So, this guy comes over to me, puffing out the last of his cigarette, “What are you spraying?” “Confidor,” I reply.
“Oh, I don’t use chemicals, I prefer a more natural approach,” he says.
I ponder whether I should respond that the active ingredients are related to nicotine as he drops his butt…
Today our environment is, rightly so, on everyone’s minds – from concerns over the exponential use of Roundup to moves to ban Confidor – our most basic horticultural practices are being questioned.
Yet, we need to keep a clear head, continually reviewing the latest research while also weighing up and eliminating any potential risk to the contractor, others and the environment.
Glyphosate vs. Humanity Roundup was first developed by Monsanto as a herbicide in 1974. The US patent for the active ingredient, glyphosate, ended in 2000 leading to the rapid growth of all those lower priced, generic products.
In 2015 glyphosate was classified as, “probably carcinogenic to humans” by the World Health Organisation’s International Agency for Research on Cancer. Our own regulatory body, the APVMA, reviewed the herbicide in 2016 finding, “no grounds to place it under formal reconsideration.”
By 2018 potential dangers with glyphosate hit the world stage when a US jury found that Roundup had caused the cancer of a school janitor. Reportedly, there are now around 13,000 American plaintiffs preparing to sue Bayer who acquired Monsanto in 2018.
Canada and Brazil have reconfirmed regulatory approval of the herbicide after reevaluating the product, finding that, “glyphosate is safe to use and presents no risks to users when used in accordance with label instructions.”
And, there’s the rub – with uncertainty around the product’s safety and prospects of future litigation, it is essential that we all follow the instructions, making sure our work, health and safety procedures are sound. Workers need to be well trained and certified – chemcert.com.au lists the qualifications required, although there may be a need for additional certification in some states.
However, glossy chemcert cards and folders of SWMS gathering dust in the work shed are not enough. It’s important to ensure staff always kit up in the correct PPE and that areas are sign-posted and cordoned off when spraying in public. All this should be followed up at the end of the day with thorough documentation of all procedures. It’s a lot of work to “spray a few weeds” but a small price to pay to protect others.
Glyphosate Vs. The Environment
The soil microbiome is an incredibly complex world. Plant roots rely on an elaborate system of bacteria, fungi, earthworms and minerals to produce healthy above-ground growth. So, can targeted weed spraying also make surrounding plants sick?
Well, the jury is still out on this one! To date, studies around the impact of glyphosate on soil micro-organisms have produced contrasting results. Some studies have found adverse effects on particular mycorrhizal fungi, which improve the uptake of water and minerals as well as providing resistance to pathogens.
Another study suggested that repeated spraying of glyphosate caused a shift in microfungi species towards those more resistant to exposure.
Earthworms are ‘soil engineers’, processing organic matter in their gut, which produces nutrient rich, mineralised casts, while their burrowing enhances root penetration and water infiltration. They carry out these tasks 24/7 – if they ever form a union, we’re all doomed! So, earthworms and glyphosate; two studies found no negative impacts while at least six other studies found damaging effects.
Bayer states that Roundup has “little or no soil residual. It is rapidly bound by clay particles in the soil rendering it inactive.” Yet, several studies have found that the level of sorption depends upon the characteristics of the soil. There also needs to be research into the effects of any possible build-up of APMA in the soil (a chemical produced when glyphosate is broken down). APMA is considered mildly toxic to plants.
With 6.1 billion kilograms of the herbicide being applied worldwide in the last decade, the need for increased, impartial research is essential. The key message to take from all this controversy is to be aware and cautious. It may be time to review weed control programs and look for alternatives wherever possible.
Alternative Herbicides
‘Slasher’ is one of the newest products commercially available. It is the first organically registered pelargonic acid herbicide processed from plants.
Manufactured in Australia by Organic Crop Protectants, who were acquired by Yates in 2018, this product contains nine carbon atoms and is also called nonanoic acid.
Other alternative herbicides use various ‘natural’ ingredients such as horticultural vinegar, salt, pine oil and even clove oil. Yet, even ‘organic’ chemicals, whose purpose is to kill something, can still have a negative impact on other non-targeted organisms.
The biggest problem with these ‘burn down’ herbicides is that, unlike glyphosate, they are not systemic – the chemical is not translocated to all parts of the weed including the roots. Using alternatives to glyphosate may require more than one spray to eradicate weeds with strong root systems or more frequent spraying to keep on top of weeds before they can establish.
Hot Vapour Generators
A number of councils, including Byron Shire Council in NSW, have trialed steam weeding as an alternative weed control method.
There are a number of steam weeders available in Australia. Weedtechnics models were reviewed in this magazine in the November issue. Their equipment superheats water to 120 degrees Celsius using a mixture of saturated steam and boiling water, which is applied to he basal regenerative tissue of plants. The vapour also heats up the soil surface enabling the hot water to penetrate all the way to the roots. Weeds wither and die with no chemicals and no residuals. In an increasingly environmentally aware world, this may well be the golden ticket! Will there be a growth of green weeding contractors? Stay tuned.
There are also gas flame wands available that burn weeds on contact. Setting fire to weeds in the hottest, driest continent? Enough said… Weed control. Where to now? We all know that the safest path is to eliminate risk and if this cannot be done, to limit risk to the user, others and the environment.
Yet, banning chemicals used in targeted weed programs will create problems, particularly for bush regeneration, where chemical usage is seen as a necessary evil in the fight against highly invasive weeds that are destroying vast areas of ‘good bush’.
Eco-Friendly – Really?
Besides its contents, the green credentials of any herbicide should be judged against the embodied energy used during its manufacture and the ability (of the packaging) to be recycled It’s not easy being green – Part 1, Jul/Aug 2019).
Richgro are pioneers in sustainability – their plant in WA uses food waste to generate power, meaning all of their electricity is carbon free. Since joining the Australian Packaging Covenant in 2005 they have worked to ensure that all plastic packaging is recycled or recyclable. To misquote Henry David Thoreau, “What is the use of a landscape if you don’t have a decent planet to put it on?” In shaping the land, we should continually try to find the safest approaches. It’s certainly never easy being green!