Issues relative to Weed Control today

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Issues relative to Weed Control today

By Richard Minton

Many changes have taken place in recent years in the methods of weed control, due to changes in products available, application technology plus strict legal and Health and Safety compliance. Consequently, weed control has become very much a specialist and skilled operation needing careful planning of programmes to give the high standard of results expected today. The information below summarises many of the benefits and issues associated with chemical use for the control of weeds in an ever changing environment.

Why we need weed control:

Safety Efficiency Aesthetic value
Weed growth can:-
  • Obscure warning and direction signs
  • Reduce and obstruct visibility for drivers
  • Disrupt and raise tarmac, concrete and paved areas, creating trip points.
  • Clog drains, leading to flooding, possible aquaplaning by vehicles.
  • Create a fire hazard
  • Harbour rats and mice.
  • Disrupt playing surfaces.
Herbicides will improve efficiency by:-
  • Greater areas covered per day than hand or mechanical cutting
  • Giving longer lasting control
  • Reduces need for maintenance work and reinstatement paths etc
  • Avoiding physical damage to trees and shrubs caused by strimmers.
  • Eliminate risk of injury to operators of mechanical equipment.
  • Keeping waterways clear, improving flow and reducing flooding.
The use of herbicides, fungicides and insecticides will:-
  • Remove unsightly weeds
  • Improve the growth of trees and shrubs
  • Eradicate weeds, diseases and pests in turf
  • Clear weeds that trap unsightly rubbish
  • Improve the appearance of unkempt areas, discouraging vandalism.

Public Health

Legal requirements


Herbicides can eliminate vegetation in waste areas that harbour vermin.
Insecticides can control disease bearing pests such as fleas, flies, cockroaches and mosquitoes.
The Noxious Weeds Act (1959) requires landowners to eliminate scheduled weeds such as ragwort, various thistles and docks to prevent their seeds contaminating neighbouring land.
The Wildlife and Countryside Act (1981) specifies the control of certain plants such as Giant Hogweed and Japanese Knotweed.
Ongoing research indicates that by the careful use of pesticides, local authorities can effectively maintain footpaths and amenity areas at considerably less cost than alternative manual or mechanical methods. (See "Pesticides in the Community - A Guide to the Cost Benefits")

Cost comparisons:

Pavements, typical Local Authority needing to maintain 600 kilometres of footpath, average width 2m (annual treatment)

RMCWCpavements01-sm.jpg Method per km per 600km
Hand weeding £1,200 £720,000
Steam £400 £240,000
Infra-red (burning) £300 £180,000
Herbicide £50 £30,000

Shrub beds:

A basic herbicide treatment to shrub beds, tree bases etc. would generally include an early spring application of a residual product, followed during summer if necessary by two spot treatments of a non residual product. The cost of such a programme is about £20 per 100m²
To maintain a similar standard of weed control in these types of areas by hoeing manually would require monthly operations for six or seven months at a cost of £85 per 100m² per annum.

Reduction and Restricted Use of Active Ingredients:
Since the withdrawal of residual products (atrazine and simazine) for use on hard surfaces in the 1990's, weed control methods have had to adopt a more re-active approach rather than preventative. A certain amount of weed growth has to now be tolerated to allow the application of contact herbicides (Glyphosate) on a far more regular basis (often 3-5 times per year) Certain products are available for use on hard surfaces, such as Diuron, but this does not give the longevity and care has to be taken re application near drainage channels.
Other products have total weed control and residual properties but restrictions as to their area of use, not near water, not near trees and shrubs mean their uses in amenity situations are limited.

Restricted sales of herbicides for aquatic weed control are only now starting to take effect. The only method recommended for the control of Crassula Helmsli (a prolific growing and problem weed) is the active ingredient Diquat, only stocks still in the distributor network remain to be used, no further sales will be made.

Market Influences:


The agricultural market dominates the pesticide market, accounting for 97% of usage.
The major chemical manufacturers are therefore inclined to channel R&D monies into development of products for this market, amenity becoming reliant on spin offs! The size of the amenity market also dictates higher prices, with less volume being sold, manufacturers need to recoup R&D, plus registration costs by increased prices verses the agricultural equivalent. Amenity contractors have to justify these higher chemical costs when being compared with an identical agricultural product.

