Erin Patterson trial: Fungi expert Tom May says public has ‘poor’ ability to identity mushrooms

Erin Patterson’s triple-murder trial has been told about three other mushroom poisonings in recent years in Victoria.

Details of an elderly Victorian woman’s death due to death cap mushroom poisoning has been aired during Erin Patterson’s triple-murder trial.

Mycologist Tom May returned to the witness box on Wednesday for Ms Patterson’s trial over the allegedly deliberate poisonings of four of her in-laws on July 29, 2023.

Under cross-examination by Ms Patterson’s barrister, Sophie Stafford, Dr Stafford was questioned on other known mushroom poisonings in recent years.

He agreed in May 2023, a Chinese tourist was admitted to hospital with signs of organ failure after consuming a young mushroom he’d foraged about 50m from an oak tree. 

The tourist spent a week in hospital but was released fully recovered, Dr May said.

The following year, a elderly woman and her son were poisoned after she picked mushrooms growing in her garden on May 15 and prepared a dish, the jury was told.

Both were hospitalised with the elderly woman dying while her son survived, Ms Stafford said.

Dr May agreed he was aware of the case and a coronial report after being contacted by the Department of Health to assist in preparing a campaign warning about the dangers of consuming wild mushrooms.

Dr Tom was recalled to give evidence on Wednesday. Picture: NewsWire/ David Crosling

Public has ‘poor’ ability to correctly identify mushroom: Dr May
Dr May was quizzed on mushroom foragers’ ability to correctly identify wild mushrooms.

He agreed, based on his interactions over decades as an expert, the general public had a “poor ability to accurately identify wild mushrooms”.

Dr May told the jury that he believed mushroom foragers should undertake a years-long apprenticeship to accurately identify mushrooms.

Dr May told the court, in his experience, fresh death cap mushrooms have no particular smell but were “quite sweet”.

“I have dried them on a number of occasions and have found the smell to be unpleasant,” he said.

Death Cap mushrooms can be visually similar to other mushrooms: expert

Ms Stafford took Dr May through a series of images of mushrooms taken from citizen science website iNaturalist, quizzing the mycologist on whether they were toxic to humans and visual similarities to death cap mushrooms.

These included the Buttery Collybia, species from the genus commonly known as Honey Mushrooms, the Shaggy Parasol, the Spotted Stem Ringless Amanita and the Spring Field Cap.

Dr May confirmed several of these were known to cause gastrointestinal symptoms while others are not, and each shared some visual similarities to the death cap.

This included a white to green, yellow or brownish coloured cap, whitish stem, white gills, ring and cup.

Most of the species, he confirmed, were believed to grow in Victoria.

Dr May agreed the death cap mushroom can be visually similar to other known mushroom species.

He told the jury he believed he has identified more than 30,000 photos of mushrooms on iNaturalist, but generally will not post an identification without seeing the underside of the mushroom.

Dr May spent decades as a principal research scientist at the Royal Botanic Gardens in Melbourne. Picture: NewsWire/ David Crosling

Toxic mushrooms difficult to identify: expert

There’s been a “significant” rise in calls to the Victorian poisons centre about mushroom exposures in recent years, the jury was told on Tuesday.

Ms Stafford questioned Dr May on an academic journal article he co-authored in 2023.

The jury was told the study used available mobile and web apps to identify photographs of mushrooms that had been sent to the Victorian Poisons Information Centre – concluding there was a “poor” accuracy in correctly identifying poisonous mushrooms.

“We showed that those apps sometimes failed to correctly identify mushrooms,” Dr May said.

“Sometimes they were misidentified as the wrong mushroom.”

Erin Patterson is facing trial after pleading not guilty. Picture: NewsWire/ David Crosling

Dr May told the jury the primary motivation for the study was the increasing availability of the apps, but agreed with Ms Stafford that there seemed to be an increase in people foraging for wild mushrooms in recent years.

“And accordingly, poison centre calls regarding mushroom exposures in the state of Victoria have increased significantly in recent years?” Ms Stafford asked.

Dr May responded: “That appears to be the case.”

“There certainly was an increase in the calls during the Covid period, but it was also a rather wet year, so it was actually hard to disentangle these different factors,” he said.

Don and Gail Patterson died within a day of each other. Picture: Supplied

Korumburra pastor Ian Wilkinson survived while his wife Heather Wilkinson also died following the lunch. Picture: Supplied

Her husband’s parents Don and Gail Patterson, both 70, and Gail’s sister Heather Wilkinson, 66, died after consuming death cap mushrooms inside a beef wellington that Ms Patterson served.

Ms Wilkinson’s husband Ian Wilkinson, 71, survived after a long stint in hospital.

Ms Patterson has pleaded not guilty to three counts of murder and one count of attempted murder relating to the fatal lunch.

At the start of the trial her barrister, Colin Mandy SC, told the jury Ms Patterson did not intentionally nor deliberately poison anyone, labelling the deaths a tragic accident.

The trial continues.

Originally published as Erin Patterson trial: Fungi expert Tom May says public has ‘poor’ ability to identity mushrooms