Fresh Thoughts

Horticulture and Irrigated Agriculture

Welcome

Welcome to the new format and latest edition of Fresh Thoughts, DPIRD's quarterly horticulture newsletter bringing together information and updates on practical research, trials, insect and disease management updates and seasonal insights from across Western Australia (WA). 

Each issue will highlight applied research trials, emerging technologies and on-farm learnings from key horticultural regions, including Carnarvon, Manjimup and the Ord River Irrigation Area. Fresh Thoughts supports informed decision-making by connecting growers, researchers and industry partners and showcasing how research is being translated into practical outcomes. 

At the heart of the Horticulture and Irrigated Agriculture team is a simple belief: Western Australia’s growers play a vital role in nourishing our communities and shaping a vibrant, sustainable future. We work beside industry, listening, learning and co‑designing solutions, to help them navigate challenges, unlock new opportunities and strengthen the state’s capacity to supply the fresh, high‑quality food Western Australians rely on every day. Through research that inspires innovation and builds resilience, we’re helping secure a prosperous horticulture sector, and a dependable food supply. 

 Our team delivers research and trials across WA, from the Kimberley to the South West, working closely with growers and applying data‑driven insights to drive meaningful and practical outcomes. We look forward to highlighting work from each region in future editions. 

 For a clear picture of horticulture’s contribution to WA’s economy and food supply, we invite you to view the Value of Horticulture from Western Australia 2023–24. 

Maximising carrot packout: New national research project underway

Carrot plot for research at Shenton Park.

A new three-year, nationally coordinated research project is underway to help Australian carrot growers improve packout rates and reduce losses caused by defects. Funded by Hort Innovation, the Maximising Carrot Packout project (VG24007) is being led by DPIRD in partnership with South Australian Research and Development Institute (SARDI) and the Queensland Department of Primary Industries.

The project is focused on improving on-farm production, disease management and postharvest handling to increase the proportion of carrots meeting market specifications, which is an issue with significant implications for grower profitability.

The first stage is underway and involves close collaboration with growers through interviews, on-farm monitoring, supply-chain assessments and a literature review to identify key causes of carrot defects and prioritise research needs. This will inform a targeted R&D plan and on-farm trials in later stages, investigating production factors, disease pressures and postharvest storage practices.

An economic assessment will evaluate the cost–benefit of improved management practices, while the final stage will focus on extension and adoption. Growers will have access to practical outputs including demonstrations, workshops, publications, videos and digital resources designed to support real-world uptake of proven practices.

By addressing both production and postharvest challenges, the project aims to deliver practical, economically sound solutions that help growers lift carrot quality, reduce waste and strengthen returns across domestic and export markets

Molecular breeding in the Australian National Apple Breeding Program

Dr Sultan Mia, lead for the molecular breeding problem

DPIRD’s Australian National Apple Breeding Program (ANABP) has more than 50 years of experience developing high-quality apple varieties suited to Australian growing conditions. Successful releases include Cripps Pink (Pink Lady®), Cripps Red (Sundowner®) and ANABP 01 (Bravo™ / Soluna®). As Australia’s only apple breeding program, ANABP combines long-term field evaluation with modern molecular tools to identify superior varieties, a process that typically takes around 20 years from cross to release.

Molecular breeding at ANABP is led by Dr Sultan Mia, who is delivering three externally funded projects that strengthen genetics-enabled apple breeding.

A five-year Hort Innovation–funded project (AS23003) is integrating phenotyping, statistical modelling and whole-genome sequencing to support next-generation orchard performance. Field sampling and first-season phenotyping are now underway at Manjimup, supported by new research staff and PhD students.

Two complementary projects are accelerating breeding efficiency: AS22000, a three-year Hort Innovation project developing low-cost genotyping methods for early selection, and ICHDR1, an ARC-funded project using phenomics and genomics to better understand dormancy, flowering and pollination behaviour. Together, these projects are building faster, more informed pathways to deliver improved apple varieties for the Australian industry.

By using modern genomics and phenotyping tools, DPIRD’s apple breeding program can identify the most promising varieties earlier and with greater confidence. This means future apple varieties are more likely to deliver consistent yields, improved fruit quality, better flowering and pollination performance, and stronger adaptation to local climates. Over time, these advances help growers make more informed planting decisions, reduce risk when investing in new orchards, and remain competitive in both domestic and export markets

Jane Brownlee

Jane has recently joined the team, bringing a diverse background in agricultural research, environmental science, and water management. Her career has led her to work across a wide range of crops, including wheat, barley, canola, chickpeas, pulses, and sugarcane. Jane recently completed her Master of Environmental Science at UWA with a specialisation in Water and Catchments and previously worked with CSIRO. Jane is currently working within the Intensive and Irrigated Plant Systems Team on the Drainage Water Recycling Project.

