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Producing ‘Fine Cotton’

The are two big ‘Q’s of cotton production – the quantity and quality of the crop that contribute to the gross return.

There are many factors over the duration of a season that contribute to each fo these ‘Q’s – requiring an agronomic juggling act of management, timing and luck.

These past season has seen the scourge of low micronaire – predominantly in the more southern growing regions of Australia. Growers across these valleys saw significant discounts of between $50 and $100 per bale due to low micronaire.

Micronaire (or ‘mix’ as it is commonly referred to by industry) is a measurement adopted by the cotton processing sector to define cotton fibre linear density or ‘fineness’. Based upon the air resistance presented by the fibre being tested when subjected to set pressures, it is a function of both the linear density of the fibre, and its maturity. (Long et al, 2013). While it is a standard measurement for the industry, sometimes confusingly, it no longer appears with units. The cotton trade however, presents these gradings in the following scales.

>= 5.3G7
5.0 – 5.2G6
3.5 – 4.9G5
3.3 – 3.4G4
3.0 – 3.2G3
2.7 – 2.9G2
2.5 – 2.6G1
<= 2.4G0

The goal for a grower and their consultant is to deliver bales between the premium range of 3.8 to 4.5, but ideally not outside 3.5 to 4.9.

So, unlike a lot of other fibre parameters, micronaire has a ‘Goldilocks zone’ where you neither want to be too high or too low. A high micronaire fibre (4.5 and above) will produce course yarns with fewer fibres in its cross section. Lacking in tensile strength, the resultant yarn can be weak. Due to its coarseness, this cotton is used to produce our denims and course blends (for added strength).

Low micronaire cotton is prone to knots and makes the ‘process’ slow (and frustrating). The finished product is often not perfect. While the resultant yarn is indeed finer, the knots (knows as neps) formed by tangling and knotting, do not allow for uniform dye uptake.  They result in the white ‘balls’ we see on cheaper textiles that dominate chain stores. Anyone who has ever tried to brush a toddler’s hair in the morning will understand the problems that come with a fine fibre.

Micronaire is not just a southern issue – in previous seasons growers in northern and western regions have suffered equally disappointing discounts for high micronaire. Micronaire is a big issue for the Australian industry. By understanding how day degree accumulation affects cotton micronaire, growers and consultants can best manage their crop to the seasonal conditions experienced each year.

A major factor in determining micronaire is temperature during the mid and latter stages of boll fill. To this extent, some will argue that control of micronaire is beyond the scope of the grower and the consultant. The fact that not all crops in the southern regions were impacted by the problem last year would suggest otherwise. Good agronomic advice may not remove the issue, however it can reduce how much of the crop is affected and to what extent. So how can we as advisors help influence this final figure?

As micronaire is largely a function of boll maturity, this our main control point. Managing the number of immature bolls at crop cutout, is the key factor. Our southern growing valleys are limited by a major environmental factor when it comes to this issue – a shorter growing season with less hot days to finish off the crop. Thus, was the situation last season when we saw an extended period of mild weather and low degree days, when the crop was requiring heat to continue maturing.  If this was the only factor that caused the problem, we would have seen a complete southern downgrade. It is important to ask then why was that not the case?

Obviously, some did things differently and avoided the low mic discounts at the end of the season. At the pre-planting, this may have been changing to a variety like 714B3F when planting in the back half of the planting window.

Post planting however, there is also much the advisor can do, particularly in relation to decision making around timing of crop cut-out.

This lays the foundation for the harvesting of all the fruit which has set on the plant. Due consideration must be given regarding the last effective square on the plant. This is the time in the crop when management decisions must be made, which in turn relates to the last effective flower and harvestable boll. A crop left to grow out too long may feature a high portion of fruit that isn’t physiologically mature at defoliation time. CottASSIST data for Carrathool this year showed the average day degrees per day for May was 2.7, April 5.2 and March 7.2; late maturing bolls were visually observed in the crop to stall in their development. To put it into perspective a flower requires 750 day degrees to become an open mature boll.

Figure 1.
Figure 2.

