The leaf:

There are still some myths of this plant being circulated and believed by some folks even though they have been shown to be simply a hoax. Firstly, the plant itself does not repel mosquito. Experiments conducted long time back had dispelled this myth [1, 2]. However, mincing its leaves and rub the liquid on the skin may actually prevent mosquito bites. But, it is not advisable to try it as your skin may be sensitive to the chemical compounds found in its leaves. Secondly, the plant is unlikely to be a genetic engineered species as claim, specifically a cross between an African geranium and a grass (Cymbopogon species).

The botanical name Pelargonium citrosum was used frequently but this may not be a valid name.

References:

[1] 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 mosquitos. J American Mosquito Control Association 1996;12(1):69-74. | Abstract |

[2] 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 American Mosquito Control Association 1994;10(4):473-476. | Abstract |