The bat­tle against bracken, and why her­bi­cides bring prob­lems of their own

The Irish Times - Weekend Review - - ENVIRONMENT - Michael Viney Michael Viney’s Re­flec­tions on An­other Life, a se­lec­tion of col­umns from the past four decades, is avail­able from irish­times.com/irish­times­books; viney@anu.ie

Clasp­ing the stem firmly with both hands, I tug up fronds of bracken shoot by shoot. The last buried inches leave the ground so sweetly that it should be quite a sat­is­fy­ing task. What spoils it is know­ing how lit­tle it achieves. The stem parts with­out protest from an un­der­ground cabling of tough, black roots – a sin­gle plant of bracken can even­tu­ally spread to fill a whole field. Only cut­ting it year after year will even­tu­ally wither its vigour.

My to­ken tug­ging of the fern as it creeps in from the hedge is the re­flex of a gar­dener, now rather less vig­or­ous than it was. But for many hill farm­ers, watch­ing green waves of bracken roll down the higher slopes of land, its in­va­sion can seem a last dis­cour­age­ment.

Bracken hides sheep that bur­row after the last strands of grass. It holds ticks that can carry dis­eases, for both sheep and hu­mans. It sheds toxic spores that can pol­lute hill streams and piped wa­ter with car­cino­gens. And where it fi­nally shades out the grass a farmer must deduct the area from the graz­able land that earns the Euro­pean Union’s ba­sic farm pay­ment.

Iron­i­cally, fear of a can­cer haz­ard has also been hold­ing back fi­nal EU ap­proval of asu­lam, the one se­lec­tive her­bi­cide that kills bracken, roots and all. It was banned orig­i­nally through con­cern about the chem­i­cal’s safety when used on ed­i­ble crops.

This year, fol­low­ing “emer­gency” au­tho­ri­sa­tion of its sale by the Depart­ment of Agri­cul­ture, it can be used on bracken from July to Septem­ber. Much of the in­vaded land is too steep for spray­ing from trac­tors or even man­u­ally from knap­sacks, and aerial spray­ing is long banned by the EU. That is, in any case, a costly op­er­a­tion. Even with­out it, a 5l can of con­cen­trated Asu­lox (the brand name) costs ¤100.86.

Some blan­kets of bracken on our hill­side seem to have tre­bled in size. That goes, too, for dark thick­ets of rushes, flour­ish­ing ever more densely on damp land as cli­mate grows milder and wet­ter.

Left undis­turbed, a clump of rushes can grow more than a me­tre high. They flower this month in tufts that can pro­duce more than 8,000 seeds per shoot. And now the her­bi­cide MCPA, com­monly used for rush con­trol, is tox­i­cally con­tam­i­nat­ing wa­ter sup­plies and may in­vite an EU ban in its turn.

Along with rushes, MCPA can be used on rag­wort, docks, this­tles and net­tles. A map pub­lished in the Ir­ish Farm­ers’ Jour­nal last month showed pes­ti­cide con­tam­i­na­tion of wa­ter schemes county by county in 2015.

Sam­pled for Ir­ish Wa­ter by the En­vi­ron­men­tal Pro­tec­tion Agency, pol­luted schemes had more than dou­bled from the pre­vi­ous year, with the high­est rate in Co Mayo. Two-thirds of 61 schemes held MCPA. As Ir­ish Wa­ter has been telling farm­ers, just one drop can con­tam­i­nate an Olympic-size pool.

All this co­in­cides with the row about glyphosate, key in­gre­di­ent of Roundup, Mon­santo’s all-pur­pose her­bi­cide. A mil­lion or more EU cit­i­zens, it is claimed, have signed on­line pe­ti­tions against fur­ther ap­proval.

Roundup has been the farm­ers’ reg­u­lar weapon of mass de­struc­tion on ev­ery­thing from hill­side bracken to weeds in fields of grain due for har­vest­ing. World Health Or­gan­i­sa­tion re­searchers have termed it “prob­a­bly car­cino­genic”, gen­er­at­ing fierce ar­gu­ment be­tween en­vi­ron­men­tal­ists and Mon­santo chemists.

Residues of the weed­killer are com­monly found in bread and hu­man urine, and a fi­nal judg­ment on its use in food crops is soon ex­pected from the Euro­pean Food Safety Author­ity.

And then there are neon­i­coti­noids – “neon­ics” to the trade. These pes­ti­cides are now shown defini­tively to dam­age honey­bees and bum­ble­bees at ev­ery stage of their lives. An ex­cep­tion, it seems, may be where farm­ers grow enough pris­tine wild flow­ers, to give the bees an al­ter­na­tive, around their flow­er­ing but toxic oilseed rape.

This ap­pears to be so in Ger­many, whose bees, in re­cent field tri­als, were spared the harm of those on farm­land across the UK and Hun­gary. This ma­jor re­search was mostly funded by the pes­ti­cide man­u­fac­tur­ers them­selves, hav­ing re­jected ev­i­dence of

‘‘ Bracken holds ticks that can carry dis­eases, and sheds toxic spores that can pol­lute wa­ter with car­cino­gens

harm gained through lab­o­ra­tory tests.

The tar­get pests of neon­ics are aphids, suck­ers of plant sap and some­times with toxic saliva. A new Bayer in­sec­ti­cide, act­ing on aphids in much the same way as neon­i­coti­noids do, is flupyrad­i­furone, a chem­i­cal that also per­me­ates the plant and its pollen and takes months to dis­ap­pear in the field.

Claims that this is “safer for bees” are chal­lenged by en­vi­ron­men­tal groups, and although the chem­i­cal has been au­tho­rised by the Euro­pean Com­mis­sion, on­line pe­ti­tions were launched last year against its ap­proval by the Depart­ment of Agri­cul­ture’s pes­ti­cide-con­trol ser­vice.

The rules around us­ing pes­ti­cides grow ever more sub­stan­tial, at least on pa­per (and on­line). An EU sus­tain­able-use di­rec­tive (pcs.agri­cul­ture.gov.ie/sud) now re­quires ev­ery farmer or con­trac­tor us­ing a sprayer to reg­is­ter with the Depart­ment of Agri­cul­ture as a pro­fes­sional user and sign up for proper train­ing. Es­pe­cially, one hopes, in leav­ing ad­e­quate “no spray zones” around ru­ral wa­ter­ways and wells.

Bracken: a sin­gle plant can spread to fill a whole field. IL­LUS­TRA­TION: MICHAEL VINEY

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