The decay in day degrees at the back end of the growing season is marked. Figure 1 and figure 2 are from a crop of 746B3F and 714B3F this year in the Carrathool region. Both figures show bolls that were tagged with the date in February when they became a flower, while the photos were taken when assessing the crops for defoliation at the very end of March. Both figures demonstrate a big difference in boll size and therefore maturity, for only two or three days difference in boll age. Timing of crop cutout is critical, and every day missed can add multiple days onto maturity of the crop at defoliation time.

Figure 3 shows a 748B3F boll, again in the Carrathool region cut open on the 16 April. This boll was a flower on the 13 February and is only just physiologically mature in the middle of April, a time most would agree to be the back end for defoliation to begin. The boll has no jelly or unformed cotyledons in the seed, however the seed coating is only just starting to turn dark, a sure sign of maturity. This particular paddock of 748B3F grew to be 110cm tall and after slow early season growth did not want to stop growing at cutout. 1.2L of pix was applied to this part of the field as part of a variable rate application on the 17 January. The crop then received 2.5L of pix on the 24 January and a further 2L of pix on the 4 February. Aggressive pix management was required to keep crop maturity on track and achieve a final field yield of 11.7 bales per hectare. Out of the 651 bales classed only two bales were G4 micronaire (3.3-3.4). The indeterminate nature of varieties like 748B3F take timely management to induce cutout. Particularly in seasons like the one past, where cool weather delayed squaring, and the assimilate demand of the crop did not act to constrain late January growth.

Overall good management includes timely irrigation scheduling and nutrition supply (including carbohydrate availability) and control of insects when economically viable. For southern growers this will lead to an adequate production higher mic cotton in the middle and lower parts of the plant, that can then blend with the lower micronaire cotton on top of the plant. It is basic maths as the grower attempts to dilute late season bolls that have the potential to bring them a discount. Every season the numbers change.

Growers and consultants continue to strive for the highest yields and quality. Some years in the southern growing region there will be no opportunity to do this late season. Yield will be accumulated within the plant in line with the accumulation of adequate day degrees. Bolls that are grown later in the season will not be as heavy as those created early.

Like all things farming, the factors which will dominate crop production are going to be regionally and even farm specific. It is worthwhile as an industry to share our farming successes, but also reflect on what can be done differently in the future. This is not just a southern problem – this is about our industry’s reputation. Just as importantly, it has the ability to put a few more dollars back into your clients’ pockets.


Long, R.L., Bange, M.P, Delhom, C.D., Church, J.S., and Constable, G.A. (2013, April 9). An assessment of alternative cotton fibre quality attributes and their relationship with yarn strength. Retrieved from CSIRO Publishing: https://www.publish.csiro.au/cp/Fulltext/cp12382

Pubs closed, toilet paper an aspirational item, roadblocks on state borders, social gatherings limited to two people. COVID-19 has turned day-to-day life as we know it on its head – but what about life for an agronomist?

It’s widely agreed that agronomists started social distancing before it had a name – long days in a vehicle mainly communicating with clients by phone. So, for many it’s been business as usual; but with some subtle changes.  

As would be expected, the magnitude of these changes varies a lot depending on the size and nature of the agronomy business.

Damien Erbacher runs Dawson Ag Consulting at Theodore in Central Queensland, a one-man operation. With the continuity of his business heavily dependent on his health and fitness, he’s taken extra steps to ensure good hygiene and social distancing.

“I’ve had a discussion with all my clients about how we communicate with minimal face to face contact and they’ve all been pretty responsive”.

“It hasn’t changed what we do that much – a lot of communication was on the phone and if we need to catch up in the paddock, we exercise social distancing”.

Damien has also been diligent in using sanitised wipes when having external contact such as fuel stations and at the supermarket.     

As expected, larger organisations have also instigated strict hygiene and distancing measures across their teams.

Ben Dawson is an agronomist with B & W Rural at Moree, NSW – a branch with 13 staff, including 6 agronomists.

B & W have taken the approach of minimising contact between staff and between clients.

“We’ve split our merchandise and administration team that work out of our Moree office in two – so one team works one week and the other team the next so if we did have an infection the whole team is not at risk”.

“Our agronomists have based themselves from home so they’re not going into the branch at all”.

