The Irish Farmers Journal tested a number of different wildflower seed mixtures for blackgrass contamination.
This is because some wildflower seed mixtures were found to be contaminated with the highly invasive blackgrass weed in May of this year.
An experimental plot in Teagasc Oak Park planted with wildflower seeds for pollinators was found to contain blackgrass. The plot was immediately destroyed to prevent seed return and multiplication.
The discovery set off alarm bells for tillage farmers who at the time were seeing livestock farmers being encouraged to plant wildflower seeds on their farms as a biodiversity measure.
There are no herbicides available to fully control blackgrass in all situations, especially selective herbicides.
A single plant can spread over 6,000 seeds which can travel by wind, birds, animals, machinery or people.
Where it infests tillage land, it can leave that ground unworkable for years to come and grass crops can deteriorate in quality.
Germinal, from whom the seeds used in the experimental plot had been obtained, recalled its product and encouraged those who planted these seed mixtures to seek a visit from a representative of the company to inspect the area planted for the weed.
However, the only real control for this weed is a zero-tolerance approach. Where it is discovered in fields, crops or sections of crops are often sprayed off with glyphosate to prevent the return of viable seeds and to prevent further seed spread.
Many agri-retail outlets took all wildflower seeds off the shelves in response to the news, but seeds from many different sources and companies remained in many stores across the country.
More revelations emerged as time passed. It transpired that seed mixtures coming into the country were not certified and did not have to be declared free of blackgrass or any other weed seeds. As a result, the Irish Farmers Journal gathered a large number of samples of these seeds from different retail outlets across the country.
The seeds were then sent to the Department of Agriculture’s Seed Testing Laboratory in Backweston to be tested for the presence or absence of blackgrass.
The objective was to ascertain if blackgrass seeds were present in any of the wildflower products purchased.
Problems emerged with seed
A number of problems emerged when samples arrived at the lab. Out of a total of 29 samples, only 17 could be tested. Twelve could not be tested for the presence of blackgrass.
The main reason for not being able to test these was that the seeds were mixed with seed sowing granules. The contents of these granules were not specified on many of the products, but it was assumed to be a mixture of products like dried soil, compost and coconut shells.
Furthermore, some of these products come from across the water in Britain, which is now technically a third country from where soil is not allowed to be imported.
Another issue was that some of the products did not list the species that were to be present in mixtures, so there was no clear indication of what should be in the packets of seeds.
On a positive note, none of the 17 samples that went through the testing process in the lab were found to contain blackgrass.
This result should offer some comfort to wildflower seed producers, especially those producing indigenous species
It is worth noting at this point that all the samples collected and tested were mixtures of wildflower seed only, while the one that caused the problem last May at Oak Park was a mixture of wildflower and grass species.
This result should offer some comfort to wildflower seed producers, especially those producing indigenous species.
It also emphasises the great benefit in introducing a voluntary standard for their production, which has been implemented by the Irish Seed Trade Association, to set them apart from less certain imported mixtures.
Seed testing lab
The seed testing laboratory is part of the plant science division at the Department of Agriculture. It conducts tests for farmers and growers, seed merchants, and forest nurseries. Tests provided include germination and seed health, other seed determination in a sample and purity, among other things. It is a great asset and should be widely used by farmers of home-saved seeds.
What has/hasn’t happened since the discovery of blackgrass in wildflower seeds?