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How to Control Garden Pests with a Balanced Approach

Say goodbye to garden pests the smart way by using natural allies, organic sprays, and targeted treatments.

Pests are a natural part of every garden, but unchecked infestations can quickly damage plants and reduce yields. There is no one-stop miracle cure for your garden woes, no matter what the label says. Using a holistic approach that focuses on combating pests at different stages of the life cycle by blending cultural, biological and, if necessary, chemical controls, is the most effective way to say goodbye to pests.

Leaf-chewers

Cabbage moth & cabbage white butterfly

Cabbage moths and cabbage white butterflies lay eggs on brassicas such as cabbage, broccoli, and kale. The caterpillars of both creatures feed quickly and voraciously, leaving large holes in leaves and often boring into developing heads.

  • Cabbage whiteB butterfly
  • Cabbage white butterfly
  • Bacillus thuringiensis
  • Yates Advanced Garden
    Insect Killer

Solutions

  • Cultural: Inspect plants regularly and remove eggs and caterpillars by hand. Use fine mesh or row covers to prevent moths from laying eggs on vegetables. Add decoy plants around the garden that attract cabbage moth and cabbage white butterfly, such as nasturtium.
  • Biological: Encourage parasitic wasps, birds, and predatory insects to feed on caterpillars.
  • Organic: Apply Bacillus thuringiensis to leaves as a safe and effective biological spray. Neem oil can also deter caterpillars.
  • Chemical: Targeted insecticides may be applied during outbreaks, but avoid spraying when beneficial insects are active.

Codling moth

Codling moth larvae burrow into apples and pears, leaving fruit unpalatable and unmarketable. While the fruit do remain edible, they are a major concern in home orchards.

  • Codling moth damage on apples
  • Adult codling moth
  • Codling moth trap
  • Bacillus thuringiensis
  • Yates Success Ultra

Solutions

  • Cultural: Remove and destroy fallen or infested fruit in autumn. Wrap cardboard bands or hessian sacks around trunks to trap larvae and shake them out every fortnight during the larval period.
  • Biological: Let chickens loose in the orchard to make quick work of coddling moth larvae.
  • Organic: Pheromone traps help monitor moth activity and disrupt mating, however, small birds can become trapped in the sticky tape. Protect pheromone traps with bird-friendly netting, which allows the male moths to continue entering the traps. Apply Bacillus thuringiensis to leaves to lessen the number of caterpillars.
  • Chemical: Apply registered insecticides during egg-laying periods if necessary.

Earwigs

Earwigs are nocturnal insects that feed on tender seedlings, soft fruits, and flower petals, often leaving irregular holes and ragged edges on plants. While they can be beneficial by eating aphids and decaying matter, large populations may cause significant damage.

Solutions

  • Cultural: Trap earwigs by placing rolled-up newspaper, bamboo canes, or upturned pots filled with straw in the garden, then dispose of them each morning. Reduce hiding places by clearing debris and mulch close to vulnerable plants.
  • Biological: Encourage natural predators such as birds, toads, and predatory beetles.
  • Organic: Use oil-and-soy sauce traps sunk into the soil to lure and drown earwigs, or apply diatomaceous earth around plants. Deep Green Permaculture has a detailed recipe and guide on how to set the trap. Pyrethrum sprays can also be used to control earwigs, however, minimise harm to beneficial insects by spraying during late evening, night, or early morning.
  • Chemical: Apply targeted insecticides at soil level if infestations are severe, following label instructions to minimise harm to beneficial insects.

Harlequin beetle

Harlequin beetles feed on leaves and flowers, often causing cosmetic damage but occasionally weakening plants. They are recognisable by their striking black, orange, and red patterns.

Solutions

  • Cultural: Pick beetles off by hand and place them in soapy water, encourage birds to feed on them. Remove plants in the mallow family, as they are attracted to them.
  • Biological: Predatory insects or birds can help keep populations in check.
  • Organic: Neem oil sprays are effective for minor infestations.
  • Chemical: Registered insecticides can be used for severe cases, applied carefully to minimise impact on pollinators.

Katydid

Katydids are green, leaf-like insects that chew on foliage, flowers, and fruit, often causing ragged edges or holes in leaves. They adore Their excellent camouflage makes them hard to spot. While katydids can cause a good amount of damage on young leaves, they’re an excellent little bug to have in the garden and are a good measure of a diverse garden ecosystem.

Solutions

  • Cultural: Handpick katydids when seen and remove affected plant parts. Cover young plants with fine mesh to prevent damage. Add decoy plants around the garden that attract katydids, such as calendula.
  • Biological: Attract predatory birds, spiders, and beneficial insects to keep numbers in check.
  • Organic: Neem oil or insecticidal soap can deter katydids without harming most beneficial insects.
  • Chemical: Use registered insecticides only for large infestations, applied carefully to avoid harming pollinators.