On-farm, Ben said most of the work is business as usual with most communication done by phone but avoiding people travelling together in vehicles.

While everything keeps functioning adequately Ben concedes he misses the face-to face contact with colleagues and clients.

“It’s useful being in the office and talking to the merchandise guys and other agronomists about what’s going on and a lot of decisions are made on farm around a kitchen table or in the front seat of a ute with a farmer”.

Amongst the challenges have been new opportunities utilising new communication channels.

The COVID-19 crowd rules saw a rapid end to the popular breakfast meetings B & W Rural held for their clients – an opportunity to discuss what’s happening around the district and new products amongst other things.

Not deterred, they started using the Zoom platform – streaming the meetings live and then having them available to watch later.

Ben was amazed with the response with over 200 farmers taking part in their meetings across several branches.

“We had some farmers on their computer, some streaming on their phones while they were driving around. Going forward, we’ll probably still stream the meetings on Zoom when we can get back to face to face as a lot of people find it convenient.”

Keeping clear channels of communication functioning is a bigger challenge than most for the team at Michael Castor and Associates (MCA). Michael’s team is comprised of 16 agronomists over three offices, and services clients from Belatta NSW to Dulacca QLD and therefore straddles the (closed) state border.

MCA Agronomist Tim Richards said while the restrictions imposed by the virus hampered many aspects of their operation – it had also fast-tracked some innovations in communication their team had been seeking to implement anyway. 

Tim said their team was utilising the Zoom video-conferencing facility heavily for communication both within their team and with clients.

“We’ve shut down our offices with everyone working from home so Zoom meetings have replaced or normal Monday morning staff meetings around the coffee table in the office.”

“On farm we’re aiming for less face-to-face contact with clients so we’re utilising Zoom there also – allowing us to have a discussion but also screen-share spreadsheets so we’re looking at the same thing.”

“This technology was something we’d hoped to use more anyway, and the restrictions have sped it up – made it happen.”

Tim said the biggest challenge of the COVID-19 restrictions has been training young agronomists.

“While the young agronomists are the most tech-savvy, you can’t replace the time spent in the paddock, over a beat-sheet or in the front of a ute with an experienced agronomist”.

So, when the restrictions are finished, pubs are open and toilet paper freely available – will the lives of agronomists return to normal also?

Certainly, the way consultants and their clients have embraced technology out of necessity during COVID-19 has clearly broken down some psychological barriers to adoption. It has also given us the opportunity to experiment and consider how it might enhance our service delivery in the future and some changes might be with us to stay.

Most agree however, that technology will never replace showing a young agronomist a rarely-seen leaf disease, a counter-meal catch-up on a wet day, a face-to-face conversation,  walk through a crop or a cuppa at the kitchen table with our clients.

Anyone working within, or on the fringes of the Australian Cotton industry over the past twelve or so months would be forgiven for feeling just a little battle weary. The combined impacts of drought, bushfires, and battles over water have brought the industry and its players under increased public scrutiny.

While it is easy to dismiss many of these opinions as coming from ill-informed keyboard warriors and unbalanced and unfair journalists, the pressure remains quite squarely with us as an industry. We must proactively work towards rebuilding the battered public image of the cotton industry and validating our social license to farm.

This will be a slow process, but it begins with each of us continuing to display professionalism and best practice in our everyday work.  Few of our critics would be aware of the level of study, professional development and on ground research that backs up the decision making of this industry daily. Little do they know approximately 80% of growers are involved in the Australian Best Management Practice programme myBMP®. (Cotton Australia, 2019) demonstrating a huge commitment to ongoing improvement of its farming and natural resource systems.

But what of the researchers, industry professionals and consultants – the support crew?

For many reasons over the years, the suggestion of compulsory accreditation of Agricultural professionals, has caused division and anxiety.  There have been concerns regarding overregulation, red tape, extra cost burdens to small business operators and lack of recognition of prior learning and hard-earned experience.

While it is easy to list the drawbacks, such an accreditation could form part of the key to revalidating our credibility. Additionally, the lessons learned in other sectors such as banking and finance should lend a warning to those of us providing advice regarding the management of valuable ‘investments’ of our farming clients.

