Cheap brand pasta are barely more expensive than that (0.7-1.2€/kg), so that sounds like that's the dominant factor at least for some brands.
Apparently in 2008 the price of wheat peaked at twice its current price (https://www.ifcm.co.uk/market-data/commodities-prices/wheat), but the price of pasta hasn’t halved since then.
Probably the imported durum wheat is used for other things, like farina or fodder.
I’m not saying that it will not happen a price increase, a lot of people are saying it also in Italy, but a lot less than the +50%, surely.
Here’s an interview with the CEO of an Italian pasta maker (La Molisiana):
"I know that Lidl has already increased the price of pasta by 10 cents - he adds - and I expect that well before Christmas everyone will expect increases between 15 and 20 cents per package".
Translate it: https://www.leggo.it/alimentazione/news/pasta_allarme_grano_...
durum wheat is "frumento duro".
The price now is 458,00 €/T which quite high.
https://www.ismeamercati.it/flex/cm/pages/ServeBLOB.php/L/IT...
The article shows that durum wheat prices have increased by more than 50%.
So assuming that the dominant factor in the price of pasta is the price of wheat, the price rise would be more like going from 2-3€/kg to 3-4.5€/kg