In the first ten days of May, there will be an improvement in soil moisture reserves and a risk of downy mildew in vineyards

After the dry and unseasonably hot weather at the end of April and the beginning of May, during the next seven-day period the agrometeorological conditions will undergo a significant change.

By the end of the first ten-day period, a decrease in temperatures and a normalization of thermal conditions are forecast. The expected widespread precipitation will improve soil moisture reserves in the upper layers and the conditions for the progress of the initial stages of vegetation of the sown sunflower and maize crops. This precipitation will have a beneficial effect on wheat, barley and winter rapeseed, which are undergoing moisture-critical phases. In wheat and barley, the heading stage will be observed on a mass scale. In the earliest heading crops, during the third ten-day period of April (agrometeorological stations: Knezha, Pavlikeni, Tsarev Brod, Pazardzhik, Plovdiv, Yambol), flowering, fertilization and grain formation will take place. In winter rapeseed, pod formation will occur.

During the period, the stage of inflorescence separation will occur in the vine. Frequent precipitation and lower temperatures at the end of the first ten-day period will increase the risk of infection and development of downy mildew in the vine, which requires preventive treatment after weather stabilization. Upon the appearance of the first symptoms of downy mildew, the use of systemic fungicides is imperative. An increased likelihood of hail is forecast for the period. In case of hail damage, the affected fruit crops should be treated at the first opportunity with copper-containing fungicides in order to accelerate wound corking and limit the risk of secondary infections by pathogens.

Source: NIMH