There are many ways to assess plant health and the nutrient status of your crop. For example:

• Tissue testing, carried out by a lab, measures the total concentration of nutrients that have accumulated in a plant’s leaf tissue over time, providing a snapshot of overall nutrient status.
• Sap testing, also carried out by a lab, analyses the sap from freshly collected leaves to assess the nutrients currently circulating and available for immediate use, offering a more real-time view of plant health. It can be helpful for making timely fertiliser decisions during the growing season.
• Brix, measured using a hand-held refractometer, reflects the concentration of sugars and other dissolved solids in plant sap and is often used as a broad indicator of photosynthetic activity and plant function. In practice, some advisers suggest that grain crops with Brix readings above around 12 may be associated with better plant function. Lower readings can indicate stress or limitations in nutrition or biological activity, though interpretation varies and context is important.
• Sap pH, measured by a lab or with a handheld meter, reflects the acidity or alkalinity of the plant sap, signaling nutrient imbalances or stress. Some farmers use practitioner frameworks attributed to Bruce Tainio to interpret plant sap pH as a prompt to investigate plant nutritional balance more closely.⁸N Kinsey and C Walters Jr., Hands-On Agronomy, Acres U.S.A., 2005.In this framework, sap pH above around 6.4 is associated with increased vulnerability to insect pressure and potential imbalances in nitrogen, phosphorus and sulfur, while sap pH below around 6.4 is associated with increased disease susceptibility and potential imbalances in calcium, magnesium, potassium and sodium.⁹J Kempf, ‘Sap pH as a susceptibility indicator’, John Kempf (website), 2019, https://johnkempf.com/sap-ph-as-a-susceptibility-indicator/. However, nutrient-pH-disease interactions are highly complex and cannot be generalised across all plant species. More research is needed to establish precise relationships between specific pH levels and plant vulnerability.

When we look at plant nutrition and building resilience, we need to look at the 17 essential nutrients for plant growth. ¹⁰RL Mahler, ‘General Overview of Nutrition for Field and Container Crops.’ 2004 A lack of any one of them can increase vulnerability to pests and disease. These nutrients include: 

• Macronutrients: Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S), Carbon (C), Hydrogen (H), Oxygen (O)
• Micronutrients: Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl), Nickel (Ni).

In addition to these essential nutrients, many plants also benefit from adequate silicon (Si), cobalt (Co), selenium (Se) and sodium (Na).¹¹M Nunes da Silva et al., ‘Non-Essential Elements and Their Role in Sustainable Agriculture’, Agronomy 2022, 12 (888), https://doi.org/10.3390/agronomy12040888. Each of the 17+ nutrients plays a different role. For example, some nutrients contribute to cell wall strength and others contribute to detoxification and metabolism. The following table outlines several nutrients and their role in building plant health and resilience.

Trace elements such as zinc, copper, manganese and silicon play key roles in supporting the enzymes involved in producing defence compounds, like phenolics, flavonoids, terpenes and tannins. These are part of a plant’s secondary metabolism, helping deter pests and suppress pathogens, and the plant’s ability to make them is influenced by nutrition and growing conditions.¹²H Marschner, Marschner’s mineral nutrition of higher plants, 3rd edn (Academic Press, 2012)

Nutrients can be delivered in several ways: as seed treatments, liquid inject at sowing, granular fertilisers or foliar sprays. Foliar applications are becoming an increasingly popular way to fine tune nutrition during the season, especially when weather or soil conditions limit uptake from the root zone. They can be used to correct micronutrient deficiencies, support key crop stages or supply nutrients in small but targeted amounts.

