Karri Country Produce owner Jennie Franceschi, who wholesales WA avocados, said between 30,000 and 80,000 trees had been planted annually in the South West over the past six years.

 Avocado trees take five years to deliver their first fruit, so even bigger volumes will hit the market in coming years.

Manjimup avocado and apple farmer Vic Grozotis said though climatic events might cause shortage-driven price spikes, overall the long-term trend was spiralling downwards because of the huge increase in future production.

Avocados Australia said WA 10 years ago produced 3000 tonnes of avocado, growing to 20,000 in 2017 and expected to reach 30,000 within five years. Australia wide, 77,000 tonnes was produced last year, expected to grow to 115,000 tonnes by 2025.

Mr Grozotis, who also runs a commercial packing shed, estimates his own operation is handling between 15 and 20 per cent more avocados than a year ago.

He said despite lower prices this year, growers were still achieving a reasonable return.

“Avocados are now more affordable for the consumers and now represent good value for a quality WA product, while the price paid to the farmer is also reasonable,” he said. “We’ve reached a good pricing point for a sustainable industry, but need to maintain that balance.”

Future bigger volumes mean developing export markets is vital to soak up the rapidly growing supply. WA already exports a small volume to Singapore, Malaysia and Hong Kong.

Avocados Australia chief executive John Tyas said the first consignment of WA avocados to Japan would occur within weeks, after years of negotiations to open up the market.

Other potentially important export markets include Thailand and China.

“Australians eat on average 3.5kg of avocados a year,” Mr Tyas said. “Only 70 per cent of Australian households eat avocados, indicating room for further growth.”

Mr Grozotis said though Australia competed with New Zealand avocados on the domestic market, the Australian product attracted better prices because they were a higher quality product.

He said local growers faced other challenges. In the past year, a pest called the six spotted mite had taken a grip in the South West.

The mite does not affect fruit directly but defoliates the trees, leaving the fruit exposed to sunburn and forcing growers to harvest their fruit earlier.

“Because there has been intensive plantings in the area, the mite has spread rapidly, and growers are quite concerned,” Mr Grozotis said.