Every selective herbicide is based upon an active ingredient(s). It is these active ingredient(s) which have activity against the target weeds.

SUPERTOX 30, for example, contains two active ingredients 2,4-D and mecoprop-p.

All active ingredients must demonstrate proven levels of efficacy and safety.

Only those active ingredients which conform to all the strict legislation governing pesticide registration will gain approval.

The flow chart on the following page demonstrates how an active ingredient is tested. On average, 10,000 potential herbicides are tested each year by Bayer. Initial screening will test the potential of the herbicide to control the major weeds of the world, whilst having no effect on the major world crops - rice, cotton, maize etc.

When an active ingredient shows potential, the crop and weed spectrum will be widened.

Alongside this stage of research into efficacy, safety studies as described earlier, will be under way.

Those potential candidates which fail to meet the extensive safety testing will proceed no further.

From the 10,000 potential active ingredients tested yearly, only about 150 will be tested at commercial dose rates.

From these 150, on average only 20 of the original potential candidates will proceed into field studies.

So strict is the legislation governing the potential development of an active ingredient that from the 10,000 potential candidates per year, the industry average for approval is only one new active ingredient every 10 years, or one from 100,000.

The active ingredient must be presented either alone or in combination with other approved actives, into a product which is stable in storage, can demonstrate efficacy in its use area and is available to the user in a format which enables effective application.

This is the process of product formulation.

No active ingredient will ever be developed purely for use on turf. Such is the huge cost of developing a new active, initial development is always focussed on the major world crops.

Only once an active has approval, studies will be initiated for other areas such as turf.

Taking the example of SPEARHEAD. The active ingredient diflufenican was first approved in the UK in 1986 for use on cereals.

In 1987 Rhône-Poulenc Amenity, knowing the activity of diflufenican against weeds such as speedwell, took the active ingredient and developed many formulations, the specific aim being a broad-spectrum turf selective herbicide.

It took a further EIGHT years of turf specific research to gain approval for the product SPEARHEAD.

In summary, EVERY active ingredient must be approved and in addition EVERY individual product must also be approved for its specific area of use.

Approved products carry the MAFF or the new MAPP number.