Nitrogen is essential for crop growth, but too much, especially in synthetic form, can make plants more vulnerable to pests and disease.¹⁴J Angus and P Grace, ‘Nitrogen balance and efficiency in Australian cropping systems’, Soil Research, 2017, 55(6), 435–450. When there is more nitrogen than the plant can use, it often ends up as free nitrates or ammonium in the plant sap, which attract some pests, such as aphids.¹⁵MA Aqueel and SR Leather, ‘Effect of nitrogen fertilizer on the growth and survival of Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Homoptera: Aphididae) on different wheat cultivars, Crop Protection, 2011, 30(2), 216–221. doi:10.1016/j.cropro.2010.09.013. High nitrogen fertiliser use can also promote lush, dense leaf growth, creating a more humid microclimate within the canopy, which favours fungal pathogens like powdery mildew and stripe rust.¹⁶ Luo et al., ‘Effects of Nitrogen and Intercropping on the Occurrence of Wheat Powdery Mildew and Stripe Rust and the Relationship With Crop Yield’, Frontiers in Plant Science, 2021, 12: 637393, https://doi.org/10.3389/fpls.2021.637393. The aim is to make sure the nitrogen applied is actually being converted into complete proteins. To do that, a crop needs a suite of supporting nutrients, especially sulphur, magnesium, molybdenum, boron and cobalt.¹⁷MJ Bell and PW Moody, Soil and Plant Nutrition Management for Grain Crops, (Grains Research and Development Corporation, 2021). Including legumes in your rotation can also help supply nitrogen in a slower, more biologically available form. Sap tests or tissue tests can help check what’s really going on in the plant, and apply only what is needed. 

While easier said than done, providing a low stress environment for your crop is going to improve plant resilience. Soil compaction, low soil fertility, drought, flood or temperature extremes can significantly increase vulnerability to pests and disease.¹⁸P Pandey, V Irulappan, MV Bagavathiannan and M Senthil-Kumar, ‘Impact of combined abiotic and biotic stresses on plant growth and avenues for crop improvement by exploiting physio-morphological traits’, Frontiers in Plant Science, vol. 8, 2017, article 537, pp. 1–14, https://doi.org/10.3389/fpls.2017.00537. Stressed plants can show disrupted hormone signalling, lower energy reserves and reduced immune responses,¹⁹D Nguyen, I Rieu, C Mariani and NM van Dam, ‘How plants handle multiple stresses: hormonal interactions underlying responses to abiotic stress and insect herbivory’, Plant Molecular Biology, vol. 91, no. 6, 2016, pp. 727–740, doi:10.1007/s11103-016-0481-8. making them more attractive to insects and more susceptible to infection. Practices that reduce stress include timely sowing, good seed-soil contact, balanced soil fertility and avoiding overuse of synthetic nitrogen.²⁰Tripathi et al., ‘Plant mineral nutrition and disease resistance’.
Stress can also be reduced by improving soil structure and biology, which helps maintain steady water and nutrient availability.

Monitoring is one of the most powerful tools to allow farmers to move from reactive management of pests and disease to more strategic management. Regular crop inspections using tools like beat sheets, sticky traps, visual scouting and weather-based disease forecasts allow farmers to detect early signs of pest or pathogen pressure and assess thresholds before taking action. Simple photo diaries or pest monitoring sheets can help track pressure over time, spot patterns and support decisions. 

Effective monitoring also means understanding pest life cycles, beneficial insect activity and how environmental conditions (like humidity, rainfall or canopy density) influence disease development. This supports timely, targeted responses, often starting with biological or cultural options, and reduces unnecessary chemical use that can disrupt ecological function and lead to resistance. In resilient systems, monitoring is not just a check-up, but an adaptive learning process that builds understanding of pest dynamics over time.

For help with identification and understanding the life cycle of potential pests, Cesar Australia’s PestNotes resource has technical sheets for over 50 agricultural invertebrate pests. 

While forecasting tools and thresholds are helpful, they’re often based on high input, monoculture systems and may not fully account for the dynamics of diverse or biologically active systems. If you have been fostering ecological diversity and have observed increases in insect biodiversity and populations of beneficial species, pest populations may respond differently as a result of improved ecosystem stability and resilience. Use these tools as guides alongside your own observations and local knowledge, not as fixed rules. 

Spray selectivity and timing

What you spray, when you spray and how selective it is can make a big difference to reducing the negative impacts of pesticide use. Broad-spectrum insecticides and fungicides often knock out beneficial species like predators, parasitoids or microbes, making the system susceptible to future pest problems. Where possible, choose more selective options and avoid routine spraying.

Timing is just as important as product choice. Spraying at the wrong crop stage or under poor conditions can reduce efficacy and increase risk. Targeting vulnerable pest life stages (e.g. early instars) and following label rates and re-entry periods also helps slow resistance development. Generally, cooler temperatures and higher humidity improves spray performance, and it’s best practice to avoid the heat of the day – early morning is ideal.

