Weeds can be frustrating for contractors in the spring, as they grow unpredictably and have safety implications if left to grow. These can include:
- Causing the ground to become slippery which can lead to pedestrian accidents
- Contamination of railways and therefore the possibility of derailment
- Threats to public health – some species are poisonous or can cause blisters and burns when touched
Because of these problems, it’s important for contractors to successfully control weeds.
Colin Mumford, technical manager at Envu, gives his top tips on how to get ahead with weed control with an integrated programme that focuses on pre-emergence weed control.
Preparing a control plan
Having a prepared plan is the first step to any successful weed control programme, as this will save time and money.
Each site will have its own unique set of challenges to deal with. In order to build a control programme and figure out which chemical and cultural control options would be most suitable for each site, contractors will need to identify:
- The types of weeds typically growing in the area
- The optimum growing conditions and temperatures for weed growth
- The time when weeds usually start to grow
- The accessibility to the site
Using pre-emergence herbicides
Pre-emergence herbicides are an incredibly important tool in the amenity contractor’s toolbox so should be considered by all in order to get ahead this weed season.
Pre-emergence herbicides can be applied prior to weed establishment or when weeds are small and will prevent weeds from developing further. Applications of pre-emergence herbicides should be made on clean surfaces, free from leaf litter.
As temperatures and weather conditions differ across the UK, some contractors may need to apply earlier or later than others. Understanding when weeds usually grow or if weeds are already present, how developed the weeds are will help contractors to formulate their own unique control plan prior to applying pre-emergence herbicides.
The benefits of pre-emergence herbicides
Pre-emergence herbicides provide a head start in controlling weeds, but they can also help to reduce herbicide use.
Tackling the weeds early means less herbicides will be needed throughout the entire growing season and this has positive benefits for the environment and the rising issue of herbicide resistance.
They also help customers to save money on herbicide use and can allow contractors to fulfil other job opportunities. This is because the residual control of the herbicides provides long lasting activity against weeds.
Valdor® Flex, is an example of a pre-emergence herbicide and can provide residual control against a broad spectrum of weeds, for up to four months.
It can be mixed with water and applied as a pre-emergence or if weeds are already established in can be applied in combination with Roundup® ProActive or ProVantage which will provide the initial knockdown, while Valdor Flex will offer the residual control.
Applications can be made all year round but only one application per site should be made per year. For best results, read the label, as this will advise on the target weeds, application timing and treatment rate.
If weeds do re-emerge during the season, then further applications of a non-selective herbicide such as Roundup® can be made.
Contractors should also consider pre-emergence cultural controls.
They are not always successful at offering long lasting control, but they allow contractors to get on top of weed activity early and support the work of herbicides.
Cultural controls at this stage would include keeping the area clean and tidy from leaf litter which helps to create a less favourable environment for weed growth.