Amenity work carries a much higher public profile than other markets, due to the areas of work, pavements, roads, parks, sports pitches etc. Products therefore come under the spotlight, banning them or restricting their use seem to be the approach rather than justifying the benefits they produce as stated in the opening section "Why we need weed control"

Toxicity Comparisons:

Comparing the chemicals used for weed control with many everyday products is one way of alleviating the public fears as to their safety

Compared with Glyphosate (the most widely used chemical)

• Coffee is approximately 30 times more toxic

• Paracetamol is approximately 22 times more toxic

• Vitamin A is approximately 3 times more toxic

• Dandruff shampoo is approximately 40 times more toxic

• Pepper is approximately 7.5 times more toxic

• Salt is approximately 2 times more toxic

• Nicotine is approximately 113 times more toxic

Customer Expectations/Priorities:

Since the demise of residual products, it has often proved difficult to convince customers of the need for regular treatments rather than the once a year they might have enjoyed in the past. More treatments mean added costs and with budgets being cut rather than increased, pressures are put on Local Authorities to prioritise. Where does weed control fit compared to schools, hospitals, roads etc? We can stress the importance of weed control but the budgets have to be there to allow it to happen.

Planning your weed control:

The weather plays a major part in effective weed control. Working with a reputable contractor on a planned season long contract, to maintain a satisfactory level of weed control, reduces the need to adopt a fire fighting approach that can often be more expensive, and less effective.


Hard standing areas, pavements, car parks, driveways etc need to be treated between two and four times a season depending on the level of control required, using a systemic herbicide which is translocated throughout the whole plant. The weeds need to be actively growing to absorb the chemical so timing is critical; control is more effective on new young growth.

Selective weed control is vital for maintaining quality grass areas for people to enjoy. Whether on sports pitches, bowling greens or lawn areas, grassRMCWCsprayingfrontmillium.jpg

Other work where accurate application of products is essential includes moss control, grass growth control, insect control and fertiliser application. This work can all be undertaken by an approved contractor and can be built in to a planned programme of work.

Planning a weed control programme, reviewing it regularly as circumstances, methods and products do change, working with specialist contractors who have all the necessary skills and qualifications, will ensure satisfactory results. Carefully planned to gain the maximum benefit from the products being used, linked to other activities such as road sweeping and mowing, will give value for money, saving on the cost of repairing the damage that weeds can do.


Problems Positives

Loss of actives will lead to weeds becoming immune to the few remaining.

Higher costs due to increased number of applications.

Loss of aquatic herbicides will lead to drainage and flooding problems. Fishing and water sports will be effected.

Poor worm control will ruin winter sports, football pitches and golf courses especially.

Weed control remains a low priority, how to raise the profile.

Legislation is in place, unfortunately there is little or no enforcement due to lack of resources within the HSE.

Legislation should ensure all operatives achieve minimum standards. Clients should demand to see all legal, H&S and insurance data.

Investment in improved application technology, targeting only the weed, has led to more efficient use of pesticides.

Equipment such as Weed-IT - The Latest Technology in Pesticide Application.

Computer Controlled Spot Weeding Technology

  • Targets only the weed
  • Chemical savings of 60-80%
  • Spray canopy allows operation in windy conditions
  • Reduced exposure - equals safety to bystanders and operator
  • Improved productivity
  • Improves public perception of weed control
  • Enables local authorities to meet objectives of their environmental Policy


As mentioned at the beginning weed control is very much a specialist operation, governed by strict legal and health and safety compliance. Weed control programmes are better planned over a number of years, 3-5 as a minimum; this allows investment in the advanced application equipment and fully trained operators. In general careful planning of programmes will give continuity and the high standard of results expected today.

Product stewardship must remain the number one priority when applying chemicals. It is essential that the most advanced application technology is used and that all legal plus health and safety guidelines are followed to the letter.

For any further information please contact Richard Minton at Complete Weed Control, Head office 01451 822897, mobile 07760166689.or email

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