During the first half of May, there will be favorable conditions for the development of the infectious background of a number of fungal diseases in agricultural crops

Frequent, locally intensive, precipitation at the beginning of May will be a precondition for an increase in the infection pressure from a number of fungal diseases: fusariosis and rusts (yellow, brown) in wheat and barley; downy mildews in vegetable crops; scab and shot-hole disease in fruit trees; downy mildew and powdery mildew in grapevine.

During the first ten-day period of May, agrometeorological conditions will be determined by unstable weather with frequent showers, which in many parts of the country will hinder the implementation of seasonal agrotechnical activities – completion of sowing of grain maize, pre-sowing tillage and sowing of late thermophilic spring crops – beans, cotton, peanuts, watermelons, melons, etc.

During this period, the development of the autumn-sown stands and the sown spring crops will take place at mean daily temperatures close to the climatic norms and in the presence of good soil moisture reserves in the 50 cm layer, above 85% of field capacity (FC). During the ten-day period, in wheat and barley in the field regions of the country, the heading stage will be observed on a mass scale, and in some places in Southern Bulgaria – the beginning of flowering.

At the end of the first and the beginning of the second ten-day period, an increase in temperatures and an acceleration of vegetation in agricultural crops are forecast. By mid-May, flowering and fertilization will take place in winter cereal crops, and in maize and sunflower – leaf formation. In early spring crops (vetch, peas) budding and flowering will be observed.

In fruit crops not affected by the April frosts, the formation and enlargement of fruit set will take place. In grapevine, inflorescence emergence will be observed.

Frequent, locally intensive, precipitation at the beginning of May will be a precondition for an increase in the infection pressure from a number of fungal diseases: fusariosis and rusts (yellow, brown) in wheat and barley; downy mildews in vegetable crops; scab and shot-hole disease in fruit trees; downy mildew and powdery mildew in grapevine. More suitable conditions for conducting plant protection sprayings will occur at the end of the first and in the first half of the second ten-day period.

By mid-May, no critical minimum temperatures for agricultural crops are forecast. During the first ten-day period, an increased probability of hail is expected. In case of hail damage, it is advisable that the affected crops be treated at the first opportunity with copper-containing fungicides for faster healing of wounds and for reducing the risk of secondary infections.

Source: NIMH-BAS