Disinfectants prove to be an integral part of on-farm biosecurity
Using disinfectants as part of your cleaning regime is vital to minimise the spread of Panama disease. Research shows that various disinfectant products are effective in killing fungal spores that cause Panama disease.
Products listed in the table below are examples of disinfectant products which were shown to be effective when applied at 1% solution.
Before using any chemicals always check the current registration status and read the product label. A minor use permit is available for banana growers to use these products off-label (PER 86485) http://permits.apvma.gov.au/PER86485.pdf. Label and permit details can be accessed via APVMA website: www.apvma.gov.au
It is important to note that soil reduces the effectiveness of disinfectants. Different soil types have varying impacts on the effectiveness of the products. However, research has shown that once the equivalent of 1g of soil is present in 20mL of solution (1% product) then the effectiveness of products is compromised or reduced.
Investigations into DDAC products (e.g. Steri-maX®, Path-X™, Sporekill® made at 1% solution) has found that when there is no soil contamination, these products remain effective as a disinfectant after being exposed to sunlight, temperature and humidity for up to 12 months.
Quaternary ammonium compound test strips have shown to be an effective tool that measures the concentration of the active ingredient DDAC or BZK in disinfectant products. These easy-to-use test strips do not require dilution of the sample and are used by comparing the colour development on the test strip to the colour scale.
- DDAC and BZK disinfectant products used at the correct concentration and as per label or permit specifications (contact times) do kill the fungal spores that cause Panama disease.
- It is important to remove all soil and organic matter before applying any disinfectant product and replace solutions if they become contaminated.
- Easy-to-use test strips can be used to regularly test solutions in footbaths, spray shuttles and wash-down facilities.
This research was funded as part of project BA14013 Fusarium wilt Tropical Race 4 – Biosecurity and sustainable practices which was funded by Hort Innovation, using the Banana research and development levy, co-investment from the Queensland Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned not-for-profit research and development corporation for Australian Horticulture.
Test strips can help determine the effectiveness of your disinfecting solution
Disinfectant products that contain the active ingredient didecyl dimethyl ammonium chloride (DDAC – e.g. Sporekill®, Steri-max® and Path-X™) or benzalkonium chloride (BZK – e.g. Bactex, Agriquat) have shown to kill fungal spores that cause Panama disease.
For these products to be effective, it is important they are mixed at a 1% solution. Our researchers have investigated a range of test strips to measure the concentration of the active ingredient of disinfectant products used in footbaths, spray shuttles and drive-through dips.
High level (0 – 1500ppm) or extra high level (0 – 10,000ppm) quaternary ammonium compound test strips are an easy method of testing the active ingredient DDAC or BZK by comparing the colour development on the test strip to a colour scale.
For your information...
1% solution of 120g/L DDAC (e.g. Steri-max®) equates to 1200ppm
1% solution of 100g/L BZK (e.g. Bactex) equates to 1000ppm
1% of solution of 250g/L BZK (e.g. Agriquat) equates to 2500ppm *
*(either dilute and use high level test strips or use extra high level (0 – 10 000ppm) test strips)
For best results, make up a 1% standard solution of the DDAC or BZK disinfectant product you are using. This will allow you to directly compare the exact colour of a 1% solution to the colour of the disinfectant sample you want to test.
Keep this solution in a sealed container for future use.
It is recommended...
It’s recommended that you dip your test strip into the 1% standard solution and the disinfectant sample (e.g. footbath) simultaneously, that way you can compare colour instantly.
Dip test strips into the 1% standard solution and your disinfectant sample and remove immediately.
Immediately compare test strip to colour scale (maximum reading time of 5 seconds).
The colour of your disinfectant sample should be ≥ the 1% standard solution (as per image above with green tick).
- Use test strips to regularly check the disinfectant solutions in your footbaths, spray shuttles and wash-down facilities to ensure they are at an effective concentration (1% solution).
- Ensure there is less than 5% soil in footbaths and wash-down facilities – that is equivalent to 1g of soil to 20mL of disinfectant solution (1% DDAC or BZK product).
