Compatibility of chemicals – will this go with that?

Compatibility of chemicals – will this go with that?

Tank Mixing Chemicals

It’s always tempting to add a number of different chemicals to the spray tank and spray an area once, rather than spraying the same area or crop two or more times with different chemicals. Tank-mixing different chemicals can save you time, as well as the expense of travelling over the same area twice – unless of course, the chemicals are incompatible, in which case you’ve wasted time and money, and you’ve possibly also damaged your crop.

There are two types of incompatibility that we need to be aware of; physical and biological incompatibility.

Physical incompatibility happens when two or more chemicals react and the spray mixture changes physically; for example, the chemicals dissociate into two or more layers in the spray tank; or one or more of the chemicals precipitate and settle on the bottom of the tank; or they react to form a gel, globules or strands like spaghetti that block filters and nozzles.

Biological incompatibility happens when different chemicals appear to be physically compatible, but the results are unexpected; for example one or more of the chemicals doesn’t work, or maybe the chemical mixture damages the crop that is sprayed. The problem with this is that it may be up to several weeks before you realise that you had an incompatibility problem, and in that time the weed, pest or disease has continued to cause problems, or the crop yield or quality has been reduced.

How can we check the compatibility of different products before we mix them together?

  1. Firstly, check the labels of the products that you want to mix for advice on compatible/incompatible products.Be aware that label instructions may be brand specific. A farmer once told me that for years he had been spraying a tank-mix of trace elements and various glyphosate products pre-sowing, with no adverse effects. Then one year he tried a new brand of glyphosate herbicide and the spray mixture turned to a gluggy mess and had to be shovelled out of the spray tank.
  2. If there are no clear directions on the label(s), seek advice from a reputable agronomist or advisor, or from the manufacturers of the products.
  3. If you still can’t get the advice you need, you could try diluting small quantities of the chemicals to their normal application dilutions, then mixing them in a jar to see if they are compatible. Note there are some limitations to the ‘jar test':
    • You need to wait long enough after mixing the chemicals in the jar to allow them time to react. This may be as long as 15-20 minutes.
    • This procedure only tests for physical incompatibility, and gives no indication of whether the products are biologically compatible.

Be aware that it isn’t just the obvious situations where incompatibility can be an issue. For example, tiny amounts of Group B sulfonylurea herbicide (such as found in boom end-caps, recirculation/agitation systems, and nozzles filters) may have a ‘synergistic’ effect on Group A herbicides, causing crop damage where you wouldn’t normally expect it.

Mixing order is important. Check the correct mixing order with your advisor or a chemical manufacturer.

For many tank mixes, it is important to keep the mix agitated, so that it doesn’t settle on the bottom of the tank.

Cross-contamination of grain from fungicide-treated fertiliser

Cross-contamination of grain from fungicide-treated fertiliser

Mobile Silos

The Victorian Department of Environment and Primary Industries (DEPI) has reported two cases of grain contaminated with the fungicide flutriafol, where flutriafol-treated fertiliser had previously been used in equipment used to handle or store the grain.

In one case a farmer treated fertiliser with flutriafol as it was transferring via an auger to a truck. The truck was swept but the auger was not cleaned or decontaminated. Canola grain was later transferred via the auger to the truck, and when tested showed levels of flutriafol that was 17 times higher than the legal limit.

In the other case a farmer temporarily stored flutriafol-treated fertiliser in a silo, which was not cleaned before later being used to store wheat. The wheat was found to contain levels of flutriafol that are 42 times higher than the legal limit.

These cases illustrate how important it is to thoroughly clean and decontaminate equipment and facilities that are used to handle or store potentially contaminating materials. This does not only apply to grain, but to any food or feed that is handled or transported. Other examples include fresh fruit and vegetables carried in contaminated bins; and processing waste (eg citrus peel, brewers grain, etc) that is carried in trucks or bins and fed to animals.

Source: Chemical Industry News No. 76, produced by Victorian Dept of Environment and Primary Industries.

Smith & Georg provides Chemical Accreditation training for users of agricultural and veterinary chemicals. For more information go to or call us on 1800 991 985.

A new Online course is launched

A new Online course is launched

Smith & Georg recently launched ionlinecoursets second online course, Control Weeds. This means that people in Queensland who need a Commercial Operators Licence, commonly known as the ACDC Licence (Agricultural Chemicals Distribution Control Licence), can now complete all the training for that course online (they also must complete the Chemical Accreditation course, which is already available online).

This is great news for people who live in remote areas and who may otherwise have to travel considerable distances to attend a training course. It is also great news for people who are time-poor and find it difficult to leave their business to attend a 1-2 day course.

Online courses can be done entirely at home or at work, in fact anywhere where there is a computer with good internet connection. Once enrolled in a Smith & Georg Online course, the participant can log onto the course at any time of the day, 24/7. There are no limits on how often a person logs onto the course, how long they stay logged on, or how long it takes to complete the course. And there is good personal support for course participants via phone and email.