Targeted chemistry to minimise collateral damage

If pest or disease levels exceed economic thresholds, where the expected crop loss outweighs the financial and ecological cost of spraying, you may want to consider an intervention. Choose products with novel modes of action, indicated by their IRAC (Insecticide Resistance Action Committee) or FRAC (Fungicide Resistance Action Committee) group numbers on the label or safety data sheet, as these tend to be more targeted and less disruptive to beneficial insects and soil biology. In contrast, broad spectrum chemistries can wipe out natural enemies,²²F Sánchez-Bayo, ‘Indirect effect of pesticides on insects and other arthropods’, Toxics, vol. 9, no. 8, 2021, article 177, doi:10.3390/toxics9080177 leading to pest resurgence and resistance over time.²³JD Dutcher, ‘A review of resurgence and replacement causing pest outbreaks in IPM’, in Integrated management of plant pests and diseases, vol. 1, Springer, [year], pp. 27–43. Always review label guidance for mode of action (MoA), resistance group and environmental persistence. For example, IRAC recommends not using products from the same MoA group in succession without a break to prevent resistance. 

Improve efficiency

Insecticides and fungicides can be made more effective and less damaging when used strategically. Buffering with fulvic acids, applying biostimulants or biological food sources, and following up with targeted nutrition can support plant defence responses and microbial recovery from the indirect impacts of pesticides. The timing of application, including the crop growth stage, pest life cycle and weather conditions, plays a key role in whether an input is effective or wasted. Following label directions and applying products at the right time also help reduce the risk of resistance. Together, these practices not only improve efficacy but may reduce long-term inputs and help preserve beneficial organisms.²⁴DJ Ashworth et al., ‘Impact of biostimulants and adjuvants on pesticide efficacy and soil microbial activity’, Pest Management Science, vol. 74, no. 11, 2018, pp. 2540–2548, doi:10.1002/ps.5068
A Gupta et al., ‘Biostimulants for sustainable crop production: current status and future perspectives’, Plant and Soil, vol. 455, 2020, pp. 1–34.
RAC Jones et al., Managing fungicide and insecticide resistance in Australian grains, Grains Research and Development Corporation, 2022, accessed 12 February 2026, https://grdc.com.au/resources-and-publications/all-publications/publications/2022/managing-fungicide-and-insecticide-resistance-in-australian-grains

Broad spectrum insecticides, miticides and fungicides can disrupt natural predator-prey balances and trigger secondary pest outbreaks, undermining long-term system stability. Stepping away from calendar-based or preventative use of insecticides and fungicides and instead making decisions based on pest thresholds, monitoring data, crop stage and observed beneficial insect activity is important for long term resilience and economic viability.²⁵S Macfadyen, DC Hardie, L Fagan, K Stefanova, KD Perry, HE DeGraaf, J Holloway, H Spafford and PA Umina, ‘Reducing insecticide use in broad-acres grains production: an Australian study’, PLoS ONE, vol. 9, no. 2, 2014, article e89119, doi:10.1371/journal.pone.0089119. Many farmers are finding that cutting out insecticides has had no impact on their yields. By prioritising plant health, using biological supports and intervening in a targeted way only when necessary, it is possible to maintain crop performance while reducing chemical inputs and improving overall system resilience.

