The Regency Purchasing Group said supply issues created by this summer’s heatwave may mean buyers struggle to purchase certain produce, including some of the chief elements of pub staples.
The industry’s difficulties will result in increased prices, according to the group, which works with more than 2,700 leisure businesses throughout the UK.
Some crops have wilted and farmers have been forced to feed livestock winter food already, as the usual grazing grass has not regrown due to a lack of rain.
Regency managing director Alex Demetriou said: "Harvests are generally lower, and while some producers have irrigation systems to help combat the heat, the costs of using them is becoming more expensive.
"Those who do not have irrigation systems are seeing yields as low as 60% of their usual output, which again means prices will inevitably rise, so anything that the Government can do to ease the pressure on producers would be very welcome."
Vegetables including asparagus, cauliflower, broccoli, salad crops and maize crops have been negatively affected.
As lettuce will not grow in temperatures above 27°C, supply has not been able to match its soaring demand caused by the prolonged heatwave.
It is possible to import some produce from the continent to make up for a shortfall, but with most of Europe experiencing the same high temperatures, this has not been possible with lettuce.
There are also fears the potato crop may be impacted, though it has not yet materialised. If there is a weak potato yield, the market may respond with a shortage or with more imports from Europe.
The UK is usually dependent on its seasonal products to help reduce prices of other favourite produce but this will not be the case if imports are needed.
A shortage of seasonal workers caused by Brexit has also been blamed for difficulties in the industry this summer.
Demetriou said the sector was reliant on seasonal migrant workers, mostly from eastern Europe, to harvest crops.
He said: "The primary reason we are now losing European workers is that the exchange rate has never recovered from the Brexit vote.
"To have crops dying in the fields, as a result of the exchange rate, is a shameful situation that needs to be addressed, particularly in light of the recent prolonged hot spell, which could also adversely affect the availability of produce."
Demetriou urged the Government to introduce a seasonal worker visa scheme.
He added: "If they take no action, and the shortage of seasonal workers continues, there will be a pitiful waste of fruit and vegetables, harvests for which have already been hit by the heatwave.
"The net result of this will be even higher prices in the shops, which will have an impact on everyone."