We have listed below the most common insects we are asked about at our nursery here in Perth.
Aphids – are tiny soft bodies sap sucking insects that cluster on leaves and stems of plants and can hide on the undersides of foliage. They eat new shoots and buds, breed and multiply rapidly, transmitting viruses. New growth may look crinkled or stunted and the plant may eventually drop leaves. Infestations happen quickly and insects travel rapidly from one plant to another. They are similar to a beetle with an oval/pear shaped body. They are called Greenflies or plant lice in some countries. They can be colours ranging from green, white, yellow, grey, black, pink or grey. You can blast them with a jet of water or use an Insecticide product like Pyrethrum, Beat-a-Bug, Eco-Oil or a Scale Gun. They feed on plant sap and excrete plant sugar as honeydew which then increases the chance of black sooty mould. Healthy vigorous plants are less prone to attack.
Ants – Small piles of earth around holes in soil, lawns and paths indicate ant activity. They feed on sugary foods like honeydew secreted by aphids. They can colonize a plant and grow in large numbers. Though they don’t usually kill your plants, depending on the type of ant, their underground tunnels can interfere with root development and their nest building and burrowing can damage plant roots, soil structure causing poor plant performance. Ant dust, granules or sprays can be brought to eradicate them. An old home remedy you can also try is to mix powdered Borax with either Powdered Parmesan cheese or Icing Sugar and sprinkle near the ants, they will eat the mixture as it sticks to them, then they will take it back to kill the nest. Try making barriers, use Cinnamon, Turmeric, Black or Cayenne pepper and Vaseline. Strong odours like crushed mint leaves, Camphor and Lavender oil have proved good, also. Maple syrup in a saucer with boric acid around makes a good ant bait but keep out of reach of pets and children.
Azalea lace bug – These insects emerge in Spring. They are black, tiny, shiny bugs with lace-like mottled wings. They hide underneath the leaves sucking the sap. The top of the leaf will show fine white or silver mottling with lots of sticky brown/black poo underneath . Spray with Natrasoap which is a mite and insect spray which coats the insect causing it to suffocate and dry out. Remember to spray on the underside of the foliage and repeat after 5 days.
Black beetle – Both the adult and the larvae of the African black beetle can cause damage to the roots of a wide variety of plants. Their favourite choice is grass, they eat the roots. The grass dies in patches for no apparent reason, roots look brown and discoloured and clumps pull easily out in your hand. You can usually see them quite clearly in the grass. They are shiny black about 10-13 cm long and feed on the organic matter in the soil. If you see birds flocking to your lawn if may be an indication you have beetles. Lawn beetle grub killer granules can be brought to control these pests.
Borers – Borer larvae are mostly of beetles or moths but some are wasps or flies. They are hard to control once they enter the plant. They are an insect pest that spend most of their adult life feeding inside the roots and branches and tunneling beneath the bark and into the heart of many trees and shrubs. Injury can be long lasting and cause the death of a plant. Any plant can be susceptible but they attack stressed, injured or plants already dying from other causes, so avoid wounding plants as borers attack at weaker areas around cuts, plants that have been recently transplanted, hit by lightening, drought, flooding or mechanical cuts from whipper snippers, hedge trimmers, mowers and chain saws. Activity shows with a flow of tree sap and a sawdist like excrement. Foliage may drop and bark may crack. Remove dead limbs but generally chemicals have little value in controlling borer.
Bronze orange bug – These bugs damage citrus trees. The eggs are round and laid under the leaf in rows. Often called the stink bug because when disturbed they squirt out a horrible smelling chemical, it stains the skin and can cause a burning sensation when squirted in the eyes. They suck sap causing shoots and leaves to die and flowers drop early. They change colour as they age, starting green, then orange, brown and black. Treat with Confidor or try a home remedy of diluted detergent which dissolves their waxy eco-skeleton leaving them prone to disease, dehydration and predators.
Cabbage Moth (Diamondback Moth) – A destructive insect pest of leafy crops. It is a small moth with 3 white diamond shaped patterns on its back. Its active at dusk and throughout the night. They will fly during the day if disturbed from their resting place. They hang around Broccoli, Cauliflower, Kale and members of the Cabbage family. They have also been known to attack Celery, Rocket, Watercress, Beetroot and Brussel Sprouts. The green caterpillars leave round holes in the leaves and also do damage with their excrement which discolours the heads of cauliflower and broccoli. You can try a garlic spray, Vegetable dust, Success or Dipel caterpillar killer to try and deter and control his pest. Planting the herb Wormwood around is also meant to discourage the moth from laying eggs because it releases a strong oil.
