The weather is worrying us, we are not ready for an attack of mildew

During the last weeks sudden weather changes have affected the vinegrowing of the Douro Valley. The last days of May were warm and not windy at all, which is perfect for pollination. We were really happy because we thought we would not need to spray our vines and therefore we could minimize the use of chemicals in our grapes. But between the 4th and the 6th of June it rained a lot, increasing the humidity, though with very low temperaturas (under 60º F or 16º C), which is cold enough to keep powdery mildew and oidium away from the vines. Between the 7th and the 9th of June the sun came back, temperatures increased to 80º F (or 27º C), which is quite dangerous due to the high level of humidity on the leaves and on the soil. But again from the 10th until the 14th of June it rained and the temperature went down. Today is hot again, temperature is well over 90º F (or 32º C), and we are worried about the weather. We did not spray the vines yet, we have just used sulfur powder to combat oidium. We are not protected against powdery mildew and some signs of worry are growing on my dad’s face…

Oscar

P.S. As suggested by one of our readers in Canada, we are also showing the temperatures in Celsius scale and not just in Fahrenheit scale. Thank you Steve for your suggestion!

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