Until relatively recently, many users have been nervous of tank mixing liquid products together. Mainly, I suspect because of concerns of scorch or damage to turf. It is also the case that amenity pesticide product labels do not provide much information on recommended tank mixes, leading to the belief that if it is not on the label it is not allowed. In truth, many products can be tank mixed. Exceptions are where two or more anticholinesterase compounds are to be combined (this will be shown on the product label) or if the label specially prohibits tank mixing. It is also illegal to mix a pesticide with an adjuvant which is not on the authorised list.
In fact, questions about tank mixing are some of the most frequently asked of us. So what are the advantages of tank mixing? Firstly, you can carry out more than one operation at a time. A good example would be the combination of Headland Relay Turf, a selective herbicide with a suitable soluble or liquid fertiliser. An easy one to show the benefits of weed and feed in one application, rather than having to apply two separate sprays.However, care and good advice is needed.
What about a selective herbicide and soluble iron sulphate? Many herbicides are not compatible with iron sulphate, so unless you have a passion for cleaning out your sprayer I suggest that you understand carefully which products can be mixed with iron in this way. In our case, speaking to your technical advisor or checking the company's tank mix information should avoid such problems.
Secondly, the use of approved adjuvants can often enhance the activity of a pesticide, resulting in more efficient weed control, or maybe the control of a specific weed that would not be as susceptible to the herbicide alone. Certain adjuvant chemistry may help with the penetration of insecticides into the soil, helping to combat turf pests. Sometimes, avoiding tank mixing can mean that you are not making the best use of the available tools for effective turf management.
The law regarding tank mixing of pesticides is outlined in the Code of Practice for using Plant Protection Products and it is also important to read the product label for any restrictions. Pay particular care to your protection by wearing the highest obligations of protective clothing stated on the product labels.
Another area to consider is whether the intended volume of water and spray quality for each product are similar. For example, mixing a foliar fertiliser that is applied in 300 litres of water per hectare with a wetting agent applied in 600 litres per hectare will probably mean that most of the fertiliser will be washed off the leaf and be rendered ineffective if applied at the 600 litre rate. An example where tank mixing may not provide the benefits the user is looking for.
Just as important, is the sequence of tank mixing. We know through our extensive testing of tank mixes that the order mixing products can be vital, often making the difference between compatibility and incompatibility. In general, after filling your sprayer to at least 70% full, add the hardest products to get into solution first, i.e. soluble powders and then liquids. (Not the other way around). If uncertain, check with the manufacturer. We give guidance on the correct sequence on our tank mix chart information.
Here is the ideal tank mix sequence: Fill sprayer 70% full with water >> add any water conditioner (such as Transport Ultra)>> Add any soluble powders or WDG's (water dispersible granules). Allow time for complete dispersion of soluble powders in the spray tank >> Add any liquid products >> Add any adjuvant and fill the spray tank up to full volume.
Finally remember, that physical compatibility is not the same as biological compatibility. Just because one or more products will physically mix together, does not mean that they will not cause damage to turf. It is worth remembering that some mixes will be fine when there is adequate moisture in the soil but during hot, dry conditions this may not be recommended. Always consult your technical advisor if in doubt.
Tel: +44 (0)1223597834 - Fax: +44 (0)1223598052 - www.headlandamenity.com