Featured Crop
By Ryan Orr Queensland Department of Primary Industries senior horticulturist
As sustainability gains momentum in horticulture, the need to include non-chemical methods in pest management has never been more crucial.
In mango orchards, innovative canopy and orchard systems are a potential transformative breakthrough.
These systems not only drive productivity but may also help reduce pest pressure and damage – offering a win-win for growers and the environment.
Until recently, however, much of the focus in orchard management centred on maximising yields, leaving the pest-management potential of canopy design relatively underexplored.
High-density canopy systems: a closer look at pest reduction
Emerging research is shedding light on how high-density canopy designs can influence pest control in mango production. Past studies in other crops like apples, macadamias, and pecans have demonstrated strategic canopy manipulation can mitigate damage from certain pests.
These principles are now being trialled in mango plantations, with promising results in managing mango scale infestations.
Mango scale poses a significant problem for the industry, particularly due to the cosmetic damage it causes to fruit skins, which undermines their market appeal (Figure 1).
Severe infestations are even more damaging, leading to leaf loss and, in some cases, the death of smaller branches. While chemical measures have traditionally been relied upon for tackling this pest, the prospect of using canopy design as a non-chemical solution is gaining traction.
Our study highlights the significant impact of canopy management systems on scale control and fruit quality in mango production.
By comparing high-density narrow hedge and espalier trellis canopy systems with the traditional low-density wide open-vase system (Figure 2), we observed a notable reduction in scale insect populations and associated fruit damage over a five-year period.
Key findings included:
- Reduction in female scale populations: Narrow canopy systems (both hedge and espalier trellis) had significantly fewer female scale insects on foliage compared to the open-vase system.
- Improved fruit quality: In the Calypso mango variety, narrow canopy systems led to:
- A 64–84 per cent reduction in scale damage to fruit.A 58–89 per cent reduction in fruit downgrades caused by scale damage.
These results suggest adopting narrow canopy systems could be a highly effective strategy for pest management and improving fruit quality in mango orchards.
This approach not only reduces pest populations but also minimises economic losses due to downgraded fruit.
The study also highlights two key factors that likely contribute to the reduced scale populations and damage observed in narrower canopy systems.
Narrower canopies create a less suitable microclimate for pest development compared to wider canopies, potentially disrupting the lifecycle of scale insects.
They also allow for better penetration of pesticides into the inner parts of the canopy, where scale insects typically reside, enhancing the effectiveness of pest control measures.
At this stage, the relative contribution of these two factors cannot be separated, and it is likely that both play a role in the observed outcomes.
This underscores the potential for integrated pest management strategies that leverage both physical canopy design and optimised pesticide application.
Based on these findings we suggest adoption of highly productive mango canopy designs will provide additional benefit to farmers and consumers by improving pest control and potentially reducing pesticide use.
For further details on this research please see the recently published journal article, Narrow, Open Canopy Architecture Enables More Effective Management of Mango Scale, Aulacaspis tubercularis Newstead in Mango Orchards, available at https://doi.org/10.1111/jen.13474.
Where to next?
The next steps in this research are focused on expanding the understanding of how tree canopy management can address broader pest management challenges in mango production.
Findings to date have been achieved by Queensland government researchers with funding from the Australian Centre for International Agricultural Research under the project, “Development of area-wide management approaches for fruit flies in mango for Indonesia, Philippines, Australia and the Asia-Pacific region (HORT/2015/042) and Hort Innovation under the National Tree Crop Intensification Program (AS18000).
Both programs have now completed but this work is continuing under the Fresh and Secure Trade Alliance (AM22000) to understand the effectiveness of tree canopy management in reducing pressure and damage from other economically important mango pests, such as fruit fly and mango seed weevil.
In addition, fruit quality outcomes will be observed with less frequent pesticide applications to determine the potential pesticide saving from good canopy design.
Multi-year trials are currently commencing to understand how tree canopies can be designed not just to increase production efficiency but also pest management efficiency, delivering increased productivity and sustainability for growers and consumers.