- Be aware that soil with a high clay content may have the potential to influence test strip results.
- Different water sources do not appear to influence the test strip results.
- With no soil present in your disinfecting solution, DDAC products prepared to a 1% solution are still effective at managing spores that cause Panama disease.
For more information about this work or for details on where to purchase the test strips contact the better bananas team –email@example.com or 13 25 23
There may be factors beyond the scope of the research that has been undertaken using the quaternary ammonium compound test strips which have the potential to influence results.
This trial was funded as part of project BA14013 Fusarium wilt Tropical Race 4 – Biosecurity and sustainable practices which was funded by Hort Innovation, using the Banana research and development levy, co-investment from the Queensland Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned not-for-profit research and development corporation for Australian Horticulture.
Are cleaning and disinfectant products corrosive?
Infrastructure such as footbaths and wash-down facilities are important components of effective on-farm biosecurity. Demonstration trials have been conducted to investigate the potential corrosive ability of various cleaning and disinfectant products on different metal surfaces.
Two demonstration trials were conducted and the same treatments were used in both. Products included a detergent made to a 10% solution (Farmcleanse), three products containing 120g/L didecyl dimethyl ammonium chloride (DDAC) made to a 1% solution (Sporekill®, Steri-max® and Path-X™), and water as a control. Both trials demonstrated the effects of the above products on five different metals; unpainted steel, painted steel, galvanised, aluminium and stainless steel (grade 304).
The first experiment consisted of the metals being completely submerged in solution for 8 weeks, whilst in the second experiment the metals were treated by being dipped in the solutions frequently (2-3 times a week) then exposed to field conditions (temperature and humidity) for a total of 12 weeks.
Outcomes of this research
The demonstration trials showed that the detergent and disinfectant products caused low levels of surface rust development over the 8-12 week period for the majority of metals. Unpainted steel was the most susceptible to surface rust development, while galvanised steel, aluminium and stainless steel were the least susceptible.
When submerged in solution, the detergent and disinfectant products did not corrode the metals significantly more than water alone. The water treatment also appeared to have similar corrosive abilities as the other products trialled in this experiment.
When dipped frequently and exposed to field conditions, all three disinfectant products appeared to be more corrosive on unpainted steel compared to the water and detergent treatments. Furthermore, the DDAC products had shown to be more corrosive on unpainted steel when dipped frequently as opposed to the submerged in solution application method.
Remember to always follow label directions for cleaning and disinfectant products. After the appropriate exposure time you can rinse metal surfaces with clean water to minimise the risk of rusting.
What did the corrosion demonstration trial show?
Submerged in solution
- Water appeared to have similar corrosive abilities as the disinfectant and QA products.
- The QA products appeared to be more corrosive than the detergent and water treatments with frequent dipping application.
Submerged in solution
- The paint bubbled and peeled across most treatments, with water only having the least amount of damage to the paint.
- Rust development was present on the cut edges for all treatments.
- The paint remained in good condition for all treatments.
- Minor rust development was present where there were chips in the paint.
- Rust development was present on the cut edges for all treatments.
Stainless steel (grade 304)
Submerged in solution
- The stainless steel remained in good condition for the duration of the experiment against all treatments.
- Rust development was present on the cut edges of most treatments with the detergent having the least amount of rust visible.
- None of the treatments appeared to degrade the stainless steel for the duration of the experiment.
- Rust was present on the cut edges of the stainless steel on most treatments but with the detergent treatment having the least amount of rust development.
Submerged in solution
- All treatments oxidised the aluminium with the exception of Steri-max®.
- The oxidised aluminium plates changed colour and developed a chalky texture across the surface.
- The aluminium remained in good condition for the duration of the experiment across all treatments.
Submerged in solution
- A white precipitate developed on the surface of the galvanised steel plates on most treatments, except the detergent.
- Rust developed on the cut edges of the galvanised steel plates treated with water.
- The galvanised steel remained in good condition for the duration of the experiment and across all treatments.
