A huge rise in the use of toxic pesticides on Scotland's famed strawberries, raspberries and other soft fruits has sparked health fears.

The latest survey for the Scottish Government reveals that the amount of pesticides applied per hectare by soft fruit growers centred in Angus leapt by 38% between 2010 and 2012.

Much of the increase was in fungicides to stop rot in wet weather, but there was also a 36% jump in the use of chlorpyrifos, which is an organophosphate insecticide that can damage the nervous system and kill wildlife.

The increases were described as "alarming" by the Scottish Wildlife Trust, while the Soil Association, which certifies organic food, warned of health risks. The pesticides industry, however, accused them of trying to "scare" people.

Over 1500 hectares were planted with strawberries, raspberries, blackcurrants, blackberries and other soft fruits in 2012, more than four-fifths of them in Angus. As much as 96% of the crop was treated with at least one pesticide, including fungicides, insecticides, herbicides and biological control agents.

The survey, by Science and Advice for Scottish Agriculture in Edinburgh, concluded that pesticides used rose from 17.5 to 19.6 tonnes between 2010 and 2012. When a 19% drop in the area grown was taken into account, it amounted to a per hectare increase of 38%. The use of chlorpyrifos rose from 652kg to 718kg, representing a per hectare rise of 36%.

In July, a mere two tablespoons of chlorpyrifos leaked into the River Kennet in Berkshire and wiped out all insect life in a 10-mile stretch. Anglers fear damage to fish could be irreversible.

According to Dr Maggie Keegan, head of policy at the Scottish Wildlife Trust, the rise in usage is worrying "because of the damaging knock-on effects these toxic chemicals can have on non-target species such as honeybees, bumblebees and other wildlife higher up the food chain".

She pointed out, however, that new EU laws would oblige farmers to reduce chemical usage on crops from next year. "That should prove a boost to wildlife in the countryside," she said.

Laura Stewart, director of Soil Association Scotland, warned that agricultural pesticides could damage the environment and leave toxic residues in food.

"Particular problems arise when more than one type of chemical is used in a so-called cocktail effect," she told the Sunday Herald. "Research on mixed chemical use, even at low levels, shows it can affect reproductive, immune and nervous systems."

But Nick von Westenholz, chief executive of the Crop Protection Association representing pesticide manufacturers, accused campaigners of trying to frighten consumers. "Pesticides are among the most heavily regulated products in the UK," he said. "Quite simply, fruit grown using pesticides is safe to eat. It's a shame the great benefits they provide to growers and consumers alike are undermined by simplistic objections."

The Scottish Government attributed the increased use of pesticides to 2012's record wet summer.

It was "mainly due to the increased use of fungicides to treat fungal diseases which thrive in wet conditions", said a spokeswoman.