The Met Éireann blight season will begin tomorrow (Wednesday, May 1), after continued rain has left some fields in unworkable conditions.
Potato blight is caused by a fungal-like organism called Phytophthora infestans.
The pathogen thrives in humid weather spreading rapidly on the foliage of potatoes and tomatoes, causing the leaves to decay and the crop to become infected.
Continued wet conditions need to be combined with temperatures above 10° consistently in order for blight to develop, according to Met Éireann agricultural meteorologist Padraig Flattery.
Met Éireann produces a three-day, four-day and five-day forecast spatial maps for the island of Ireland, which illustrates the blight risk at five different risk levels from very low (green) to very high (red).
There is still no means of eradicating an outbreak of blight in a potato crop, meaning that prevention is key.
The need to both mix and alternate fungicide chemistries was highlighted at the recent Teagasc Potato Late Blight Workshop.
Planting blighted tubers is also a potential source of the disease. Therefore make every effort to ensure that all tubers are picked at harvest time and that volunteer potato plants are not allowed to grow the following year.
Met Éireann
Rainfall levels this week have been variable, with drier than average to average rainfall across much of the country.
This is excluding parts of the west, midlands and southeast where above average rainfall was recorded.
It is expected to be wetter than normal across much of the country during the next seven days, as low pressure remains positioned near Ireland pushing in bands of rain and showers.
Rainfall totals are generally expected to range from 20-40mm.
In the week ahead, it will remain cooler than average for the time of year, ranging from 9° to 11°.
Soil temperatures will remain above average, between 10° in the southeast and 11.9° in the west.
Field conditions
Currently all well drained soils and most moderately drained soils have good trafficability of light and medium soils, according to Met Éireann.
Soil moisture deficits vary for poorly drained soils from -10 to +10mm, with the best of the deficits in parts of the east and south midlands.
With increased rainfall in the coming seven days, soil conditions will deteriorate slightly, particularly early in the week with a gradual improvement again towards the weekend.
Though soil moisture deficits will decrease, most well drained and poorly drained soils will remain trafficable. However, poorly trained soils will become saturated or waterlogged.