At last week’s ITLUS conference, it was obvious that the toolbox available to tillage farmers is becoming increasingly bare. Chemical control agents are not being replaced by better products and we are losing many older actives.

The biological products being favoured to replace them are still not sufficiently fine-tuned to be useful in field crops. And many new and potentially useful plant breeding technologies are being denied to the sector in Europe.

This points to the fact that good farming and increased use of integrated pest management (IPM) will be essential for the future.

The chemical actives

Records show that chemicals have been with us since as far back as 2000BC. And products like The Bordeaux Mixture and mercury originated in the late 1800s.

But it was really since the 1950s that the majority of chemical actives arrived. This continued up to the turn of the century, but it has slowed considerably since then, especially in Europe.

This is partly to do with ever-increasing development costs for new products, plus the increasing uncertainty of continued market access in the EU.

The high development cost, estimated either side of $300m per active, is one of the factors that continues to drive rationalisation. Very many of the names of three decades ago are now gone and rationalisation continues.

At the ITLUS conference, Gordon Rennick from the Pesticide Registration and Control Division in the Department reminded us of the very many actives that have already gone from the market. These include names such as Punch C, Metasystox 55, Commando, MBCs, Lindane, Gramoxone, simazine, atrazine, ioxynil, Guazatine and most recently, isoproturon (IPU), Lexus and Maneb.

There were about 1,100 actives registered for use in the EU 25 years ago. Today, this number is little more than 400 and only about 300 of these are useful for field crops.

Gordon said that new actives tend to be more targeted but the rate of discovery is much lower. As a consequence, new actives tend to be more biologically active and show improved safety.

In 1945 a full rate of MCPA applied 1,650g/ha of active; in 1983 a full rate of metsulfuron-methyl applied only 6g/ha.

The introduction of hazard-based evaluation in EU pesticide regulations changed a lot of the rules. The impact of cut-off criteria and comparative assessment will continue to bring changes.

Actives such as mancozeb, prothioconazole, silthiofam, 2,4-D, diflufenican, ethofumesate, lambda-cyhalothrin, esfenvalerate, flufenacet, prochloraz, tebuconazole, metconazole, propiconazole, metribuzin and dimethoate are among those that could be lost in the future.

In modern society, arguably the biggest threat is coming through social media, where information gets distorted to meet individual objectives.

Biological control agents

There will be more emphasis on biological control methods in the future, but many are still not suitable for use on broadacre crops, according to Michael Gaffney of Teagasc. That said, up to 50% of the pest control tools are expected to be biological in the EU by 2020.

Biological actives are useful in protected crops, Michael said, and about 70% of the value of such products use using either predators or parasites on indoor crops.

Michael believes that biological products may have potential for field crops in the future. Many current products were developed to fill gaps in the horticultural sector when actives were lost.

Part of their success involved learning more about individual pests. Efficacy continues to be enhanced by improved knowledge of both pest and predator.

Biological products cost three to four times more than conventional chemistry, but they are cheaper to develop (possibly 150 times cheaper).

Processing techniques for the control agent continue to improve efficacy. Control agents use insects, nematodes, fungi and even plant extracts known to modify insect behaviour. Most of the current tools are for pest control.

However, there are also concerns about the prospect of releasing control agents that could self-propagate in nature.

We must remember that what is natural is not always wonderful. Michael referenced the example of the harlequin ladybird as a potential beneficial that went rogue.

Concluding, Michael said that crises help create opportunities for these products. While the science is still in its commercial infancy, more products are being made available and some will, in time, be useful for biological control in field crops.

Plant breeding technologies

If chemical tools are in short supply and biological techniques are mainly useful for pest control, how will Irish growers contain plant diseases? One of the main possibilities to do this would be through the fine-tuning of plant genetics.

Dr Tom McLoughlin, formerly responsible for GMO legislation at the EPA, told the meeting that there are very many good and precise new technologies available which can help plant breeders. The challenge is that these are virtually all legislated for under the umbrella of GMO legislation in the EU.

One of the now older modern technologies involved the transfer of genes from one species to another to confer a specific characteristic. This was used to confer insect resistance and herbicide tolerance to a range of crops that is referred to as GM or GMO (genetically modified organism).

These techniques are now widely used in the production of medicines like insulin and many others, but they remain unacceptable in farming in the EU.

Tom defined a GMO as an organism/micro-organism in which the genetic material has been altered in a way that does not occur naturally by mating or natural recombination.

Transgenic plants first appeared in 1994 and very many new technological tools have been developed since then. In true GMOs, the insertion of DNA brings about a change in the protein make-up and this can be detected.

Many of the new tools do not result in a change in natural protein and so they are not technically detectable. Together, these tools are now referred to as new breeding techniques (NBT).

Some of these tools might also be referred to as gene editing. Effectively, NBTs enable plant breeders to develop new plant varieties faster and with more precision than in conventional breeding.

They also allow for the switching on or off of individual genes to enable greater or lesser expression of a particular characteristic.

In the EU, legislation controls the processes which make these changes, while in other regions, such as the US and Canada, legislation governs the end product. EU legislation also governs all other biotech tools which may have a lot more to offer the major crops here.

Efforts to advise on whether these new biotech tools should remain under GM legislation in the EU continue to be frustrated, as is the case with classical GM crops. An EU report on the topic was completed in 2012, but has never been published.

It is obvious that different countries want to advance this process. The Netherlands proposed that NBT plants should be exempt from current GM legislation. Sweden, Germany and Finland decided that CRISPR-Cas9 is a non-GM technique. And Ireland, the UK, Germany, Sweden and Finland have concluded that ODM-herbicide tolerant oilseed rape is a non-GM technique. Even EFSA indicated that cis-genesis is similar to conventionally bred plants.