This trial was funded as part of project BA14013 Fusarium wilt Tropical Race 4 – Biosecurity and sustainable practices was funded by Hort Innovation, using the Banana research and development levy, co-investment from the Queensland Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned not-for-profit research and development corporation for Australian Horticulture.
How long are disinfectant products effective for?
Quaternary ammonium (QA) products have been shown to kill fungal spores that cause Panama disease. Our researchers have been investigating the longevity of three QA products that contain 120g/L of the active ingredient, didecyl dimethyl ammonium chloride. The QA products evaluated included Sporekill®, Steri-max® and Path-X™, at a 1% (1200ppm) solution.
So what did we do?
The QA products were placed in plastic storage containers outside (with the lids kept on) and exposed to field conditions (e.g. sunlight and temperature) for a period of 12 months. The high level (0-1500ppm) QA test strips were used as indicators to test the solutions on a regular basis, and at 4, 8 and 12 months intervals. At these intervals, small samples of the solutions were collected and inoculated with fungal spores of Panama disease race 1.
So what was the outcome?
The results showed that after 12 months exposure to sunlight, temperature and humidity, all three QA products were still effective at killing spores that cause Panama disease race 1. Testing at 12 months indicated a reduction in the concentration (using the test strips) for some of the QA products, particularly Path-X™. Despite the potential reduction, no colony growth was detected when samples of the three QA products were inoculated with spores of Panama disease race 1 in the lab. This result indicated that the products were stable, even after 12 months exposure to field conditions.
Good news for growers...
QA disinfectants used in infrastructure such as spray shuttles, that isn’t contaminated with soil and organic matter, will be effective for an extended period of time even when exposed to field conditions. However, always remember to schedule regular testing of your disinfectant solutions to ensure they are effective. This can be achieved by using easy-to-use test strips.
This research is part of the Fusarium Wilt Tropical Race 4 – Biosecurity and Sustainable Practices project (BA14013). This project is funded by Hort Innovation, using the banana research and development levy, co-investment from the Queensland Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.
Jeff has been working with bananas for the past 37 years as a research horticulturist with the Queensland Department of Agriculture and Fisheries based at South Johnstone. He is passionate about bananas and currently works on a number of important industry projects looking at disease resistance and agronomics of alternative varieties — particularly those varieties which have some tolerance to Panama disease tropical race 4.
Growing up in Brisbane Jeff completed his Master’s degree at the University of Queensland and has always had a hands-on approach to learning about bananas. In fact, prior to starting his career, he meticulously kept harvest data (weights, hands and finger numbers) for a stool of Lady Fingers in parent’s backyard. Some call this destiny!
Jeff enjoys Saba (Pisang Gajih Merah) bananas boiled in the jacket served with meat and vegetables and in his spare time enjoys fishing and playing tennis with friends and family.
Department of Agriculture and Fisheries
Centre for Wet Tropics Agriculture, South Johnstone, Qld
In order to fairly compare any treatment, a comparison needs to be made to a current or conventional practice, which is known as a control treatment. In this innovation trial, the control treatment is bare plots where herbicide is applied to control weeds as per normal farm practice. To account for any variation in factors such as sunlight or minor differences in soil characteristics, the trial treatments are blocked and randomised. In this trial each of the three double rows is a block and the 5 treatment plots are randomly assigned to different positions down each row. See figure below.
Within each treatment plot there are:
- 22 plants which measurements will be taken on — these are known as datum plants.
- 4 guard plants — which as the name suggests are a buffer between each of the treatment plots.
Alternative post-harvest product testing
Research has shown that a range of farm management practices have some incremental influence on disease management of crown end rot (CER), from site selection to irrigation practices through to packaging and dispatch. Specifically, good field and shed hygiene practices help reduce fungal spores making it easier and more effective for post-harvest fungicides to do their work. However, to reduce reliance on fungicide use and address issues associated with chemical resistance, research into potential alternative post-harvest treatments are being investigated.
Twelve post-harvest treatments including disinfectants, biological/organic treatments and alternative fungicides have been screened using clusters of bananas and observing the natural development of CER symptoms.