For many years, CCA has offered its own recognition of members who provide annual evidence of their annual upskilling.  These members have been promoted by the organisation as professional, are entitled to use their accreditation as part of the marketing and branding. This acknowledgement is available solely to members of CCA and is mirrored in many associated professional groups including the Soil Society of Australia’s Certified Practising Soil Scientist (CPSS) and AgSafe®. 2

In November 2018, a long awaited and overarching “whole of industry” accreditation was launched by the Ag Institute of Australia (AIA).  Rather than duplicating existing programs, candidates are offered the opportunity to build on their existing accreditation, through the Chartered Practicing Agriculturist (CPAg) scheme. The scheme enables participants to track their ongoing professional development experiences and activities including research, ongoing study and extension activities. AIA has allocated a CPD value to many of these activities however organisations are welcome to submit events and activities for assessment of their continuing professional development point (CPD) value. Practicitioners who achieve CPAg statues are able to use the post nominals CPAg after their name and the logo in marketing materials.

Taking the program to a completely different level, the AIA’s Chartered Agriculturalist scheme (CAg) provides an opportunity for recognition of professionals at a more advanced stage of their career. Successful candidates are recognised for their leadership, commitment to professionalism, accountability and ethical practices and their demonstrated their skills and competencies. Like the CPAg, successful candidates can use their credentials and the associated post nominals and logo as part of their communications and promotion.

CAg accreditation is by application only and requires membership of either AIA or another professional organisation such as the Agronomy Society of Australia or Crop Consultants Australia. There are costs involved in applying for and retaining accreditation however the process of application has been described by CCA participants as the ‘equivalent of filling in a detailed job application.’

CCA Director and long-term member David Kelly is an Agronomist with MacIntyre Independent Agronomists based in Goondiwindi. David recently obtained his CAg accreditation and was happy to share his thoughts on the process.

David feels that the accreditation gave him the opportunity to gain recognition for the professional development in which he had invested so much personally and monetarily. He also believes that it brings a point of difference to his business. In the future he is hopeful it will give him the ability to take on more diversified work that might require such accreditation as either part of the due diligence of the client, or as a prerequisite to the role.

‘It also gives you the incentive to push on with ongoing professional development to retain the accreditation in the future’, he said.

Despite the business advantages that the CAg scheme bring to David, he is keen to encourage anyone who might be interested in accreditation to ‘give it a go.’

“It would be great to see more members of the industry get involved to build the strength and recognition of the programme,” he said.

“It is vital that we continue as an industry to build our reputation for professionalism and accountability. We need to be an industry in which the wider community can have confidence.”

For more information on the schemes visit www.aginstitute.com.au

Cotton Australia. (2019, December 4). Better Cotton Initiave boss applauds Australian Industry – Media Release. Retrieved from Cotton Australia: Cottonaustralia.com.au

There is a new threat out there in the paddock. It is not soil borne, transmitted by insects nor harboured in trash. It cannot be foliar treated, spot sprayed nor eradicated by breeding of resistant varieties. Sadly though, it is prevalent in our industry. It is called complacency. 

Sadly, despite the international warnings and ever growing on shore issues with herbicide resistance, it would appear that in some quarters, the message is just not getting through.  Perhaps we are all just getting tired of hearing about it, or perhaps believe that it is only a problem in other cropping industries and areas but not ours. The bottom line is that resistance development is a natural process in plants, and we are always going to be confronted with this issue in varying degrees.

As scientists – and that is what we are and are qualified in, we tend to put our hope in the next silver bullet. But what if the ‘silver bullet’ is not out there? What if the ‘silver bullet’ does not come in the form of a chemical application that will fit perfectly into our current farming practices?

We have had our silver bullet in our industry that revolutionised the way that we farm. It is called glyphosate. This product, developed originally as an industrial descaler, has enabled us to move away from continuous cultivation and in the age of Roundup Ready® cotton, control weeds at various times of crop development. Now the future of this product from both an availability and efficacy perspective is in doubt.

