Alkaline Hydrolosis

Alex Websterin Best of the Rest

Nissan Sprayer 1.JPGMore research and development goes into producing pesticides than ever before, so why do we still notice inconsistent performance of the same products when used by different operatives at different sites? This is a question that plagues both the turf manager and the bill payer when dealing with professional turf.

This article intends to set out one of the main reasons for poor pesticide performance and to offer suggestions as to how this can be overcome so that you, the user, may achieve better pesticide performance, save money and, ultimately, improve turf quality.

With the simple management of the pH of your spray tank water it is possible to improve pesticide performance and reduce the number of ineffective applications through the season.

The main area of focus for this article will be on the process of alkaline hydrolysis and the negative effects this has on the performance of pesticides. The way alkaline hydrolysis effects performance is by speeding up the time it takes for a product to reach its half-life. This begs a couple of questions; what is alkaline hydrolysis and what is half-life?

We will begin by explaining the latter, as the concept of half-life is a simple one. Half-life is a period of time for something to decrease by half, in this case it is a pesticide product and the decrease is related to performance. As you can expect, this means that when a pesticide reaches its half life it will become half as effective. So, we can directly relate the half-life of a pesticide being reached to a drop in performance of 50%.

The half-life of a pesticide will differ across various products but, depending on spraying conditions, this can vary between a matter of minutes and a few weeks.

You may ask what makes this so important but, when you look at the time it takes from filling a spray tank, mixing the product and completing the application to your turf, it will take anywhere in the region of forty-five minutes to an hour and a half, regardless of how long you want a product to last for once it hits the turf. In this time, if your product has reached its half-life then much of the spray solution you use will be far less effective, even to the point of being totally ineffective.

Fairway Landrover Drayton.JPGCommonsense decrees that this then becomes both a waste of time and money if you haven't managed to get the full effectiveness from your chosen product, and your turf quality will suffer.

So, where does Alkaline Hydrolysis fit into all of this? As mentioned in the introductory paragraph the pH of your spray tank water is an often overlooked factor when spraying a pesticide product. Weather conditions and timing are often cited as reasons for pesticide failure and, whilst these factors must be taken into account as they are imperative, by managing the pH of the water used in your spray tank it is possible to gain the maximum effectiveness from pesticides.

Alkaline Hydrolysis is the name given to the breakdown of pesticide molecules in high pH water. The active ingredients of a pesticide will undergo degradation in high pH water, so it is necessary to manage the pH of your spray tank solution before mixing in any pesticide.

The optimum pH varies amongst products but, in the case of most pesticides, they will retain their most effective form in acidic water and, by being able to achieve a pH of between 4 and 5.5, it will enable the user to gain greater effectiveness from pesticide applications.

The observations you could expect to make from pesticide applications, where the product has undergone alkaline hydrolysis, will be as simple as an all round poor result, with seemingly low uptake or control of the target site.

A good example of this would be in the case of a greenkeeper spraying a fungicide, who will have an efficient spray run mapped out before starting an application. The first four or five greens sprayed appear to have good control of the disease, but the last two or three haven't done as well or, perhaps, a quick return of disease might be observed on those last few greens as opposed to the first few.

This is down to the fungicide having undergone alkaline hydrolysis whilst in the spray tank. This would lead to further applications being required, or the need to carry out the application of other products or mechanical/cultural practice operations to help combat the disease.

Likewise, in the case of herbicide application or worm control, product longevity is often queried, and it can be explained by high pH water causing an early breakdown of the product and reducing effectiveness.

As was mentioned earlier, pesticide technology has advanced to such a stage now that products, when applied in optimal conditions, will work incredibly well, but it is important to manage all areas in your control, of which pH is a major factor.

There are various options available to help with the problem of high pH, and one of the most recent additions to the acidification market is 'pHassist Blush', distributed by Tower Sport (Europe) Ltd. This is a formulation of acid and wetting agent, combining to create a highly effective, low cost water acidification product.

It is a very potent acid, the product has a pH of 1, but it is totally safe to use on turf, it won't harm the operative if spilled and it won't cause corrosion to machinery. This potency is demonstrated in the application rate of the product where 1 litre will reduce the pH of 300 litres of water from as high as 8.5 to 5. A colour changing formulation also means that it is very simple to use, as the colour of your spray tank water will change, with agitation, from opaque to a light red, when reaching a pH of 4.

This means there is no need for calibration before hand or litmus paper testing of the tank when the product is applied. It is important to remember that your spray tank water must be acidified to the correct pH before applying your pesticide, so to avoid alkaline hydrolysis.

To reiterate the key points made about improving pesticide performance; alkaline hydrolysis of pesticides can cause a rapid decrease in the half-life time of a product. This means that the effectiveness of a product can be greatly reduced whilst sat in your spray tank water if your ph has not been managed correctly.

Always consult the application instructions for effective pesticide use, but also check the optimum pH of a product to gain the most effective results.

It is far better to maximise the performance of a single application than it is to repeat an expensive application at a time when turf quality must be at its peak, and budgetary management is key.

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