This year trick-or-treaters may be greeted with green-tinged pumpkins at their local supermarket after wet weather and slugs were blamed for what the industry called its ‘second-worst harvest on record’.

Supermarkets are warning shoppers that their pumpkins could be green-tinged to those looking to celebrate the spooky season.

Asda has been displaying signs that cautions customers, “Don’t worry if I’m slightly green, I will ripen at home and turn orange”, however the supermarket giant claims that despite their odd appearance, supplies will not be affected.

Asda said it had seen an increase in stock year-on-year, and expects to sell around 1.8m pumpkins nationally during the Hallowe’en season.

Despite this warning, other supermarkets are reassuring shoppers of the availability of the crop for Halloween, with Morrisons and Tesco reporting they have not experienced any issues.

It’s been a difficult year for pumpkin harvest, with farmers blaming the wet weather in spring and slugs for impacting the quality of the yield.

Speaking to The Guardian, pumpkin supplier Barfoots’ chief executive Julian Marks said some of the year’s initial plantings had “failed”.

Marks said: “When the weather improved the fields were replanted but some did not have enough time to turn orange. There is quite a lot of green out there.”

“In terms of ripeness, they’re perfectly good pumpkins and they’ll carve and look wonderful in the dark with a candle stuck in the middle, but they might not be 100% orange.”

British Growers Association chief executive Jack Ward added: “Pumpkins don’t like those conditions…slugs are a big problem too. It’s by no means universal. Some people have had a good run but I think the general feedback is that it has been a difficult season.”