Forest Pests: Insects, Diseases & Other Damage Agents

Mosquitoes Hazards of the Outdoors Written by Terry Price, Georgia Forestry Commission Adapted for the web by the Bugwood Network

Adult female mosquitoes are bloodsuckers and can be extremely obnoxious and potentially dangerous to humans. Immature stages of mosquitoes are aquatic, living in many habitats such as tree holes, marshes, swamps, rain puddles, ditches, discarded tires and other man made containers that trap water. Worldwide, mosquitoes transmit more diseases than other insects. Adult female mosquitoes vary in feeding habits. Some feed throughout the day while others feed at night and sporadically in the morning or afternoon. The day feeders are naturally the most obnoxious to foresters.

Figure 42 - Adult asian tiger mosquitoe Photo by Susan Ellis

In the southern U.S., mosquitoes are important vectors of the viruses causing encephalitis. These viruses occur naturally in wild bird populations and are transmitted to man and horses by female mosquitoes.

The eastern salt marsh mosquito Aedes sollictans is common in coastal areas and is a fierce biter. It migrates many miles from its breeding site and is known to transmit the eastern equine encephalitis virus. Breeding takes place in salt marshes flooded by tides or rain.

The southern house mosquito Culex quinquefasciatus is a major vector of the St. Louis equine encephalitis virus. This mosquito breeds in water in ditches, mudholes and storm sewers and water collected in tires, cans, and other items.

The Asian tiger mosquito Aedes albopictus until the 1980’s was found only in Asia and many islands in the Pacific Ocean, including some of the Hawaiian Islands. However, by 1986 it was discovered in Florida at a tire dump site in Duvall County. Now this mosquito is believed to be widely distributed throughout the southern and eastern U.S. (Figure 42). This mosquito transmits the virus causing dengue fever.

Filarial worms that infest animals and occasionally man are also transmitted by mosquitoes. The dog heartworm Dirofilaria immitis and the raccoon heartworm D. tenius are transmitted by mosquitoes and very rarely infest humans (Figure 43).

Figure 43 - Racoon filarial worm in human eye Photo by Richard R. Schulze

Prevention and Treatment of Bites

Forestry workers should wear protective clothing and a repellent to avoid mosquito bites. Repellents containing DEET (N,N-diethyl-M-toulamide) are very effective in repelling mosquitoes. Read all label precautions before applying repellents. Some of the bath oils and skin creams have gained fame in the last few years as being great mosquito repellents. Bites can be cleansed with soap and water. A topical antihistamine lotion will relieve itching temporarily. Bites should not be scratched to avoid secondary infections. If severe biting occurs watch for symptoms indicating fever or encephalitis.