Crowns of each of the clusters were dipped in various treatments (for 30 seconds or 3 minutes), then ripened under standard ripening conditions. Once the fruit was ripened, the symptom development of CER was rated on a scale of 0-7 (7 being the most severe).
What are the results so far?
This initial screening has indicated that one fungicide (Fungicide B in the table below) appears to be better at managing some of the CER organisms than the currently registered fungicides.
The treatments that showed promise in this initial screening trial require further investigation on larger quantities of fruit and fruit from different production regions. This will help determine if they would be suitable candidates for post-harvest treatment in a commercial setting.
Some of the poorer performing treatments, including a biological product that caused severe fruit burn, will not be further investigated.
The table below provides a summary of the performance rating of each of the post-harvest treatments tested.
This work is funded as part of the Cause and management of crown rot of banana project (BA13011). This project is funded by Hort Innovation, using the banana research and development levy, co-investment from the Queensland Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.
The trial planted in early November 2017 has now started to bunch. Bell emergence commenced in week 14 and assessments are currently underway.
Innovation field trials
An exciting component of the industry’s National Banana Development and Extension Program is to apply different practices to banana plants which growers may not be willing to, or have the time to try on their own farms.
Established in November 2017 at the South Johnstone Research Station, the innovation trial consists of 390 Williams Cavendish tissue culture plants, planted as a double row configuration. Agronomic assessments, such as plant height, leaf emergence and bunch characteristics are being undertaken to help understand how different treatments affect the crop.
Click here for more information on the trial layout.
Ground cover treatments
The first of these treatments commenced at the beginning of November 2017, looking at some ‘out of the box’ ground cover management options for the bed.
The following images show the different ground cover treatments in the trial. These will be compared to bare plots with no ground cover. These photos were taken approximately 1 month after planting in December 2017.
Some initial observations from the ground cover trial have shown that plants planted into the black weed matting, appear to be shorter on average than the other treatments. However, there is no difference in average leaf emergence between the plants in the weed matting and other treatments.
Timing of desuckering
Other trial work underway is looking into two different timings for desuckering. Half the plants have had their first flush of suckers removed once there was at least 3 suckers 30 cm tall, at approximately 3 months after planting. The other half of the plants will be desuckered closer to bunch emergence.
Check back here for updates on the trial.
Have an idea for an innovation trial...
We appreciate grower’s knowledge and experience of banana production systems and are keen to seek feedback and advice on our trial work. We therefore encourage all growers who can contribute to our current trial work or have ideas on new innovative practices to contact our team: firstname.lastname@example.org or phone 13 25 23.
This work is funded as part of the National Banana Development and Extension Program (BA16007). This project has been funded by Hort Innovation, using the banana research and development levy, co-investment from the Queensland Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.
CJ19 has been irradiated and is in the process of stabilisation. Plants will be sent to the Northern Territory later in 2018 for planting at the Coastal Plains Research Farm.
CJ19 is a Cavendish selection originally from Indonesia. It is shorter in stature than Williams and is prone to choking in sub-optimal growing conditions. Varietal screening trials in the Northern Territory have shown that it is resistant to Panama disease tropical race 4 (TR4). Agronomic assessments of the plant crop conducted at South Johnstone showed that it has a slightly slower cycling time of approximately 12 months from planting to harvest, compared to Williams 11.3 months. It also produced a smaller average bunch weight of 15.9 kg compared to Williams 16.5 kg.
Mutagenesis, which is a breeding technique using gamma irradiation to increase changes in tissue cultured plants has been applied to cultivar CJ19. The aim is to develop an improved variety which retains its tolerance to the disease and with improved agronomic characteristics.
The first step in this process was to determine how much gamma irradiation to use on this variety. Too much irradiation can severely damage or kill the plant, and too little may not induce sufficient changes to the plants.
Experiments, known as dose response trials, have been conducted at the Maroochy Research Station and the sufficient dosage for CJ19 was determined.
CJ19 have been irradiated and are in the process of stabilisation. Plants will be sent to the Northern Territory later in 2018 for planting at the Coastal Plains Research Farm.
Check back on this page for progress updates on this trial.