Removal of pesticide seed treatments

Removing commercial insecticide and fungicide seed treatments, especially those containing neonicotinoids,²⁶Neonicotinoids are a group of insecticides, including imidacloprid, clothianidin, thiamethoxam, thiacloprid, acetamiprid and dinotefuran. They are known to have harmful impacts on beneficial insects, especially pollinators like bees. Because of the systemic nature of neonicotinoids, even the pollen from plants grown in soils with neonicotinoid seed treatments can be detrimental. can be a practical and impactful first step towards building a more resilient cropping system. Insecticide treatments on wheat, for example, have been shown to not provide any yield benefit.²⁷Macfadyen et al., ‘Reducing insecticide use in broad-acre grains production’. Neonicotinoids like clothianidin and imidacloprid are highly persistent in soil, with half-lives ranging from 90 days to over 1,000, and have been shown to disrupt beneficial soil microbes and invertebrates (earthworms in particular) essential for nutrient cycling and soil structure.²⁸V Ramasubramanian, ‘Clothianidin in the tropical sugarcane ecosystem: soil persistence and environmental risk assessment under different organic manuring’, Bulletin of Environmental Contamination and Toxicology, vol. 107, no. 6, 2021, pp. 1084–1089, https://doi.org/10.1007/s00128-021-03169-9 Despite their widespread use, multiple field studies in broadacre cropping systems show that insecticidal seed treatments often provide little to no yield benefit, particularly in low pest-pressure conditions.²⁹Macfadyen et al., ‘Reducing insecticide use in broad-acre grains production’. Substituting with biological seed treatments such as microbial inoculants or biostimulants, can enhance root development, nutrient uptake, and early plant vigour, laying the foundation for more resilient, self-reliant crops.³⁰JR Lamichhane, DC Corrales and E Soltani, ‘Biological seed treatments promote crop establishment and yield: a global meta-analysis’, Agronomy for Sustainable Development, vol. 42, 2022, article 55, https://doi.org/10.1007/s13593-022-00761-z See our Biological Seed Treatment Practice Guide for more.

Beneficial insects

Supporting populations of beneficial insects such as ladybirds, lacewings, parasitoid wasps, and spiders can significantly contribute to natural pest control and long term pest management. By promoting habitat diversity through flowering strips, diverse vegetation and cover crops, beneficial insects thrive and help regulate pest populations. Farming systems with increased biodiversity and reduced pesticide use tend to experience better control of pest outbreaks.³¹FJJA Bianchi et al., ‘Sustainable pest regulation in agricultural landscapes’, Proceedings of the Royal Society B, vol. 273, 2006, pp. 1715–1727. Specifically, predators like ladybirds and parasitoid wasps play a critical role in managing aphid populations and early stage caterpillars without disrupting broader ecological balance.³²MH Schmidt, A Lauer, T Purtauf, C Thies, M Schaefer and T Tscharntke, ‘Relative importance of predators and parasitoids for cereal aphid control’, Proceedings of the Royal Society B: Biological Sciences, vol. 270, no. 1527, 2003, pp. 1905–1909, https://doi.org/10.1098/rspb.2003.2469
EW Riddick, ‘Identification of conditions for successful aphid control by ladybirds in greenhouses’, Insects, vol. 8, no. 2, 2017, article 38, https://doi.org/10.3390/insects8020038
While the active release of beneficial insects is uncommon in broadacre cropping due to scale and cost, it has been used successfully in other industries, particularly where background insect diversity has been reduced, through the targeted release of eggs or live beneficial insects at key points in the crop cycle.

Biological alternatives

There are some biological options which can offer a safer alternative to broad-spectrum fungicides and insecticides, especially when used proactively as part of an integrated approach. These include beneficial microbes (such as Trichoderma, Bacillus and Beauveria species), biostimulants and entomopathogenic viruses³³Viruses that cause disease in insects. that are parasitic to insects. Rather than aiming to eliminate pests or pathogens, these inputs can enhance the plant’s natural defences, support beneficial microbial communities and help suppress pest populations. They are most effective when combined with good nutrition, soil health and monitoring, and are increasingly being adopted by Australian growers seeking to build system resilience and reduce chemical reliance.

Choosing resilient varieties is a powerful strategy to reduce pest and disease pressure across a range of cropping systems. Selecting cultivars with known resistance or tolerance to regionally significant threats, such as rusts in wheat, blackleg in canola and root lesion nematodes in cereals and pulses, can substantially reduce the need for chemical inputs. Beyond resistance traits, choosing varieties suited to local soils, rainfall patterns and sowing windows helps minimise plant stress, which can reduce vulnerability to both pests and pathogens. Clean, high-quality seed and biological seed treatments help support strong emergence and early resilience.

It is worth noting, however, that some commercial seed lines are bred under high input conditions and may not perform as reliably in biologically managed or low input systems. Where possible, seek out seed suppliers or breeders who are selecting for resilience in diverse or regenerative systems. Saving your own seed is a great way to build in genetic resilience. 