For more information, or to enrol in an online course, call Smith & Georg on 1800 991 985, or go to

Complying with droplet size restrictions when spraying tree and vine crops

Complying with droplet size restrictions when spraying tree and vine crops

This spray drift restraint statement is familiar to producers who spray broadacre crops with boomsprayers. What’s different about this one is that it is taken from the label of Vivando® Fungicide, which is registered for use on grapevines. An identical statement appears on the label of Movento® Insecticide, which is registered for use on citrus and mangoes.

Vivando Label

This is a mandatory statement, which means it is illegal to apply these products with sprayers that produce fine or very fine droplets.

For years we’ve been told to maximise coverage of crops by applying sprays to trees and vines with fine droplets; now we’re being told to use medium or larger droplets in order to minimise spray drift onto non-target areas.

How can producers with tree or vine crops comply with this label requirement?

If your sprayer has hydraulic nozzles, check with the nozzle manufacturer about the droplet size produced by your nozzles. Most nozzle manufacturers and suppliers have charts of spray droplet quality (ie droplet size) for various nozzles at different spraying pressures. It may be as simple as changing nozzle type or size, or pump pressure, to comply with label requirements. The photos show a reduction in drift from an airblast sprayer by changing from conventional nozzles to air-induction nozzles, combined with a drift-reducing tank additive. (Photos provided by Plant Protection Chemistry New Zealand Ltd)

Conventional Airblast Sprayer
Conventional Airblast Sprayer with conventional nozzles
With air-induction nozzles and drift-reducing adjuvant
With air-induction nozzles and drift-reducing adjuvant

If you have an air-shear sprayer, seek advice from the manufacturer of your sprayer.

For more information, or to enrol in an online course, call Smith & Georg on 1800 991 985, or go to

Do you wear white when spraying? Consider wearing yellow!

Do you wear white when spraying? Consider wearing yellow!

Most of us are familiar with the white Tyvek® disposable coveralls. In some workplaces employees are expected to wear these coveralls when handling and applying chemicals. They provide good protection from accidental exposure to most chemicals that we are likely to come across in farming and land management situations; however they tear quite easily and it’s not long before they need to be discarded and replaced with a new coverall.

DuPont, the manufacturer of Tyvek® coveralls, also produces the yellow Tychem® garments. As well as meeting the USA EPA requirements for a ‘Chemical Resistant’ suit (which Tyvek® does not), Tychem® garments are tougher than Tyvek®, and can generally be used for a much longer period of time before they need to be replaced.
Where there is a high risk of exposure to a chemical (for example when spraying in enclosed areas such as glasshouses), a higher level of personal protection is required, such as that provided by the Tychem® coveralls.

Be extra careful if using either of these coveralls in hot weather, and take precautions to avoid heat stress.

You may be able to purchase Tychem® coveralls from your local supplier of chemicals, or from a specialist safety store. If you can’t find anyone local who stocks them, contact Complete Ag and Seed Supplies on 08 8380 9400, who can supply and mail them to you.

Person wearing white coverallsPerson wearing yellow coveralls

Get rid of those unwanted chemicals!

Get rid of those unwanted chemicals!

unwantedchemicalsMost of us have a few part-drums of chemical lying around the place (hopefully in a safe, secure, storage area) that we will never use again; either because it’s out of date, or it’s no longer registered, or because we simply have no further use for it.

ChemClear is a program run by the chemical industry, with the aim of collecting unwanted chemicals and disposing of them safely. Did you know that:

  • ChemClear now has permanent collection depots in Sydney and Melbourne that open for one day each month?
  • There will be some regional collections in rural Victoria in March?
  • There will be a collection in South Australia in mid-2014, and you are asked to book your chemicals into this program by the end of March?
  • There will be a collection in Tasmania in the next few months?

For more information and to book your chemicals into any of these collections, go to, or call 1800 008 182.

South Australian users also have the option of disposing of unwanted chemicals through the EPA’s Zero Waste SA Household Hazardous Waste program, which is free for householders and primary producers.

For more information, or to enrol in an online course, call Smith & Georg on 1800 991 985, or go to

Just out of interest!

Just out of interest!

In December the Australian Pesticides and Veterinary Medicines Authority (the APVMA) released interim sales figures of agricultural and veterinary pesticides in the financial year 2012-13.

Total sales of agricultural products was around $2.282m; of which $1.258m was for herbicides, $348m for insecticides, and $169m for fungicides.

Total sales of veterinary products was around $937m; of which $423m was for control of internal and external parasites, and $135 for injectable vaccines. The sales figures include products used on pets as well as farm animals. For example, $52m was spent on ‘Dietary/therapeutic pet foods’.

Excerpt from the APVMA Gazzette, No. APVMA 24, Tuesday, 3 December 2013