Julio Prieto, agronomist, oenologist and wine advisor states that in some wineyards, mildew disease has affected to 100% of farms.
Is there any relationship between the plentiful rains in the last months and pests?
Yes, there is a direct relationship. But we have to make the difference between pests and illnesses. When we refer to pests we mean insects and in this case the relationship to the increase in rains is not so close. However, illnesses caused by fungus and bacteria are boosted by humidity and temperature.
So, have illnesses increased this year?
Yes and it could be said that it is due to the pests’ resistance to humidity rather than to the rain. This year high temperatures in May have joined to the high rains, which has led us close to a tropical climate, in which likeliness of fungus to complete their cycles is really high. I have been working for 20 years in the Ebro Valle and had never seen such a thing.
Have wineyards been seriously affected?
This year’s wineyards have been seriously affected and Mildew has caused a lot of problems. The last register of this fungus attack dates back to 1982 and in 2020 it has attacked really hard, up to the extent of causing loss of 100% of farms. Here, the cierzo [wind blowing from Moncayo mountain] frees us from humidity and heat, but this year it hasn’t appeared and the fungus cycle was completed in five or six days, which meant it was impossible to stop once detected. If a producer started to implement prevention strategies after noticing the fungus it was impossible to stop its effects.
What other controls exist?
Fungus models can be created. All of them have models which predict what their evolution is going to be like and set the day they are appearing. The drawback of this model is that they are international and they usually fail because there is not a model of one’s own, for example, for Aragón. Every year we come across fake positive cases because our climate conditions are not the same as the ones in Europe, for example. This year we may have thought some positive cases to be fake owing to this reason.