The cloud that hangs over its commercial availability can be debated long and hard. The recent experiences of Australia’s live export trade have taught us that decisions in the name of the ‘greater good’ can and will be made at the stroke of a pen. Without setting off alarm bells, it is possible that our industry may need to put a Plan B in action – and quickly. This of course is all based on speculation, media attention and the outcomes of domestic court cases. The efficacy discussion however is a different ballgame. Herbicide resistance in our major weeds including those found in northern growing regions is real. It is already with us, and is calling for the Plan B.

The Western Australian Herbicide Resistance Initiative (WAHRI) was launched in 1998 as part of a GRDC initiative in response to the emergence of herbicide resistance in the State’s cropping systems. In 2009, following a recognition that herbicide resistance was not limited to one state and that a national approach was required, the organisation changed its name to the Australian Herbicide Resistance Initiative. The group focuses upon “research, development and extension /communications (RDE) of herbicide resistance and its management for profitable and sustainable cropping systems in the Australian grains industry.” (Beckie, 2019)  It is perhaps the nature of the development of the organisation, and its base in the grains industry, which has led to some apathy within the cotton fraternity that this is ‘not our problem.’

Much of the work and recommendations of AHRI and their industry partner WeedSmart are highly transferable to our own industry and their website and publications are a valuable resource in terms of farming options.  (They are also well worth following on social media.)  CCA member and AHRI Northern Weeds and Crops Extension Agronomist Paul McIntosh said that the message though is really a simple one.

“Whatever you do – Stop the seed set.

“If you stop an annual plant from going to seed you will never have Herbicide Resistance,” says Paul.

Weedsmart, are currently promoting their ‘Big 6’ approach to wise crop weed management where they recommend additional measures such as rotation of crops and pastures and mixing and rotating (full rate) herbicides.

Just as glyphosate has shaped our farming systems, so too will the next wave of mechanical and management options that we will need to incorporate in our future integrated weed management practices. For now, it is very much a ‘watch this space’ event, but upcoming developments such as instant resistance testing options, robotics and even new herbicides based on microbial action are already not far from commercial reality.

Our role as advisors and growers is to ensure that we play an active role in halting the spread of HR. This is everyone’s’ business and there is no longer any room for complacency.

Visit www.weedsmart.org.au and www.ahri.uwa.edu.au & www.cropconsultants.com.au for information on membership and professional development opportunities.

Beckie, H. e. (2019, June). Australian Herbicide Resistance Initiative (AHRI)  celebrates is 20th Anniversary. Outlooks on Pest Management, 120-121. Retrieved from University of Western Australia: https://ahri.uwa.edu.au/

A great frustration for agronomists and growers alike are the crop disorders which we’re powerless to control.

Verticillium Wilt is one such problem.

Crop Consultant Australia’s survey data from the 2017-18 revealed a quarter of agronomists felt Verticillium Wilt has resulted in $50 per hectare reduction in profit through either increased cost of production or reduced yield.

NSW DPI disease surveys have shown this disease incidence increased rapidly through the mid 1980’s but then decreased and plateaued until about 2010 – an effect of more resistance varieties, particularly Sicala V2.

Incidence has increased again from 2010 and while this incidence (the number of fields where the disease is present), is not as high as Black Root Rot and Fusarium in these surveys, the level of crop loss in the areas where is does occur is arguably greater that either of these diseases.

Unfortunately, the disease seems well adapted to high yielding cotton production systems.

  • High nitrogen input exacerbates the disease under all irrigation systems. It’s a hard call for anyone to significantly reduce nitrogen inputs and risk yield loss from deficiency.
  • Low-deficit irrigation practices, used to drive high yields exacerbates the disease.
  • The overhead irrigation systems that many growers have installed in recent years for improved water use efficiency also seem to increase vulnerability. The more surface-dominant crop root systems place the plant is the zone where there is highest pathogen levels. Even with very conservative cotton rotations, such as Cotton to Wheat, several pivots throughout NSW have needed to be pulled out of cotton entirely due to the impact of the disease.
  • Back-to-back cotton increases the pathogen levels in the soil. In years of good allocation, this creates a big problem for ‘land-poor’ farms.

