How do I stop ants climbing my fruit tree?

Treat the aphids, scale or mealybugs the ants are farming, wrap the trunk about 45 cm above the ground and apply horticultural glue over the wrap (never directly on bark), prune branches that act as bridges, and use a lidded ant bait station at the base.

Are organic sprays safe for bees?

Not all. Pyrethrum kills bees on contact and spinosad is toxic while wet. Oils, soaps, Bt and potassium bicarbonate are lower risk. Never spray open flowers.

Which snail bait is safe with dogs?

None is completely safe. Metaldehyde and methiocarb are highly toxic; iron-based baits are less toxic but can still harm dogs in larger amounts. Beer traps and hand-collecting are pet-free alternatives.

How do I save this guide to my phone?

On iPhone use Safari, Share, Add to Home Screen. On Android use Chrome, the menu, Add to Home screen.

Garden Pest & Disease Guide: Diagnose, Treat & Prevent (Organic Options)

Q: Does milk really work on powdery mildew?

Yes. A zucchini study found milk sprays of 10% or stronger, applied twice a week, controlled powdery mildew. Mix 1 part milk with 9 parts water.

Q: When should I spray for peach leaf curl?

At leaf fall in late autumn and again at bud swell in late winter, with copper or lime sulfur. Once curled leaves appear it is too late for that season.

Garden Pest & Disease Guide

Work out what's attacking your plants, then fix it: practical steps first, organic options next, and the right product if you need one. Written for Australian gardens, with quantities for homemade sprays scaled to your sprayer.

Partner tool: the Australian Garden Planting Planner tells you what to plant and when for your climate. This guide helps you keep it alive. Tap any plant name to jump straight to its planting guide.

Stopping ants climbing trees

Ants on a tree are usually a symptom. They're farming aphids, scale or mealybugs for their sweet honeydew, and protecting them from ladybirds and wasps. Stop the ants and the natural predators move back in.

Find the herd. Follow the ants to new shoots and under leaves, and treat those pests first (oil or soap spray).
Wrap, then glue. Wrap the trunk about 45 cm above the ground with a strip of tape or cardboard (sticky side out if tape), overlap it by about 10 cm, then spread a 10 cm band of horticultural glue on the wrap. Never put glue straight on bark. It can damage thin bark on young trees.
Cut the bridges. Prune any branch touching a fence, wall, stake or another plant. Ants will use it to bypass the band.
Bait the nest. A lidded bait station at the base lets workers carry bait back to the colony. See the sugar-borax bait.
Maintain it. Refresh the glue when it's dusty or bridged with debris, and remove the band at the end of the season so it can't restrict the trunk.

In hot weather, use glue sparingly so it doesn't run. Check bands regularly for trapped wildlife.

Barriers that beat sprays

Insect netting on brassicas

Cover broccoli, cabbage and kale the day you plant them. No white butterfly eggs means no caterpillars, and no spraying all season.

Wildlife-safe fruit netting

Use mesh you can't poke a finger through (about 5 mm or less), pulled taut over a frame and secured at the ground. Loose, wide-mesh netting traps birds, bats and possums, and some states now require wildlife-safe netting.

Fruit bags

Slip exclusion bags over individual fruit clusters after pollination. They stop fruit fly, codling moth and birds on small trees.

Possum collars

A smooth metal band about 60 cm tall around a free-standing trunk stops possums climbing, as long as no branches touch a fence or roof.

Seedling collars

Cut the top and bottom off a plastic bottle and push it into the soil around each seedling. It stops cutworms and earwigs until plants toughen up.

Sticky traps

Yellow cards catch whitefly and fungus gnats; blue cards catch thrips. Use them only where needed, because they catch some good insects too.

A fruit fly plan that works

Fruit fly attack even hard, green fruit, so start 6–8 weeks before harvest. No single method is enough on its own; combine them.

Monitor: hang a trap about 1.5 m high in shady foliage to see when flies are active.

Bait: spot-apply a protein bait to trunk and leaves (not fruit) each week and after rain.

Exclude: fine netting or fruit bags, sealed at the base, are the most reliable protection.

Clean up: collect fallen and stung fruit daily. Kill maggots by freezing, cooking, or sealing the fruit in a plastic bag in the sun for about 14 days, then bin it. Never compost it.

Team up: flies travel between yards, so share the plan with neighbours.

Tasmania and parts of South Australia have strict rules about moving fruit in. WA also has Mediterranean fruit fly (Medfly). Check your state agriculture department for local rules.

