(Decanter) - After the highs of 2013, Argentina is facing a much more complicated vintage this year, winemakers say.

Unhelpful weather at different times in the growing season, including frost and late season rain, means Argentina's 2014 wine grape haul is set to drop by around a fifth versus last year, according to the country's National Institute of Viticulture.

Some believe the drop could be even steeper. Lucila Pescarmona, who runs Lagarde winery in Lujan de Cuyo, Mendoza, with her sister, Sofia, told Decanter.com in an interview that production may fall by around 30% for 2014.

'2013 was the best vintage we have had in 40 years, but 2014 is going to be complicated,' she said, adding that producers are having to be more selective during harvesting.

Lagarde is beginning its Malbec harvest this week, having finished its white varieties, which include the up-and-coming Viognier grape.

But, Pescarmona believes that a smaller 2014 harvest could prove beneficial for many producers.

'There's a lot of grapes on the market. Exports came down a little bit last year and everybody has a lot of grapes to sell,' she said.

Speaking more generally about Argentina, Pescarmona said a key challenge for the country's producers is to communicate stylistic differences between Malbecs from different sub-regions - a point also made by Trapiche chief winemaker Daniel Pi late last year.

'Differences in terroir should not mean that one is better than the other,' said Pescarmona. 'We have to focus more on the typical style from an area. Chile has been doing this really well and Argentina needs to work harder, but it's not going to be easy.'

She added that, beyond Malbec, she is excited about the potential of Cabernet Franc in Argentina. Lagarde has produced a 100% Cabernet