Agrometeorological forecast for April – favorable conditions for the development of fungal diseases in fruit trees

During the first ten-day period of April, agrometeorological conditions will be determined by unstable weather with frequent precipitation, which will improve soil moisture reserves and the conditions for the development of winter crops and the sown spring crops. The precipitation that fell in the last days of March increased the moisture reserves in the upper soil layer. At the beginning of the spring vegetation period, as a result of the snowless winter and below-normal precipitation in February, soil moisture reserves in the 50 cm and 100 cm layers in winter cereals were unsatisfactory for the season, especially in some of the eastern and southern regions, where the level of moisture reserves was below 65% of FC (Field Capacity).

During the first half of April, the development of agricultural crops will proceed at a moderate rate, at temperatures close to the climatic norms. In the middle of the first ten-day period, a short-term, substantial decrease in temperatures is forecast, with minimum negative values down to minus 2-3°C, which, if they persist for a longer time, will be critical for the blossoms and young fruit set of fruit trees. During the first ten-day period, wheat will be in the stages of tillering, transition to stem elongation, and stem elongation in the crops in the Danube Plain and in the southern regions. 

A substantial improvement in thermal conditions and an acceleration of vegetation in agricultural crops is forecast for the second half of April.

The expected precipitation at the end of the second and the beginning of the third ten-day period will maintain good levels of moisture reserves in the 50 cm layer – of major importance for wheat and barley, in which the mass stem elongation stage and the transition to heading will occur – stages during which the water requirements of winter cereal crops from soil moisture increase sharply. At the end of April, in some of the earliest stem-elongated crops in the Danube Plain, the heading stage will be observed (agrometeorological station Novachene, Silistra). During the interstage period stem elongation – heading, wheat crops must be regularly monitored for the appearance and harmful activity of certain pests: the cereal leaf beetle, wheat thrips, sunn pest, and, when pest density exceeds the economic threshold of harmfulness, timely treatment must be carried out.

In the field regions, at the beginning of the third ten-day period, soil temperature in the 10 cm layer will reach suitable values for sowing maize for grain, and by the end of the month – also for thermophilic spring crops (cotton, beans, peanuts, watermelons, melons, etc.).

Frequent precipitation in April will create favorable conditions for the development of fungal diseases in fruit trees (blossom blight, shot-hole disease, scab, etc.). More suitable conditions for carrying out plant protection spraying will occur in the middle of the second and during most days of the third ten-day period of April.

Source: NIMH