Why spray them all?

By John Cussans

John CussansIt’s easy to make bold statements about the level of herbicide use by the industry as a whole – and such messages are taken up by many political lobbyists.

The conundrum is that it’s very hard to say exactly how an individual agronomist or farmer could sensibly reduce their use.

We know much about the impact on crops of individual weed species, and overall it seems the level of weed control (and so herbicide use) is too high to be justified purely on economics.

Recent trials in winter wheat by ADAS and ourselves found that in more than one-third of the nearly 200 comparisons carried out, weed control could not be currently justified.

So why are almost 100% of arable fields sprayed with herbicide – often more than once?

Not all weeds are the same, but that’s a secret we seem to be keeping from lobbyists.

Some species can easily be tolerated. Others, like blackgrass, wild oats, ryegrass and cleavers, cannot.

We shouldn’t criticise others while not remembering this basic principle ourselves, namely that not all weeds are the same and we must focus on the most damaging species.

What justification is there in chasing that last little bit of poppy, mayweed or groundsel?

Ben says: “He’s probably right, but one year’s weed is 10 years’ weed seed. I suppose it depends on how long a view you put on economic viability. I would be interested to hear the views of our end markets.”

Have your say on this issue on our weeds forum

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