(WHTM)– A helicopter will be flying across the Midstate on Thursday, spraying a liquid for black fly suppression.

The York County PA Office of Emergency Management announced that a low-flying helicopter will be spraying for black flies across the Midstate this week, per the PA Department of Environmental Protection.

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The Office of Emergency Management said the helicopter will be dispersing VectoBac 12AS, a Bti product manufactured by Valent Biosciences. The product is a bacterial larvicide used in Pennsylvania’s waterways to suppress flies, not a chemical.

The product is a “thick liquid that is brown in color when dispensed from the helicopter,” per the Office of Emergency Management.

The DEP said that the operation will begin at 7 a.m. on Thursday in Adams County. The helicopter is set to fly upriver and finish in Huntingdon County, spraying in Cumberland, Dauphin, Juniata, Mifflin, Perry, Lebanon, and York counties along the way.

The helicopter is a Bell OH58 A+ with the tail number N655HA and is white with red, blue, and grey striping, per the DEP.

The helicopter will fly low near the tree top level and release the liquid at predetermined positions in each stream, the Office of Emergency Management said.

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