Caterpillars – Moths and Butterflies lay eggs which hatch into caterpillars or grubs. They eat fruit and leaves before turning into a cocoon. They are extremely destructive especially to leafy vegetables. Try squashing when seen, or spray with Dipel or Success, neither are poison, so sprayed food plants can be eaten the same day after rinsing in water. They hide under leaves and as some are green they camouflage and are hard to see so always spray on the underside of foliage. Try planting strong scented plants like Rosemary and Mint in the garden as this has shown to keep caterpillar numbers at bay
Citrus Leaf miner – The larvae of this moth burrow tunnels between the surface of the leaves. Their tell tale sign is a silvery white wiggly line on the leaf and the leaf becomes curly, distorted and twisted. Severe infestations can slow down the growth of young trees. The moths fly at night and lay their eggs on new soft citrus leaves, then when the larvae hatch, they start munching into the leaf. Pest Oil deters egg laying. Do not use Pest Oil or White Oil if the temperatures exceed 30C as this may burn foliage. Remove damaged leaves from the tree.
Citrus Gall/ Rose Gall – Lumpy growths on young stems and stalks means a wasp has laid its eggs in the soft stem tissue and as the larvae hatches it eats the tissue around causing it to swell so the resulting gall is highly visible. Whilst it doesn’t kill the plant it reduces growth and in severe cases fruit production will decline. To treat remove all the limbs showing signs of swelling, put in plastic bags in the bin. Fertilise to encourage clean new growth. Rose Galls appear like abnormal lumps, bumps, tumour-like growths that mature to dark, hard, woody, swellings that eventually crack and decay. Other tumours may occur close by. They have a rough corky like surface and infected plants can become stunted and weak, if galls enlarge plants may wilt and die. Growths can occur on the trunk, stems, crown or roots. Prune off galls with sharp tools and disinfect them after, the soil could have bacteria in it so if plant is taken out, don’t plant in that area for awhile. The galls appear for one of two reasons, insects or bacteria. If an insect is feeding on the stem, its the roses way of forming a scab and healing its own wound.
Corky Scab – Affects a variety of cactus and succulents. Scabs form where cells in the leaf have burst or been damaged possible by insects but could also be adverse environmental conditions like being over-watered, excessive high light or high humidity. Damaged leaves will not recover and there is no spray that will help.
Earwigs – These insects are dark reddish-brown with long pincers at the end of their abdomen. They are scavengers and feed at night hiding during the day under mulch and leaf litter. They can do damage to field crops and gardens. They have been known to eat vegetables, roses and agaves. You can feed them to chickens or there are products you can buy, Garden insecticides or an organic alternative Beat-a-Bug.
Fruit Fly – Any fruit that is half grown is vulnerable to attack by fruit flies. In WA the most common is the Mediterranean Fruit Fly which starts appearing as the weather warms from August onwards. They lay their eggs under the skin of ripening fruit, maggots hatch and feed, spoiling the fruit, causing it to rot and fall off. Its slightly smaller in appearance than the house fly, its body is brown. Feed maggots to chooks or put them in sealed buckets of water or sealed plastic bags in the sun then dispose. Infested fruit has to be destroyed. You can try foliage baiting, cover spraying or make home-made remedies. Planting Basil and Lavender in the garden are natural pest repelling plants as they are strong smelling and help keep Fruit Fly at bay. There is a Fruit Fly Control concentrated liquid usually available at Garden Centres. Further information can be found by contacting the AG West Garden Advisory Centre. We now supply organic traps.
Grasshoppers – These jumping, chewing insects can munch through flowers, foliage and grass at a great rate. They feed at night and because they are green are difficult to see until they jump. They strip foilage and are very hard to control, most will not die when sprayed with insecticides. Try a pelletised product called Grasshopper and Caterpillar killer.
Hibiscus Beetle – Is a small shiny black beetle that eats the pollen and inner flower parts, causing fully developed flowers buds to fall off before they open. Other beetles can also attack Hibiscus. Try products like Pyrethrum or Carbaryl
Leaf-cutter Bee – The leaf cutter bee will show its been to your plants by leaving a distinctive circular hole perfect like a hole-punch has been used. It it not aggressive and will only sting you if you are a threat to it. They take chunks from soft new leaves usually from roses and take them back to build their nests. They don’t do any other damage but leave your bush looking tattered.
Locusts – Locusts are similar to grasshoppers, are about 6 inches long and can be in plague proportions and damage entire areas. They can devastate sporting grounds, vineyards, orchards and home gardens. High rainfall and warm temperatures aid the hatching of these pests. They are powerful fliers, can travel great distances and devour all vegetation in their path. They are nomadic and rapidly strip fields. A pellet is available called Grasshopper and Caterpillar killer which may help to rid these pests
Mealy bugs – These small insects are covered in a white mealy coating that looks like cotton, some have hairs attached to their bodies. The bugs feed by sucking on the plant juices of new tender leaves, the the leaves wither and yellow. They secrete a sticky substance called honeydew which attracts ants and makes it hard for the plant to breathe, then it turns to sooty mould. Mild temperatures and high humidity are perfect conditions for breeding. They infest Citrus, Ferns, Orchids and Ornamentals. They don’t like light so usually hide in the stems or on the underside of the leaves. Use an insecticide.