Stop rot & mildew before it starts

Water mornings, at the base

Most fungal diseases need wet leaves overnight. Watering the soil in the morning lets foliage dry fast. Drip irrigation is ideal.

Give plants air

Space plants as the label suggests, prune crowded centres, and stake tomatoes up off the ground.

Mulch to stop splash

Rain and hoses splash soil-borne spores onto lower leaves. Mulch stops it, but keep it about 10 cm away from trunks to prevent collar rot.

Rotate crops

Don't grow tomatoes, potatoes, capsicum or eggplant in the same bed for 3 years. They share diseases.

Clean tools

Wipe secateurs with methylated spirits between diseased plants so you don't spread infection.

Bin, don't compost

Diseased leaves, mummified fruit and myrtle rust material go in the rubbish bin. Home compost rarely gets hot enough to kill spores.

Recruit the good guys

Ladybirds, lacewings, hoverflies, parasitic wasps and predatory mites eat aphids, scale, mites and caterpillars for free. Broad-spectrum sprays kill them too, which is why pests often bounce back worse after spraying.

Plant insect-friendly flowers

Small-flowered plants such as alyssum, and herbs left to flower, feed adult hoverflies and wasps.

Spray last, and smart

Squash, hose or prune first. If you spray, spot-treat the problem plant with the most targeted product, late in the day.

Add water

A shallow dish with stones helps bees and beneficial insects through hot weather.

Chooks & ducks

Let them patrol beds between crops. They clean up snails, slugs and grubs (keep them off seedlings).

Spray safety

The label is the law. In Australia, garden chemicals are registered by the APVMA for specific plants and pests. Use them only as the label directs.
Check the withholding period before harvesting edibles: it's the minimum days between spraying and picking.
Protect bees: never spray open flowers; spray late afternoon or evening when bees aren't foraging.
Not in heat or wind: oils and sulfur can burn leaves above about 30 °C, and wind carries drift onto you and your neighbours.
Wear gloves and eye protection, keep products in their original containers, and store them locked away from children and pets.
Homemade sprays aren't registered products. Always test on a few leaves first and label your bottles.

Frequently Asked Questions

Ants climb trees to farm aphids, scale and mealybugs for honeydew. Treat those pests, then wrap the trunk about 45 cm above the ground and apply a band of horticultural glue over the wrap (never directly on bark). Prune any branches touching fences or other plants, and put a lidded ant bait station at the base.

Yes. A greenhouse study on zucchini (Bettiol, 1999) found milk sprays at 10% or stronger, applied twice a week, controlled powdery mildew as well as or better than the fungicides tested. Mix 1 part milk with 9 parts water and spray in the morning.

Not all of them. Pyrethrum is natural but kills bees and beneficial insects on contact, and spinosad is toxic to bees while wet. Oils, soaps, Bt and potassium bicarbonate are much lower risk. Whatever you use, never spray open flowers, and spray late in the day.

None is completely safe. Metaldehyde and methiocarb pellets are highly toxic to dogs. Iron-based baits are much less toxic but can still cause harm if a dog eats a lot. Beer traps, night-time collecting and chooks are pet-free alternatives. If your dog eats any bait, go to a vet straight away and take the packet.

At leaf fall in late autumn, and again at bud swell in late winter, with copper or lime sulfur. Once curled leaves appear it's too late for that season. Pick off affected leaves and keep the tree fed and watered.

iPhone: open this page in Safari, tap Share, then "Add to Home Screen". Android: open it in Chrome, tap ⋮, then "Add to Home screen". Perfect for taking out into the garden.

Disclaimer: This guide is general information for home gardeners. Always read and follow the label of any product you use; labels are the legal instructions for use in Australia. Homemade sprays are not registered products: test them on a few leaves first and use at your own risk. Brand names are examples only and Everyday Calculators is not affiliated with any manufacturer. For suspected exotic pests or diseases, contact your state agriculture department or the Exotic Plant Pest Hotline.

Garden Pest & Disease Guide

What's wrong with my plant?

What to watch for this season

Pests & diseases A–Z

Stopping ants climbing trees

Barriers that beat sprays

A fruit fly plan that works

Stop rot & mildew before it starts

Recruit the good guys

Spray safety

Product guide: what works best on what

Make your own organic sprays

Myths worth skipping

Frequently Asked Questions

What's wrong with my plant?

What to watch for this season

Pests & diseases A–Z

Stopping ants climbing trees

Barriers that beat sprays

A fruit fly plan that works

Stop rot & mildew before it starts

Recruit the good guys

Spray safety

Product guide: what works best on what

Make your own organic sprays

Myths worth skipping

Frequently Asked Questions

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