Managing the crop canopy plays a critical role in reducing disease risk and supporting plant resilience. Dense, humid canopies with poor airflow can create ideal conditions for fungal pathogens, especially in pulses like chickpeas and faba beans, where diseases such as ascochyta and botrytis (grey mould) blight thrive under extended leaf wetness. Adjusting row spacing, reducing excessive nitrogen that drives vegetative growth and using varieties with more open architecture can help improve airflow and reduce humidity within the canopy.

Australian research has shown that wide row spacing in chickpeas can significantly lower disease incidence without reducing yield in dry years.³⁴S Pande, KHM Siddique et al., ‘Ascochyta blight of chickpea: biology, pathogenicity and disease management’, Australasian Plant Pathology, vol. 34, 2005, pp. 1–17.
KJ Moore et al., ‘Managing canopy structure and microclimate to reduce Ascochyta in chickpeas’, GRDC Update Papers, Grains Research and Development Corporation, 2016. These practices can be especially effective when combined with inter-row weed management and stubble handling to further influence microclimate. Managing canopy conditions is not about sacrificing vigour, but about balancing growth and structure to support healthy, resilient crops.

Diversity and resilience go hand in hand. Increasing the diversity of crops grown, both across seasons and within paddocks, helps disrupt pest and disease cycles, suppress weeds and support beneficial soil biology. Strategic crop rotation reduces the carryover of host-specific pests and pathogens, while introducing a wider range of root structures and exudates improves nutrient cycling and soil function. 

In-season diversity through intercropping or companion planting can reduce pest pressure by confusing insect pests, attracting beneficials and limiting disease spread within a canopy. Diverse rotations incorporating legumes and break crops can significantly reduce crown rot and root lesion nematodes in cereals.³⁵Grains Research and Development Corporation, Integrated disease management in cereals, 2021.
JP Thompson et al., ‘Rotation crops for managing root-lesion nematodes (Pratylenchus thornei) in the northern grain region’, Australasian Plant Pathology, vol. 48, 2019, pp. 267–276. By diversifying both what is grown and when, farmers create more robust, biologically active systems that are less reliant on chemical inputs for pest and disease control.

Stubble retention in no-till systems has been helpful in protecting soil, conserving moisture and supporting beneficial soil biology, but it can also create challenges by harbouring pests and disease between seasons. Stubble has been known to increase the risk of diseases like crown rot or pests like slaters and earwigs in certain conditions.

Rather than burning or removing stubble, which can harm soil health, farmers can encourage biological breakdown, supporting soil microbes and nutrient cycling while reducing stubble related disease risk. Practices like multispecies cover crops, grazing or applying microbial inoculants and stimulants (e.g. compost extracts) can speed up decomposition, reduce pest habitat and return nutrients to the soil, helping to manage risk while keeping the soil covered and cycling.

Following these 4 soil health principles can help build resilience in a farming system:

• Minimise or optimise disturbance
• Maintain groundcover
• Increase biodiversity
• Support year round living roots.

Adopting a reduced tillage approach, keeping crop residues or cover crops on the surface, planting a diversity of plants, holistically integrating livestock and ensuring there are living roots in the soil year round, can reduce erosion, improve water infiltration, boost nutrient cycling and strengthen soil biology. Stacking these practices can lead to healthier, more resilient crops and reduced reliance on inputs. Practices that build organic matter, reduce disturbance and feed soil biology, such as compost, cover crops and diverse rotations, can also help foster a protective microbial network.³⁷VVS R Gupta et al., ‘Biological suppression of soilborne diseases in Australian grain farming systems’, Soil Research, vol. 58, no. 4, 2020, pp. 331–346.
SR Dangi et al., ‘Microbial communities influence root disease severity and crop productivity’, Applied Soil Ecology, vol. 120, 2017, pp. 111–120.
V Venturi and C Keel, ‘Signaling in the rhizosphere’, Trends in Plant Science, vol. 21, no. 3, 2016, pp. 187–198

Biological stimulants and inputs, like compost extracts, vermicast, microbial inoculants and biostimulants such as kelp or humic acids, can help boost soil life and improve nutrient cycling. By supporting a diverse and active soil microbiome, these products enhance root to soil interactions, making nutrients more available and helping plants build stronger natural defences. Over time, this biological support can improve plant resilience to pests and disease by promoting healthier growth and more robust immune responses.