In her role as a Research Scientist, she is investigating the feasibility of drainage water recycling systems, focusing on water quality, treatment methods, and the environmental and agronomic impacts of using recycled drainage water to support more sustainable and efficient horticultural production.

Outside of work, she enjoys the outdoors through camping in national parks, adventure racing, and hiking.

Practical tips for detection of Polyphagous Shot-Hole Borer (PSHB) in orchard tree species

Polyphagous shot-hole borer (PSHB) is an invasive ambrosia beetle native to Southeast Asia. PSHB bore into the live and dead wood of trees, creating a system of tunnels or galleries. In these galleries, they cultivate a pathogenic Fusarium fungus, which serves as their food source. The Fusarium fungus also blocks the flow of nutrients through the trees’ xylem, causing limb dieback and eventual tree death in the worst cases.

Tree Species

PSHB inhabit a wide range of host trees. The global host list, of all known vulnerable hosts, contains over 600 plant species. Many commercially cultivated fruit tree species are potential hosts (listed alphabetically).

• Citrus sp. (Lemon / Lime / Grapefruit) - Non-reproductive
• Ceratonia siliqua (Carob) - Non-reproductive
• Macadamia integrifolia (Macadamia)
• Malus domestica (Apple) - Reproductive
• Morus alba / nigra (Mulberry) - Reproductive
• Persea americana. (Avocado) - Reproductive
• Pyrus communis / pyrifolia / kawakamii (Pear) – Reproductive / Non-reproductive / non-reproductive, respectively
• Vitis vinifera (Grape) - Non-reproductive

General symptoms of PSHB

Figure 1: Common symptoms of PSHB. (Photo source: DPIRD)

Gumming/Staining/Lesions: Spots of gum and resin protruding from PSHB entry holes. The severity of this symptom is largely dependent on tree species and health.

Dieback: Dieback caused from the PSHB associated Fusarium fungus. Fusarium Dieback will generally start at the outer branches and work its way in towards the tree’s base. This symptom may not be as apparent in new or low-level infestations.

Frass: As the borer push the wood debris out of their galleries, it often takes the shape of the tunnel from which it is extruded, giving it a noodle-like appearance. Frass from PSHB can also take the form of a loose covering of sawdust on the affected branch, as well as collecting around the base of the tree in heavier infestations. Presence of frass can indicate active infestations.

Galleries: Galleries are the cross-section of the system of tunnels PSHB bore into a tree. The walls of the galleries are stained black by the Fusarium fungus. This symptom will become apparent during PSHB-related limb failures, as well as when pruning through an infested area.

Shot Holes: Shot holes are the entry holes caused by PSHB boring into the tree. Shot holes from PSHB measure 1 mm, or the size of a pen tip. A distinguishing feature of PSHB-shotholes, as opposed other wood and bark beetles, is that PSHB shot holes are very consistent in their diameter and their circularity. Many boring species will create shot holes that vary in size or shape across an affected area.

Combination of Symptoms

It is important to note that not all these symptoms will always be apparent in an infested tree. Each species of host tree will have a different host response to an infestation and produce varying degrees of each symptom. Heavy rain and wind also have the potential to wash or blow frass away, as well as make staining less apparent.

Example of infested Avocado trees

Below photos are sourced from Avocado trees confirmed to be laboratory positive for PSHB.

Sugar volcanos: Sugar volcanoes are a symptom very often seen in infested avocado trees. The presence of these formations can obscure shotholes from view. The shotholes may only become apparent after removal of the sugar and the outer layer of bark (Figure 2).

Due to the the colour contrast of sugar volcanoes with the dark bark, this symptom is more easily identified. A good way to start surveillance on an avocado tree is to do a quick visual scan of the whole tree for any of these areas. If one or more are identified, use a chisel or other tool to remove it and the outer layer of bark, looking for ~1 mm sized shot holes.

Figure 2: (Left) Sugar volcano on the bark of an infested avocado. (Right) Shothole is revealed after removal of outer layer of bark and sugar volcano. (Photo source: DPIRD)

To answer your questions and provide more information, two workshops have been confirmed.
Manjimup: 24 February 2026
Bunbury: 4 March 2026
For more details please email PSHB.CBT.Information@dpird.wa.gov.au

Insecticide resistance in cluster caterpillar: what growers need to know

DPIRD will also host a webinar to unpack the results in more detail, explain what they mean for different regions, and discuss strategies to slow resistance development and protect future control options. 

