Blackgrass is now likely to be present in most counties in Ireland, according to the Department of Agriculture, Food and the Marine (DAFM).
The invasive weed is seen as a key challenge for Irish tillage farmers as it can “lead to significant loss of yield in cultivated crops”.
Farmers have been urged by the department and Teagasc to be vigilant and take a zero-tolerance approach to the plant.
Blackgrass
Incidences of blackgrass were reported by the Botanical Society of Britain and Ireland dating back to the 1950s. The plant is widespread and very problematic in the UK.
“It should be noted that there is no legal obligation to report instances of blackgrass. However, blackgrass is likely to be present in most counties, especially those with a significant proportion of arable crops,” a DAFM spokesperson outlined.
The “vigorous and competitive weed” produces up to 6,000 seeds/plant, which can be easily spread through seed; soil; machinery; and straw.
In 2021, Teagasc discovered blackgrass in a commercial wildflower mixture growing in an experimental plot at its Oak Park facility in Co. Carlow.
It led the national farm advisory body to issue a warning to the public to check wildflower plots grown with imported seed mixtures for the weed, which has “a narrow dark purple to black seed head”.
Prevention better than cure
Once established, blackgrass is particularly hard to control due to its resistance to some of the main herbicides on the market.
“While herbicides give some control, the level of resistance has been increasing. As a result, the most effective control is through cultural control in crop rotations and through the prevention of transfer both within farms and between farms,” DAFM stated.
“The most effective control is to prevent the introduction and establishment of the weed at farm level.
“This is best achieved through the use of Irish certified seed where there is zero tolerance of blackgrass in the seed crop and in the certified seed,” the department spokesperson added.
When it comes to agricultural equipment, whether it is owned or contracted, DAFM advises that it should be “thoroughly cleaned” before use and movement both within farms and when moving between holdings.
“Agricultural contractors need to take particular care to ensure their equipment is thoroughly cleaned before moving from one farm to another and indeed should be mindful of internal movements within fields on a farm.
“Where blackgrass is detected the farmer should contact their agronomist or agricultural advisor on how best to deal with the plant on their farm,” DAFM outlined.
Seed
In order to help control the spread of the invasive weed, the department has a voluntary agreement with the Irish Seed Trade Association to impose “zero tolerance” for blackgrass in seed that is certified in Ireland.
Under EU legislation, any seed for cultivation imported from a third country outside of the European Union requires a phytosanitary certificate.
However, straw is not a regulated plant under EU legislation and does not have phytosanitary requirements.
Imported farm machinery from third countries must be accompanied by such a certificate confirming it to be clean and free of soil or plant debris of any kind.