 2017. The purpose of the pilot program is to test the feasibility of Back River midge control and determine the impact of Bacillus thuringiensis israelensis (Bti) in controlling midge populations in the area. The pilot program also aims to determine the most cost effective dosage and frequency of Bti treatments in the area.
What are midges?
Non-biting midge flies or chironomids commonly occur in inland and coastal natural and man-made bodies of water. These midges are commonly known as “blind mosquitoes” because they are mosquito-like but do not bite. Midges are also called “fuzzy bills” because of the male’s bushy antennae.
These aquatic insects are tolerant of a wide range of environmental conditions. Chironomid midges are found in swift moving streams, deep slow moving rivers, stagnant ditches, and in lakes and ponds that are rich in decomposing organic matter. The presence of certain chironomid midges is often used as an indicator of water quality. Bodies of water in urban and suburban areas are subjected to intensive human use through residential, recreational and agricultural activities. Through runoff, these ponds and lakes often become exceedingly rich in nutrients.
Consequently, the variety of organisms in such habitats is usually low with just a few pollution tolerant species developing large populations. Some species of chironomid midges that are tolerant of low dissolved oxygen conditions often are a major component of the bottom invertebrate organisms of urban and suburban lakes, ponds and storm water retention ponds. (Credit: North Carolina State Extension)
How are midges treated in this pilot program?
Bacillus thuringiensis israelensis (Bti) is applied by boat and/or helicopter using an apparatus designed specifically for midge control. Bti is a naturally occurring soil bacterium that has been demonstrated to be non-toxic to humans, mammals, birds, fish and most invertebrates.
Midge reporting map
Frequently asked questions
Midge suppression FAQs
In response to concerns from citizens and businesses in the Back River area, Governor Larry Hogan issued an Executive Order creating a midge supression pilot program directed by the Maryland Department of Agriculture (MDA) with Maryland Department of Natural Resources (DNR) in conjunction . The pilot program will be implemented this summer (2017) on the Back River in Baltimore County.
The objective of this pilot program is to test the feasibility of Back River midge control and determine the impact of Bacillus thuringiensis israelensis (Bti) in controlling midge populations in the area. The pilot program will also aim to determine the most cost effective dosage and frequency of Bti treatments in the area.
Staff from MDA and DNR have worked together to identify a 260-acre section of the Back River in Essex where midge populations have become a major nuisance.
Maryland Department of Natural Resources biologists will conduct larval sampling and continuous adult sampling using light traps. DNR will also track midge complaints in the area. For more information, contact Maryland Department of Natural Resources ([email protected] ).
The Maryland Department of Agriculture will manage the aquatic spray contract and issue spray notifications.
Non-biting midges are the common term used for Chironomid midges (Diptera: Chironomidae). Worldwide, chironomids are the most widely distributed and frequently the most abundant aquatic macroinvertebrate in freshwater aquatic environments. Some species are also found in brackish and marine water and in terrestrial biotypes. In lentic freshwater eutropic urban environments, the benthic larval stages often occur in huge assemblages and upon emergence, adult midges can be a problem to the general public and industry, even though they do not bite or transmit diseases.
Chironomid midges have four distinct life stages: egg, larva, pupa and adult. The larval stage develops through 4 instars in less than two weeks depending on species and conditions. As with most insects, temperature and food availability control the length of time required for completion of their life-cycle.
| Life Stage | Description |
|---|---|
| Eggs | Eggs are laid in mass on water or on firm, fixed objects along water edge. |
| Larvae | Hatched larvae develop in bottom of organic substrates where they feed upon algae, woody debris, detritus, macrophytes and invertebrates. |
| Pupae | Pupae rise to the water surface and emerge as adults. |
| Adults | Adults will live approximately 1 week depending upon the species and various biotic and abiotic factors. Males form swarms where they capture females for mating. |
| Typical mosquito | Chironomid midge |
|---|---|
| Uses its proboscis to bite. | Cannot bite. |
| Wings are longer than its body. | Wings are shorter than its body |
| Larvae develop in water | Larvae develop in mud and detritus on the bottom of lakes and ponds |
| May carry disease | Do not carry diseases |
The emergence and swarming of adult midges from aquatic habitats can create both nuisance and economic problems (Armitage et al 1995):
- Midges congregate in shady cool areas and deposit meconium or release eggmasses which stain surfaces. Adults can deface automobiles, walls, ceilings, curtains and other furnishings.
- They are attracted to light which can cause great discomfort in residential areas.
- Midges can be a problem for paint, paper, pharmaceutical and food processing industries where adults may contaminate final products.
- Economic loss to the hotel and tourism industry can be affected by nuisance swarms that may create stressful conditions for tourists (Anon., 1977).
- Accumulation of dead adults and unattractive spider webs spun around resting adults requires frequent cleaning of properties.
- Large numbers of dead midges can smell like rotting fish that persists in damp weather for several days after removal of adults.
- Midges have been documented to cause allergic reactions including conjunctivitis, dermatitis, rhinitis and asthma.