Historically, plant breeding has formed the basis of integrated disease management strategies in cotton.  Bacterial Blight was a major problem to the industry in its infancy but dwindled to insignificance in the late 1980’s- early 1990’s with the introduction of resistant varieties.

Fusarium Wilt shot to prominence in the mid-1990’s and rendered many fields, particularly on the Darling Downs, unsuitable for cotton. Higher F-rank varieties now mean this disease is manageable.

For breeders, Verticillium wilt is proving a bigger challenge.

CSIRO Cotton Breeding Lead, Dr Warwick Stiller says by world standards our current varieties have high levels of Verticillium Wilt resistance but unfortunately, that doesn’t help those growers that are significantly impacted by the disease.

Dr Stiller contends the reasons Verticillium Wilt has proved to more difficult foe than Fusarium Wilt are because it is far more environmentally influenced than Fusarium, unlike Fusarium there are different isolates and VCGs of Verticillium that have a different host plant response and field sites for screening this disease are generally not as uniform or reliable.

“Importantly also, there are no commercial varieties around the world that have significantly better resistance than the current Australian varieties.

“All of these things go together to make breeding for resistance very challenging.

“We are working on developing germplasm that has improved resistance, but unfortunately there won’t be a breeding solution for those bad fields in the near future.

Dr Stiller expects molecular techniques will assist in the future, however, these techniques can’t improve resistance by themselves.

“These techniques only track what we have. Until we develop germplasm with increased resistance, molecular techniques have no value”, he said.

Frustrating again, varietal resistance to Verticillium wilt is temperature sensitive – so varieties with even a high V-rank will succumb to disease when average temperatures drop to 20-22 degrees Celsius or below.

What this means for those in the field is that you could have done everything right – planted a high V-rank variety, avoided excessive N levels, used a good rotation avoided over-watering – and one cool period in December to February could see significant areas defoliate or die.

Clearly this will be another problem we need to research our way out of but in the meantime, for those in the field, any weather forecast for a cold change in December – February will send an extra shiver up their spine.

As we become overwhelmed with new forms of farm data generated by all sorts of technologies, the value of foundation and trend data collected for the cotton industry since the 1980s cannot be overlooked.

Crop Consultants Australia (CCA) has been coordinating the collection of survey data of its practicing members across the key cotton growing regions of Australia since 1982.  CCA started surveying its members in response to a need for reliable product usage records to provide indicators of usage trends.  

CCA continues to coordinate annual qualitative and quantitative surveys for the Australian cotton industry with funding provided by the Cotton Research and Development Corporation (CRDC).

The survey data plays an important role in informing the cotton industry, wider supply chain, the community and government of practice change within the sector, helping the industry to better tell its story.

What might be less known, is that the quantitative data is analysed and published in a report available publicly on the CRDC website.  A very broad range of topics are covered in the survey from staffing and information requirements to every aspect of producing and managing a cotton crop (soils, pests, weeds, fertiliser, technology and water). The quantitative survey consistently represents 50 percent of cotton growing areas and usually achieves over 70 percent coverage.

Additionally, the full set of quantitative survey data is available for purchase and custom analysis can be provided by the CCA project manager.  The quantitative survey collects full seasonal agronomic data relating product usage applied on a particular date, over specified hectares applying to seed, seed dressings, herbicides, insecticides, target pests, plant growth regulators and harvest aids.

CCA aims for data coverage of over 50 percent of Australia’s key cotton producing area.  This data provides a strong indication of products (type and quantity) used to produce a cotton crop each season. Historical data is available for sale and the most recent season data is available from October each year.

Even in our driest of times, CCA is committed to collecting what data is available. It is sometimes these years that tell us more than a ‘good’ year about what is going on in the field.

CCA acknowledges the contribution that consultants make towards building the bigger data picture for the cotton industry. Agworld has been an invaluable partner to the project, enabling client data to be contributed, with their permission, and helping build the overall confidence in the accuracy and quality of the data.  It is hoped that other data management service providers will support the survey project and partner with CCA to enable their clients to also participate.    

Mother Nature has a strong record for reminding us who is boss – particularly when it comes to pest management.

