There are now cases of late blight in all three counties of P.E.I., a week after the first reports of the fungus on the potato crop.

Late blight shows up as black spots on potato leaves and destroys the potato under the ground. The potentially devastating pest has arrived a few weeks earlier than normal this year.

Late blight appears as black spots on the leaves, and destroys the potato under the ground
Late blight appears as black spots on the leaves, and destroys the potato under the ground

"We've had some cases in the east. Things started off there, moved towards central and then there were three cases confirmed in the West Prince area in the last couple of days," Rachel Cheverie of the provincial Agriculture Department told CBC News Thursday.

"You can't really compare year to year because it's so dependent on weather conditions. You know some years are good blight years, other years are bad blight years. Weather conditions this year have definitely been conducive to blight."

She says there are now a dozen confirmed cases. The department is encouraging anyone who suspects they have blight in their field to contact them.

Without treatment late blight is capable of destroying entire potato crops.

Farmers in the province have stepped up their spraying of fungicide, spraying every five to seven days.