Jonathan Garner pushes a pest aside with integrated pest management systems to control pests safely and sustainably.
I hope you had a good winter and this chat provides you with a better understanding of alternative ways to manage pests and disease within your landscape asset. How good would something like this read on your company profile?
‘AAAA Gardens’ policy is to use Integrated Pest Management (IPM) to control pests safely and sustainably. This combines monitoring, biological controls and low-toxicity treatments that protect your garden, family, and the environment’.
Pre-emptive
Integrated Pest Management is a holistic approach to managing pests in the most environmentally friendly way possible. The goal isn’t to eliminate every pest. The aim is to keep major pest outbreaks in check and from causing considerable harm while minimising the risks to staff, public, pets, and the environment.
Essentially, the system flips our approach from being reactive to proactive – by this I mean having measures in place to prevent pest outbreaks rather than having to deal with it once the outbreak occurs.
No nuking needed
If you haven’t set up preventative measures initially, it’s likely you’ll be faced with an outbreak and will need chemicals to eliminate or reduce the pest pressure. After numbers are down, you’d follow up by introducing natural controls such as beneficial insects and improving the cultural practices: correct watering, feeding, and if the pest pressure is continual and opportunities are available, removing and replacing the specimen with the right plant for the right place.
Before we jump into an integrated pest management example, the universal task you need to undertake is getting to know the pest. There’s plenty of information online or in books, but the process basically goes:
1. Identify it
2. Identify the signs of it and what it does
3. Learn about its lifecycle so you can intervene to break the lifecycle. Breaking the cycle puts breeding in check. Less offspring naturally means less ongoing pests in the future
4. Learn about its predators and parasites. It’s quite likely these friends are already managing your pest, and
5. Learn when the critter is at its most vulnerable. If you have to use chemicals, these will be most effective times and require you to use much less product. This is important, as intervening with chemicals often breaks the natural balances by killing off everything where you’ve sprayed. Nuking the area is a quick fix which often ties you to repeating the same process to manage the pest you’re trying to control.
Stepping through the process
Let’s set a scenario of using integrated pest management to manage a common pest: mealybug.
There are numerous species of these soft-bodied insects that thrive throughout Australia. They look like tiny bits of white cotton and often gather in hidden or protected spots on plants – places like leaf
joints, stems, and under leaves. They suck sap from the plant, weakening it over time, and infestations can cause stunted growth, yellowing leaves, leaf drop, and black sooty mould caused by the sticky honeydew they leave behind. They adore plants such as Cordyline, Agapanthus, Clivia and most other
strap-leaved plants where they can feed while staying hidden amongst developing leaves.
Saying this, there’s very few, if any, ornamentals that mealybug won’t feed on.
In areas exposed to the cold, their lifecycles slow down. Now it’s warming, eggs are hatching. In Queensland, and elsewhere in protected areas such as indoors and courtyards, mealybugs are active throughout the year.
Once I’ve got to know the pest and its lifecycle, here are the steps I take using an integrated system…
1. Monitoring
Check the plants often and know what you’re looking at. Check your susceptible plants for signs of trouble. The earlier you catch mealybugs, the easier they are to control.
Look out for:
• White, fluffy or cottony patches on leaves, stems, or fruit
• Clusters of small, slow-moving white insects (adults are about 3mm–4mm long). The young or nymphs are much smaller and have yet to grow the fluffy cotton
• Sticky leaves or stems from their sugary excrements – aka ‘honeydew’
• Ants crawling on the plant as they feed on the honeydew and protect mealy bugs
• Black sooty mould growing on sticky surfaces, and
• Look beneath leaves, spaces around growing tips, or anywhere protected.
If you’re unsure, take a close-up photo and show it to your local nursery or garden centre. You can also check online garden-pest guides, such as those from Agriculture Victoria, NSW DPI, or local gardening websites.
2. Mechanical control
If I notice a small number or an outbreak, I’ll rub them out with my fingers or spray the colony with a
Blasting the colony can displace plenty of them. Interestingly, once they’re on the ground and no longer producing honeydew, the ants and other scavengers will often eat them. Reducing the colony size reduces plant injury and enables predators to clean them up much faster.
For heavy infestations consider pruning back the plant or even replacing it.
3. Biological control (the fun stuff)
Mealybugs have several natural enemies that help control their numbers. Consider buying and releasing plenty of these natural born killers over the warmer months. Trust me, in the right conditions, they work. Ladybeetles (especially the native mealybug hunter Cryptolaemus. Confusingly, the nymphs look much like the mealy bug), Lacewings, parasitic wasps and predatory beetles are good options.
Check out goodbugs.org.au for more information and suppliers.
A quick tip if you’re buying and releasing ladybeetles: invest in beetle bags to keep them close by until they acclimatise. They’ll arrive hungry and spread out fast in search of dinner.
Encouraging these helpful insects is an important part of integrated pest management, and planting nectar-rich plants and flowers tends to encourage and lure beneficials (although this might be tricky within the landscape asset).
Avoid using broad-spectrum insecticides which kill both pests and their predators, and control ants, which protect mealybugs from predators in exchange for honeydew.
To control ants use sticky bands around trunks of trees or shrubs, or place ant baits near the base of infested plants.
4. Organic and low-toxicity sprays
As mentioned earlier, if mechanical and biological controls aren’t enough, try to focus on low-toxicity or organic sprays that are safe for your staff, clients and beneficial insects. Understanding that we’re working within commercial enterprises, organic approaches can be time-consuming and require regular follow ups. If you’re in a residential garden, consider engaging ‘customer participation’ where the client can monitor and treat outbreaks with these sprays.
Some options include:
• Horticultural oils (White Oil or Eco-Oil). These suffocate mealybugs and their eggs. Spray thoroughly on all affected parts, including undersides of leaves. Reapply every seven to 14 days if needed. Avoid
spraying during hot weather (over 30°C)
• Insecticidal soap. It must make contact to work, and needs to be reapplied after rain or as needed
• Azamax (refined neem oil) disrupts feeding and reproduction and acts as a mild repellent. It’s safe for most beneficial insects when used properly. Always read and follow the label instructions and test on a small part of the plant first.
5. Chemical pesticides. The last resort
If all other methods fail and the infestation is severe, consider using chemical insecticides in a strategic approach. Apart from pyrethrum and its synthetic versions, you won’t find anything punchy enough in the big hardware chain.
As most landscape professionals lack chemical certification, I won’t suggest effective chemicals. Those of us who are certified probably know which product to reach for.
If you’re at the garden centre or looking online, look for products that are systemic (absorbed by the plant and kills pests when they feed), and registered for mealybug control in home gardens.
When you are spraying:
• Avoid spraying during flowering or when bees are active
• Apply in the evening or early morning, and
• Follow the label carefully, always wearing protective clothing.
Please remember most chemical sprays will kill beneficial insects and may also lead to pest resistance over time. Use them strategically, sparingly, and in combination with other integrated pest management methods. If you have to use them, learn about the chemical and its residual effect, knock out your pest, and invest in releasing a range of biological control once the residual effect has ended.
Failing to do this will likely result in another pest outbreak.