Chile is reporting "serious damage" to a number of key fruit crops that are in their harvest season following unseasonal heavy rainfall of up to 60mm (2.4 inches) in production regions.

Fruit exporters' association Asoex said on Sunday evening that the rainfall - and hail in some cases - that hit the central and southern regions over the weekend has caused damage to summer fruit crops including blueberries, table grapes, and stone fruit.

The situation will result in lower export volumes than expected for the 2020-21 season, according to Asoex president Ronald Bown.

"We are living a very complex moment for the sector and the country," he said.

"At this time we have received new reports of splitting in blueberries from later areas, especially in the Brightwell and Ochlockonee varieties, while in the Last Call variety, the situation is under evaluation. However, the damage observed so far will affect the production and export volume of this 2020-2021 season."

The Chilean blueberry industry had last year forecasted a slight increase in fresh exports to around 111,000 metric tons (MT). According to the latest weekly crop, the country has so far sent 15 percent of its shipments for the season.

For table grapes, Bown said there are crops that have been "very damaged", not only due to splitting but also but to grapevine trellises collapsing due to the weight of the water.

"For example, in Rancagua, an important area in the production of this fruit, the Thompson variety is already showing evidence of "mal de media luna" (half-moon syndrome), associated with a fungus that rots the grain and damages any attempt to market the fruit," he said.

"In addition, hail fell in the area this morning, the effects of which are currently being evaluated."

As for stone fruit, there is loss of fruit due to splitting and possible rotting, Bown said.

He went on to say that the severe weather - which is uncommon in the middle of the summer season - adds to the pandemic-related problems the industry was already facing, such as the lack of labor and the problems in the Chinese cherry market.

"Although we know that the volume of production and exports will be affected, it is difficult to estimate the overall level of impact on the sector today, especially when it continues to rain in some areas, while others remain unaccessible. And there are effects, such as rotting, which will be seen in more detail as the days go by.

He said Asoex hopes to have more information this week.