Revitalising sustainability and biosecurity at our Nursery: a new approach to Integrated Pest Management
Case study by Rural Design nursery manager Dani McBride (pictured in the middle above with colleagues Jack Warden and Abby Lomas)
In the world of horticulture, maintaining healthy, thriving plants is the ultimate goal, yet the journey to achieve this can sometimes be fraught with challenges. For us, this reality hit home last year after a devastating crop loss due to chemical pesticide use. This loss forced us to rethink everything—from our pest management practices to our broader sustainability and biosecurity initiatives. Our goal became clear: to adopt a more sustainable, targeted, and proactive approach to pest and disease management that would not only improve plant health but also minimise environmental impact. Today, we're proud to share our journey toward a more effective, sustainable, and environmentally conscious approach to plant care.
The Challenges
Our nursery faces unique challenges that are not commonly addressed in other horticultural sectors. Unlike the more standardised pest management practices used in conventional horticulture crops, there is no established model, or chemical treatment solutions for managing pests and diseases in the wide variety of plants we grow. We cultivate over 200 different New Zealand native plant species, each with its own specific requirements and vulnerabilities. This diversity means we deal with both native and introduced pests and diseases—many of which are not well documented or shared across the industry.
Prior to making changes, our nursery relied on blanket chemical treatments for all plants; a one size fits all model. This resulted in unnecessary chemical use, affecting non-susceptible species, and disrupting beneficial insects and fungi. Additionally, staff knowledge gaps and inconsistent advice on chemical use led to confusion about the best practices for different plant species and pest issues. Without clear action thresholds for when to apply treatments, our pest management was reactive rather than preventative. This lack of strategic focus made it difficult to manage disease resistance and track the effectiveness of treatments over time.
The Solution
To address these challenges, we introduced several key changes to our pest management practices, starting with a thorough risk-ranking process and evolving into a more sustainable, targeted approach.
1. Risk Ranking for Pests and Diseases
The first step in our new strategy was conducting a comprehensive risk ranking for all pests and diseases present in the nursery. This involved evaluating each pest or disease based on a variety of factors, including its rate of reproduction, potential for spread, the number of species impacted, and the type and extent of damage it could cause if left untreated. We also considered potential crop loss and preventative control options, as well as any relevant compliance factors. This risk ranking allowed us to prioritize pest management efforts, focusing on the highest-risk issues and ensuring that resources were used effectively.
2. Targeted Chemical Use
Rather than blanket spraying, we have focused on a more targeted approach. Now, full nursery spray rounds are limited to chemicals that specifically address known pathogens that pose a significant risk to our nursery, such as Pythium and Phytophthora (a result of dam water usage). For foliar fertilizers and systemic insecticides, we implement separate rounds, but only during periods of high pest pressure. More importantly, our focus is on treating susceptible species only. For example, grasses might be treated for foliage/crown rusts, while veronicas might receive treatments for mildew during their risk periods. This focused approach minimizes unnecessary chemical use and reduces the environmental footprint of our operations.
3. Biological Controls and Preventative Measures
One of the most significant changes has been our move toward biological controls. For over six months, we’ve eliminated insecticide use in our hot houses, instead introducing five different biological control agents to manage pests like fungus gnat larvae, aphids, and whiteflies. Alongside these biological controls, we’ve adopted eco-trapping methods as a preventative measure and monitoring tool. These changes have enabled us to manage pest populations more naturally, reducing our reliance on chemicals.
4. Prevention-Focused Mindset
We’ve also shifted from a reactive to a prevention-focused mindset. To support this transition, we’ve provided extensive training to our team on identifying fungal and insect pathogens and using passive monitoring techniques to detect issues early. By empowering staff to recognize early signs of pest and disease problems, we can act proactively to prevent infestations before they escalate.
Where We Are Now
The results of these changes have been positive. The risk ranking process has allowed us to prioritize and focus our pest management efforts on the highest-risk issues, ensuring that we’re using our resources effectively. The electronic record-keeping system helps us track pesticide use and manage resistance. We’ve also significantly reduced our reliance on insecticides, and biological controls and eco-trapping have proven effective in managing pest populations without harming beneficial insects.
Our shift to a prevention-focused approach has contributed to healthier plants and fewer pest-related crop losses. The additional training and improved monitoring techniques have allowed us to detect issues earlier, enabling us to respond more effectively and address problems before they become significant.
While there has been an initial investment in time and training, the results are beginning to show. Not only are we seeing improvements in pest management, but we’re also contributing to more sustainable practices in the horticultural industry.
Looking Ahead
As we continue to refine our practices, we remain committed to sustainability and responsible pest management. Our focus will be on enhancing our biological control programs, exploring new monitoring techniques, and continuing to improve our team’s ability to manage pests proactively. We are optimistic that this shift toward more sustainable and targeted pest management practices will continue to improve both plant health and environmental impact in the long term.