Tank-mixing products can help create efficiencies for your spray applications. When done appropriately, tank-mixing can reduce labour and equipment cost, and save time and energy.
However, chemicals have the potential to react with other substances. They can change the characteristics of the carrier water, and they can positively and negatively change the efficacy of products in the mix. It is very important to test the compatibility of products before mixing them, and avoid any combination that could prove phytotoxic to delicate turf plants.
There are a lot of variables to consider. Always check your product labels thoroughly, and conduct a physical compatibility test for all new tank-mix combinations. If in any doubt, contact the manufacturer for more detailed advice.
Potential positive effects of tank-mixing
Broaden the target spectrum: tank-mixtures can help you to control multiple problems with less applications.
Improve resistance: mixing products with different modes of action can help lessen the chance your application will lead to disease, insecticide or herbicide resistance.
You could achieve enhancement in your mix: when the mixed products deliver an improvement, compared to applying the product on its own. For example using an adjuvant like Agral for improved weed or mite control.
You could achieve synergism in your mix: when the mixed products combine and interact to produce more effective results than if they were applied separately. More pronounced effects often occur when combinations of products include complimentary modes of action, like Medallion Group 12 and Posterity Group 7.
Potential negative effects of tank-mixing
Chemical incompatibility, or antagonism: the opposite of synergism. When the mixed products combine and interact to produce less effective results than if they were applied separately. In addition to poor performance, an increase in plant phytotoxicity may occur.
Physical incompatibility: is the inability of your chosen products to combine together in a tank-mix. Can be caused by several factors, including improper mixing sequence, inadequate agitation, inadequate water carrier volume, poor water quality, or lack of stable emulsifiers in some emulsifiable concentrates, or even reaction between products. Common results are the development of flocculants, separation, curdling, gelling, or becoming sludge-like.
Increased resistance: it is important to rotate your modes of action with tank-mixes as well as with single products. If the same product combination is used repeatedly over a long period of time, there is the potential for resistance to build up, the same as if you use any single product repeatedly over time. This is more likely to occur when the actives in the tank-mix have the same mode of action (i.e. are the same chemical group). However resistance can also occur when using different groups in a tank-mix, if they are used frequently.
To reduce the potential negative impacts of tank mixing we can conduct a simple physical compatibility test, or ‘jar test’ to determine physical incompatibilities. Remember, it is still possible for some mixtures to be chemically incompatible, i.e. efficacy impacted, despite no physical evidence of mixing problems and if you need advice, talk to your local Syngenta representative.
In addition to compatibility testing, it is important to follow the formulation type mixing sequence to form a homogenous tank mix for spraying. If this order is not detailed on the label instructions, the rule is to follow wwwWALES:
Things to consider for best results when applying products
One of several things to consider is the recommended product placement; leaf, crown, thatch, soil. If the tank-mix you’ve put together has products that are applied to the same zone, for example they are both leaf/crown-absorbed, then they make a good choice to mix together. However, if one product is leaf-absorbed and the other root-absorbed, then there will be a loss of efficacy for at least one, if not both, of the products. You cannot spray the tank-mix on both the leaf and the soil without affecting the level of efficacy in each area. Your application should be targeted to the location of your pest, weed or disease for best outcomes and best efficacy.
For more information contact your local Syngenta representative.