Managing Insecticide Resistance in Cluster Caterpillar 
11 February, 10am, 2026  

This webinar is relevant for commercial growers, agronomists and anyone managing cluster caterpillar in Western Australia.

Smart orchard platform trial supports Narrow Orchard Systems adoption

Potential applications of artificial intelligence and computer vision in vegetable research

Artificial intelligence (AI) and computer vision are changing agriculture in general and horticultural sector in particular through real-time monitoring, pest and disease diagnosis, and automation. They are helping to transform agriculture from traditional, experience-based farming to data-driven, precise cultivation. These technologies optimize water/fertilizer use, weather forecasting, and farm management, leading to increased productivity and reduced production costs. Computer vision identifies diseases through images, while AI analyses data to make smarter farming decisions. These technologies can serve both as research tools for scientists and help farmers make informed decisions in agricultural production.

The potential applications of AI and computer vision in horticulture can be briefly summarised as follows:

• Plant disease and health diagnosis: cameras combined with computer vision algorithms analyse plant leaves, identifying early signs of pests, diseases, or nutrient deficiencies to suggest appropriate treatments.
• Autonomous robots: using AI to recognise crops, automatically harvest ripe produce, weed, or spray pesticides precisely where needed, minimising manual labour.
• Environmental monitoring and management: AI systems combined with the Internet of Things (IoT) analyse soil moisture and weather conditions to optimise irrigation and fertilisation processes, helping to save resources.
• Sorting and quality control of horticultural products: computer vision is applied in production lines to sort products by size, colour, and freshness.
• Forecasting and planning: AI analyses historical data to predict crop yields, optimal planting times, and market prices.

Due to such enormous potential of these technologies, the Carnarvon vegetable research team has begun exploring the application of these technologies in vegetable research and production, using a combination of drone technology and computer vision to develop several applications. The research team has started developing applications such as:

• Tomato disease diagnostic app
• Applications for counting and classifying fruit on tomato and mango trees in the field and for evaluating the growth and early vigour of melon varieties using Green – Blue NDVI and canopy size indicators, which uses a combination of the drone technology and computer vision: View Here

Overall, these technologies help optimise every step in the value chain, reduce the use of pesticides, fertiliser application and irrigation regime for vegetable production. It’s noted that AI does not replace humans but acts as an "assistant," providing information to manage data and operate intelligent systems.

Figure 1: An example of the interface of the Tomato Disease app. This program allows users to input images for disease diagnosis, diagnostic tools, results, a brief description of the disease, and the specific chemicals used to control it.

Annual vegetable variety trials and field days at Carnarvon Research Station

Carnarvon’s hot, semi-arid climate presents significant challenges for vegetable production, including high temperatures, intense radiation, and high pest and disease pressure. These conditions can reduce yield and quality in crops such as tomatoes, capsicums and melons, making variety choice critical for grower success among other approaches.

Since 2015, DPIRD has conducted annual vegetable variety trials at the Carnarvon Research Station to identify varieties best suited to local conditions. Working with Australia’s major commercial vegetable seed companies, new breeding lines and varieties are first screened in observation trials, with the most promising then evaluated in replicated trials at the research station and on growers’ farms. Varieties showing strong yield, quality and resilience are promoted for industry adoption.

In 2025, trials included 55 capsicum, 74 tomato and 124 melon varieties, tested across winter and spring seasons. Field days held in partnership with seed companies gave growers and industry stakeholders the opportunity to view trial results firsthand and compare variety performance under local conditions.
These trials provide independent, locally relevant information to help growers select varieties with the best potential for yield, quality and resilience in Carnarvon conditions, reducing production risk and supporting more profitable cropping decisions.

Below are some photographs of the variety trials and field days in 2025.

The vegetable research team and representatives from the eight commercial seed companies at the melon field day.

The tomato and capsicum field day in August 2025, which was attended by more than 50 farmers, industry stakeholders and visitors.

The melon field day in December 2025, which drew attendance by more than 70 farmers, industry stakeholders, scientists and visitors.

WA Grower Magazine

Important disclaimer 
The Chief Executive Officer of the Department of Primary Industries and Regional Development and the State of Western Australia accept no liability whatsoever by reason of negligence or otherwise arising from the use or release of this information or any part of it. If you have any questions, or require further information please email jennifer.birkhead@dpird.wa.gov.au

Copyright © State of Western Australia (Department of Primary Industries and Regional Development), 2026.