By Michael Keaveny
It is important to utilise as many control measures as possible as part of an integrated pest management system (IPM) for effective disease control in tillage crops.
Over-reliance on any one tool will be ineffective and unsustainable.
One of the key elements in any IPM system is fungicides. These allow for a more intensive production system, enabling higher output from a smaller area due to greater disease control.
For example, Europe accounts for 11pc of the world cereal production from only 6pc of the world's cereal acreage, indicating highly intensive cultivation. Similarly, Europe accounts for about 80pc of the worldwide cereal fungicide market.
Until the mid-1960s, fungicide use on wheat in Europe was unusual, says Ashley Williams of croplife.org. However, during the '60s there was increasing evidence that diseases of wheat were causing more losses than had previously been acknowledged. At the end of the decade, the first foliar fungicides targeted specifically at cereal diseases were introduced.
Midway through the '70s, new fungicides were developed to significantly broaden the number of diseases treated.
By '79 about 25pc of the cereal hectares in Western Europe - and 50pc in the UK - received at least one foliar fungicide treatment.
Since the '90s, more than 95pc of wheat acres in the UK, France, Germany, Denmark, Belgium and the Netherlands have been treated with fungicides.
Fungicide use has been a major factor in rising European wheat yields since the '70s.
However, while fungicides are a key component in the production of high-quality tillage crops, their availability to Irish farmers is being reduced every year due to increased EU regulation.
For example, the EU decided last year to ban Chlorothalonil, a highly effective multi-site fungicide that has been used for over 50 years.
The ban takes effect next month, and a withdrawal period for the product is due to end here on May 20.
The EU cited "scientific evidence and research which points to concerns around the chemical's impact on aquatic life and human health" for banning the product.
Teagasc crop expert Shay Phelan says that while new products are being introduced, the Chlorothalonil ban may lead to increased resistance to active ingredients in other fungicides.
"Two new products have been introduced on the back of Chlorothalonil being banned - Revysol and Inatreq have both been approved recently," says Phelan. "However, Chlorothalonil is not alone a fungicide in its own right, it also helps protect the other fungicides that it is used alongside.
"We have to be aware that fungicides have a finite lifespan so the more times they are used, the less of an impact they have.
"So through using Chlorothalonil, farmers were using less of other fungicides, which meant there was less chance to build up resistance to them; so without it, the other active ingredients will come under pressure quicker."
"In Ireland, most cereal products are being used for animal feeds, so the risk to consumer health is small. Chlorothalonil is being banned mainly due to user-health concerns, despite farmers being well trained in wearing adequate PPE gear," Phelan said.
Teagasc research has found that the ban, which is due to come in next month, will see tillage farmers' average net margins reduced by over 50pc in wheat and 65pc in barley for growers achieving national average yields.
Cereal production will only be economically viable on the highest-yielding sites with low costs of production as the risks of financial loss will increase dramatically on other sites.
Teagasc also said that Irish growers will lose competitiveness as it is anticipated that other regions will not suffer the same losses, and consequently grain prices will not rise in Ireland to offset yield losses.
Ireland also has a greater need for fungicides due to our wetter climate, says Shay Phelan.
"Ireland has more fungi due to our damp weather compared to some of our drier European counterparts. The EU, unfortunately, can't give derogations to some member nations, based on climate, because it could open a can of worms on a whole host of other issues."
Consumer lobby groups also have massive influence when it comes to banning products, which Phelan says can have a big influence on policy-making.
"It is very hard to disprove something. As a result, certain decisions are made on science but others are made on sentiment."