Millipedes – Is a slate grey/black long smooth bodied insect with lots of segments, each body segment has 2 pairs of legs, 20-45mm long. They have a life span of about 2 years. Outbreaks can number thousands and be a serious nuisance in the garden, outdoor areas and even inside houses. They may damage seedlings and crops. Rainy weather in Autumn and Spring stimulates activity, during hot weather they remain hidden in the soil. Attracted to light at night. They are vegetarian and live in plant debris and mulch and feed on decaying wood and leaf matter on the ground. When disturbed they commonly curl up to form a tight spiral and as a defense emit a pungent yellowish secretion. When stood on they give an unpleasant musty odour and leave yellow stains on the ground. Baysol can be used but this product is poisonous to animals and humans if ingested. Carbaryl also helps. Baygon and Mortein surface sprays can be used outdoors around the house to keep them outside.
Nematodes – Are microscopic colourless worms also called eel worms that exist in the soil. They work underground so are hard to detect. They burrow into the plant roots and take their water and nutrients leaving the plant weak, wilting, yellowing and prone to fungal disease. Even when the soil is moist on top the plant can still appear to be dying. By digging the plant up you can see tumour like growths on the roots. They are easily spread from one area to another by even run off water and dirt. They thrive in Spring and Summer. They are difficult to control and there is no chemical treatment available currently for residential use. Marigolds planted in the area are a help and crop rotation where you don’t plant the same crop in the same place the next year is a good idea. They are real nuisance in the vege garden and can ruin you whole crop for the season and stay long after the crop has failed. Add lots of organic matter to the area like aged Compost, Manure and Clay to control nematodes and pull out weeds and roots so it cuts off any food supply. They have been known to attach to Potatoes, Tomatoes, Capsicum, Eggplant, Chilli, Cucumbers, Pumpkins, Passionfruit, Pineapple, PawPaw, Melons, Strawberries, Bananas, Grapes and Peaches. A home made mix of Sugary syrup made with Molasses or plain sugar dissolved and spread around the area has been used before with some benefit.
Lace Bugs – Commonly found on Azaleas they lower the vigour of the plant and its flowering ability. Small soft bodied insects with large lacy wings they are hard to detect clinging to the underside of foliage and too little to see easily. They suck the juices from leaves giving a silvery mottled look to the leaf and leaving white or yellow spots on top and tiny black droppings. They excrete a sticky honeydew on the leaf which in turn causes sooty mould. Once plant has been damaged prune off minor damage and put in bin, this damage can not be repaired. Treating with a systemic insecticide is helpful for future attacks.
Psyllid – Sometimes called Blister mite this sap sucking insect mainly attacks Lilly Pillys and forms a pimple or dimpled look on the leave top and a hollow pit like a pock mark on the underside. Its tiny to the naked eye and can only be seen under a microscope or hand lens. It has a brown body and clear wings like a small cicada and feeds on new soft flushes of growth, distorting the leaves, its unsightly but not fatal to the plant. It can leave a crystal like honeydew substance on the foliage and that in turn causes sooty mould. Spraying Confidor onto new leaves coats them and makes it hard for the insect to attach and burrow.
Pittosporum beetle – A conspicuous 1 cm long oval black beetle with white spots, it damages young leaves by sucking the sap and decreasing the health of the tree. The affected leaves turn yellow and spotted. Young plants can be seriously damaged. A systemic insecticide can be applied.
Scale – Are Sap sucking insects which live under a protective coating. If you crape it with a fingernail and if comes off with goo underneath its scale. Its a round, small, flat insect which comes in many forms, black, red, brown, white, pink and soft or hard. They cause the leaves to yellow and drop, similar to the damage mealy bugs do to which they are related. Scale can cause the death of stems if infestation is heavy. It secretes a honeydew sticky substance which then causes sooty mould a black fungus to strike. The insect itself is wingless, circular or oval with no distinguishable body parts, no separate head, described once as bumps without legs! They attach to the mid-rib or stalk of plants. An oil based product like Pest, White or Eco-Oil can help smother the insect and make the stem slippery so it can’t attach.
Snails & Slugs – Snails and their cousins slugs are eating machines and can devour whole crops overnight. They leave irregular holes in leaves and if infestation is bad can kill plants. They love moist shady areas so when it rains out they come. Water in the morning so soil is dry come night fall when slugs who are nocturnal venture out and love wet damp conditions. Slugs chew plant leaves, and fruits leaving behind a slimy trail of mucous. Clean areas of old pots, logs, rocks, weeds, dead leaves and branches so they can’t hide. They dislike crawling over sharp surfaces so a barrier of scoria, stones, Jarrah sawdust or crushed egg shells will stop the onslaught somewhat and beer traps too! Snail and slug pellets scattered around will poison them but be careful they could poison animals and children too. There are options of pet friendly pellets from Multiguard.
