The aerial spraying of area salt marshes — with an eye on controlling mosquito larvae — which was announced Wednesday for Thursday and Friday has been extended to include Saturday, Suffolk County health officials said.

Marshes in areas of the towns of Riverhead and Southold have been added to the previously announced list of Babylon, Islip, Brookhaven, Southampton and East Hampton.

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The pesticides VectoBac 12AS Liquid Concentrate and Altosid Liquid Larvicide Concentrate are to be used, weather permitting, between the hours of 5 a.m. and 8 p.m.

Precautions are not necessary, health officials said, as “the helicopter will be flying at a very low level over marsh areas and taking other precautions to control airborne drift into inhabited areas.” Also, the pesticides that are being used “have no significant human toxicity,” they said.

Besides being annoying, some mosquitoes’ bites can transmit West Nile virus to humans.

For more information, visit http://suffolkcountyny.gov/Departments/HealthServices/tabid/132/ctl/details/itemid/5564/mid/907/aerial-spraying-for-mosquitoes.aspx.