Отlayed sowing of winter rapeseed and conditions for infections and development of pathogens in late agricultural crops

After the prolonged drought, in early September economically significant precipitation of more than 30–40 l/m² fell in many parts of the country (Silistra, Varna, Dobrich, Stara Zagora, Burgas, Haskovo, Sandanski).

These precipitations were late even for the late field crops, which, as a result of the soil moisture deficit and above-normal summer temperatures, completed their development much earlier than the usual time limits.

During the current week as well, the agrometeorological conditions will be determined by unstable weather. Precipitation is forecast for the period, improving moisture reserves in the upper soil layers and the conditions for carrying out seasonal soil tillage.

Due to the drought, the pre-sowing tillage of the areas designated for sowing with winter rapeseed, a crop requiring precise soil preparation, was postponed. For this reason, in many parts of the country the sowing of rapeseed will be carried out after the optimal agrotechnical deadlines. They expire at the end of the second ten-day period of September.

On most days of the period, the forecast cool weather with frequent precipitation will create conditions for infections and development of pathogens in late agricultural crops: late brown rot on fruit trees, grey mould on grapes, downy mildew on vegetable crops.

During the second ten-day period of September, in cabbage grown for autumn production, pests should be monitored: the caterpillars of the cabbage white butterfly, the cabbage moth, the diamondback moth, and when their density exceeds the economic threshold of harmfulness (3–5 caterpillars per plant), treatment with insecticides with a short pre-harvest interval is necessary.

The upcoming period is suitable for sowing spinach and other leafy vegetables for autumn production.

Source: NIMH