The Integrated Pest Management (IPM) practices for cotton have evolved over time as new technologies become available. Essentially, they revolve around growing the crop in unison with the surrounding environment rather than against it.

Our evolving IPM strategy is published in the annual Cotton Pest Management Guide and its main pillars are…

  • Avoiding the pests from the start through good farm hygiene and consideration of the cropping sequence.
  • Using dynamic insect control thresholds which consider crop health, plant damage, pest number and mix and predator / parasite activity.
  • Diligent and regular monitoring of the above.
  • Doing everything possible to preserve predators and parasites including insecticide use minimisation and predator / parasite friendly selection and including the controlled release of predators where practical.

In recent years we have had a couple of strong reminders of the consequences when deviating from good IPM.

Firstly, is the emergence of two pests which require a lot more than an insecticide armoury to manage them – Silverleaf Whitefly and Solenopsis Mealybug.

Both of these insects, either through natural protection or metabolic changes are able to resist insecticides and tend to be the ‘last bug standing’ after a spray. Hence, the explosions of the populations of these two species often follow heavy broad-spectrum insecticide use.

For instance, Silverleaf Whitefly achieved district-wide outbreak status on several occasions including Central Queensland in 2002 and Gwydir Valley in 2016. In both instances, the problem further deteriorated when people tried to spray their way out – only to destroy beneficial insect populations.

These outbreaks proved to be hard lessons for industry and subsequent seasons have seen an improvement in whitefly management with better insect sampling and improved product selection and timing. This was further assisted with new information from Jamie Hopkinson and his team at QDAF, ranking the impact of various mirid controlling insecticides on Whitefly parasites. Additionally, Jamie Hopkinson’s team is educating consultants on the importance of timely parasite identification and quantification whitefly nymph control. This information proved very popular at the CCA Narrabri Seminar in June 2018 and has been a popular topic of discussion since that event.

The Solenopsis Mealybug, while not as prone to the area-wide outbreaks as Silverleaf Whitefly, has proven very destructive in isolated areas. QDAF Entomologist Paul Grundy has been one of the first people on the scene of many outbreaks of this emerging pest. In almost all cases he has observed a significant breakdown in one or more components of good IPM – including poor farm hygiene or heavy early – season use of broad spectrum insecticides. Paul also spoke about this at CCA’s Regional Workshop Series.

A second recent reminder about the consequences of cutting corners on IPM comes via miticide resistance monitoring by Dr Grant Herron and his team of entomologists at NSW DPI. Their data shows increasing levels of resistance in Two-Spotted Spider Mite to the miticide Abamectin to levels where control will be compromised. Resistance was first reported in 2007 and by 2016-17 season, more that 80 percent of populations surveyed were resistant to this product with some comprising nearly 100 percent resistant individuals.

Much of the blame for this increase in resistance is being pinned on the prophylactic use of Abamectin – ironically the practice of systematically adding the miticide to other insecticide sprays to reduce the likelihood flaring mites.

This however, is just one more lesson in what Mother Nature has dealt to us before. Those new to the industry will not know that the older organophosphates dimethoate and omethoate were reliable miticides against Two-Spotted Spider Mite until resistance developed rapidly in the 1980’s rendering them useless against this pest. They were replaced by newer organophosphates monocrotophos and profenofos which too, stopped working by the early 1990’s. The synthetic pyrethroid bifenthrin was then used throughout the mid 1990’s but it too now has significant resistance and no longer works reliably.

It highlights that our insecticide options need to be used wisely.

These examples show that for “good” IPM to happen successfully, there needs to be a strong and trusting working relationship between the person making the recommendations, whether that be a consulting or on-farm agronomist and the person who is paying the bills.

Our role as agronomists is to accurately collect all of the relevant field information and use that to provide informed discussion with the crop owner so the best IPM compatible decisions can be made.

Crops Consultants Australia has put a lot of resources into building an IPM knowledge bank via our series of winter Workshops where the industry’s leading entomologists have given detailed presentations of their recent work. Combined with the experience within our membership, whose knowledge extends way past these lessons dealt, and the network that links us all, we aim to ensure that our members and the people that they service are well equipped to cope with, or even better avoid, our next lesson from Mother Nature.