(ANSA) - Rome, August 14 - The arrival of a new heat wave over the next few hours is expected to bring the cost up to one billion euros in agriculture damage as Italy's worst drought in 10 years continues to wreak havoc, farming association Colidiretti said Tuesday. National production of tomatoes has dropped 20% amid the dry spell while that of corn has plummeted 30%, it said. Soya production so far this year has contracted 40%. Coldiretti said it also expects reductions of almost 50% in the production of beetroot, used to produce white sugar, and a 20% decline in sunflowers. The upcoming grape harvest is expected to suffer the steepest decline in volume in a century, though quality will be high, according to the report. "We are facing climatic changes and need to intervene with financial assistance that will permit us to face the emergency, also with structural measures," Coldiretti President Sergio Marini said in the statement.