Pear & cherry slug

Pear and cherry slugs are the larvae of sawflies, leaving skeletonised leaves in their wake. They appear in late spring and early summer.

Solutions

  • Cultural: Handpick larvae and dispose of them in soapy water. Protect fruit trees with fine mesh.
  • Biological: Encourage lacewings, birds and spiders in the garden by planting diversely.
  • Organic: Apply Bacillus thuringiensis to leaves to lessen the number of slugs. Dust slugs with old wood ash to dehydrate them. Both methods should be reapplied consistently, especially after rain.
  • Chemical: Registered horticultural sprays may be used for heavy infestations.

Slugs and Snails

Slugs and snails are the gardener’s nemeses. They come out at night, especially after a big rain, and chew large, ragged holes in leaves, stems, and fruit, often targeting tender seedlings. Their slime trails are a telltale sign. Don’t confuse the common slug for the leopard slug, which is a beneficial garden cleaner that feeds on decaying matter, pet faeces, and even other slugs.

  • Snails
  • Snail
  • Beneficial leopard slug
  • Eco-shield Organic Snail & Slug Killer
  • Snail & Slug Barrier
  • Snail & Slug Killer

Solutions

  • Cultural: Handpick slugs and snails in the evening or early morning. Water plants in the morning to reduce damp conditions that favour slugs. Keep the garden tidy and free of hiding places. Place copper tape around plants or pots to deter snails and slugs.
  • Biological: Encourage natural predators such as frogs, birds and beetles.
  • Organic: Use beer traps, scatter crushed eggshells, or apply iron-based pellets safe for pets and wildlife.
  • Chemical: Chemical slug pellets can be used sparingly, but they pose risks to pets and beneficial wildlife.

Sap-Suckers

Aphids

Aphids are small, soft-bodied insects that cluster on new growth, sucking sap and leaving behind sticky honeydew that can encourage sooty mould.

  • Aphid
  • Ants farming aphid
  • Eco-oil
  • Yates Mavrik

Solutions

  • Cultural: Handpick heavily infested leaves and spray with water to dislodge colonies.
  • Biological: Encourage natural predators such as ladybirds, lacewings, hoverflies, and parasitic wasps by planting a diverse range of flowers and plants.
  • Organic: Insecticidal soap or neem oil works for targeted control. Dust diatomaceous earth directly on soft-bodies insects to kill them.
  • Chemical: Horticultural sprays labelled for aphids can be used if infestations persist.

Scale

Scale insects appear as small, immobile bumps on stems, branches, or leaves, often unnoticed until damage is significant. They weaken plants by sucking sap and, just like aphids, leave behind sticky honeydew that can encourage sooty mould.

Solutions

  • Cultural: Prune and remove heavily infested branches, maintain plant health with proper fertilisation and prune plants for better airflow.
  • Biological: Remove ants that farm scale to harvest the sticky honeydew they leave behind.
  • Organic: Horticultural oils smother the insects during active stages. Use sticky barriers to stop ants from climbing up trunks and farming scale.
  • Chemical: Systemic insecticides may be applied for severe infestations.

Whitefly

Whiteflies are tiny, moth-like insects that congregate on the undersides of leaves in large numbers. When disturbed, they rise in a small white cloud, making them easy to spot. They weaken plants by sucking sap, leading to yellowing, wilting, stunted growth, and premature leaf drop.

Solutions

  • Cultural: Regularly check the undersides of leaves, remove heavily infested plant material, improve air circulation, and use yellow sticky traps to monitor and reduce populations.
  • Biological: Encourage natural predators such as lacewings, ladybirds, hoverflies, and parasitic wasps, which all feed on whiteflies.
  • Organic: Spray with insecticidal soap, pyrethrum, Neem oil, or horticultural oils to suffocate both adults and nymphs. Multiple applications are usually required.
  • Chemical: Systemic insecticides can be applied in cases of severe infestation, but should be used cautiously to avoid harming beneficial insects.

Integrated Pest Management Tips

  • Monitor regularly: Catch problems early for easier control.
  • Encourage beneficial insects: Ladybirds, lacewings, parasitic wasps, and predatory mites are natural allies.
  • Rotate strategies: Alternate cultural, biological, organic, and chemical controls to reduce resistance.
  • Focus on plant health: Healthy, well-fed plants are more resilient to pests.

By combining observation, preventative care, and a balance of biological, organic, and chemical treatments, you can manage pests effectively while maintaining a vibrant and productive garden.

Come in to the Nursery and talk to one of our friendly garden experts today!

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