Stop Dengue Now

  1. The National Environment Agency
  2. Dengue & Zika
  3. Stop Dengue Now
  4. Types of spatial repellents

Types of spatial repellents

1. Spatial repellents that have been shown to be effective


Types

How it works?

Mosquito coil


 

Mosquito-repelling chemicals are infused in coils. When the coil is ignited it produces a smoke that keep mosquitoes away.

Caution:

  • Use in well ventilated areas to reduce inhalation of smoke
  • Not recommended for people with respiratory problems
  • Potential fire hazard and should not be left unattended. Use with mosquito coil holder and keep away from combustible materials

Electric vaporisers

Chemical based electric vaporisers rely on heating element to volatilise and disperse mosquito-repelling chemical infused in mats or wicks.

Caution:

  • Chemical solvent may be flammable and should be used with caution
  • Mat/refill can only be used together with the heater from the same product

Chemical-based diffusers

Chemical based emanators contain mosquito-repelling chemical that is infused into paper, plastics, or agarose gels, and readily vaporises under ambient condition.

2. Spatial repellents that have been shown to have limited effectiveness 


Types

How it works?

Plant based candles

Plant based extracts with repellent properties are incorporated into candles or used directly in diffusers to produce vapour and repels mosquitoes. However, there is limited data on the efficacy of candles and diffuser in repelling mosquitoes even when these materials are infused with plant extracts that are known to repel mosquitoes.

Caution:

  • Use in well ventilated areas to reduce inhalation of smoke
  • Not recommended for people with respiratory problems
  • Potential fire hazard and should not be left unattended

3. Spatial repellents that have been shown to be ineffective


Types

How it works?

Ultrasonic devices

Studies have shown that ultrasonic devices are ineffective in preventing mosquitoes bites although these products claim to produce soundwaves that interfere with mosquitoes’ sensory systems.

Plants

Examples of such plants are Geranium (Pelargonium graveolens), Lemon balm, Rosemary, Citronella, Lavender, Lemongrass, and Peppermint.

Although some plant extracts have insect-repelling properties, studies have shown that the use of plants are not effective at repelling mosquitoes. The repellent compounds are only released when the leaves are crushed or burnt.

Plant-based compounds with repellent properties may be infused into paper, plastics, or agarose gels. Examples of emanators include mosquito repellent patches, wristbands and gel based emanators.

However, studies have shown that these products are not effective in repelling mosquitoes.

Further readings:

1. Cilek JE, Schreiber ET. Failure of the "mosquito plant", Pelargonium x citrosum 'van Leenii', to repel adult Aedes albopictus and Culex quinquefasciatus in Florida. J Am Mosq Control Assoc. 1994 Dec;10(4):473-6. PMID: 7707049. 
2. Foster WA, Lutes KI. Tests of ultrasonic emissions on mosquito attraction to hosts in a flight chamber. J Am Mosq Control Assoc. 1985 Jun;1(2):199-202. PMID: 2906666.
3. IVCC. Innovative Vector Control Consortium. An expert review of spatial repellents for mosquito control. 2020.
4. Liu W, Zhang J, Hashim JH, Jalaludin J, Hashim Z, Goldstein BD. Mosquito coil emissions and health implications. Environ Health Perspect. 2003 Sep;111(12):1454-60. doi: 10.1289/ehp.6286. PMID: 12948883; PMCID: PMC1241646.
5. Maia MF, Moore SJ. Plant-based insect repellents: a review of their efficacy, development and testing. Malar J. 2011 Mar 15;10 Suppl 1(Suppl 1):S11. doi: 10.1186/1475-2875-10-S1-S11. PMID: 21411012; PMCID: PMC3059459.
6. Mapossa AB, Sitoe A, Focke WW, Izadi H, du Toit EL, Androsch R, Sungkapreecha C, van der Merwe EM. Mosquito repellent thermal stability, permeability and air volatility. Pest Manag Sci. 2020 Mar;76(3):1112-1120. doi: 10.1002/ps.5623. Epub 2019 Nov 8. PMID: 31576645.
7. Matsuda BM, Surgeoner GA, Heal JD, Tucker AO, Maciarello MJ. Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitoes. J Am Mosq Control Assoc. 1996 Mar;12(1):69-74. PMID: 8723261.
8. Rodriguez SD, Chung H-N, Gonzales KK, Vulcan J, Li Y, Amumada JA, Romero HM, Torre MDL, Shu F, and Hansen IA. Efficacy of some wearable devices compared with spray-on insect repellents for the yellow fever mosquito, Aedes aegypti (L) (Diptera: Culicidae). J Insect Science. 2017 17(1): 24: 1-6
9. Sylla el-H K, Lell B, Kremsner PG. A blinded, controlled trial of an ultrasound device as mosquito repellent. Wien Klin Wochenschr. 2000 May 19;112(10):448-50. PMID: 10890136.