Slaters– They are found all over Australia and although in large numbers can devastate a garden crop they are also beneficial as they feed on decaying matter then return nutrients that help build up the soil. The look like black oval shaped flat small insects with segmented bodies, 7 pairs of legs and 2 pairs of antennae, at the end of their body they have a pair of sensory organs. They are a land based crustacean related to crabs. They live on decaying plant and vegetable matter and are mainly busy at night, during the day hiding under mulch, pots, logs and leaf matter preferring a dark damp spot. They do damage to seedlings over night, ring barking them or just leaving stalks after chewing on the soft new leaves. They curl up into a tight ball as protection, when touched or disturbed. They multiply rapidly, are not harmful to humans and don’t bite. You can stomp on them or apply an insecticide which will need to be reapplied regularly or after rain. You can buy a selective Slater killer in granular form. They are crustaceans not insects so traditional insecticide treatments tend not to work. Frogs, lizards, birds and chickens eat them.
Stink Bugs – Can be one of the most common and most damaging insect pests in Summer and Autumn vegetable gardens. They can ruin a crop of tomatoes or peppers or damage a crop of peas or butter beans so badly as they are strong fliers and can smell suitable hosts from long distances. They are fruit and seed feeders. They have piercing sucking mouthparts, which they use to pierce the peel or hull of fruit and vegetables and eat the inner contents. On tomatoes and peppers damage usually appears as irregular shaped white or yellow blotches under the skin. Damage can also be noticed in crops like brocolli and cauliflowers. Stink bugs are a big family with many species but all have shield like shaped bodies and produce a strong disagreeable odour when handled. Green and brown are the most commonly noticed.
Thrips – Are tiny, long, slender insects with fringed wings but are so tiny are hard to find. They blend in their surroundings by being clear white, yellow, brown and black in colour. They are mobile and will crawl, walk, fly or jump. They readily live on any plant and can spread disease and cause damage to plants. They attack fruit, flowers and foliage in a variety of plants, but do like roses, azaleas, fruit trees and vegetables. By laying their eggs inside the plant tissue and feeding on the plant juices they leave their tell-tale signs as browning of petal borders, curled and defoliated leaves, blossoms that fail to open or not develop normally, leave a mottled silver brown appearance on the leaves, new shoots will become deformed and stunted, and you can sometimes see their dropping left on the plant as black sooty spots. You can try sticky traps hung in branches or use an insecticide. They have been known to sting people and pets and leave a rash. They go looking for water and if populations become large can be a big garden problem. Treat with an insecticide
Whiteflies – These are tiny flying sap sucking insects that congregate under leaves. They carry plant diseases. They are hard to control with a spray given the fact they fly away when disturbed and have a short life so you have to spray every 2-3 days to keep on top of it. They are not actually flies but are related to aphids and have a mealy white wax covering their wings and bodies. They feed, mate and lay many eggs on the underside of leaves. They are small only 1.5 mm long. Feeding on the flowing sap of bedding plants, strawberries, vegetables like cabbage, and tomatoes they cause leaves to yellow, shrivel and drop and weakens the plant, maybe killing it. They secrete a honeydew which leads to sooty mould and attracts ants. They like to feed on new growing shoots and can transmit viruses. You can often see a swarm of hundreds of them fly away from a plant when disturbed. The problem is often seen in plants kept in a glasshouse or indoors. A systemic insecticide can be used.
HOME MADE REMEDIES
Nematode Mix – Make up a sugary syrup mix with molasses or plain sugar, dissolve and pour over the area.
Beer Traps – Pour leftover beer into small bowls and leave these around the garden. Snails are attracted to the beer and drown in it. Fish out the dead snails each morning and the beer bowls will remain effective for days.
Copper Sulphate – As snails will not travel across a copper surface, put a heaped tablespoon of copper sulphate in a 9 litre watering can and fill can to dissolve. Go to the corner of your front verge and wet the verge with the mixture, then continue down the side and rear fences, leaving a wet trail. The snails have now been locked out of your property. It may be necessary to repeat the treatment after wet weather and then about once a year.
Vegemite Fruit Fly trap – Dissolve 1 teaspn Vegemite in 1 cup of warm water by stirring well. Pour into a soft drink bottle, seal the cap. Turn bottle upside down and drill 10 holes in for the flies to enter. Thread wire through two of the holes and hang trap near affected plants.
Soap Spray – Dissolve 3 teaspns liquid soap or washing detergent in 2 cups of water into a spray bottle and use it to control aphids on roses, citrus and other plants. The soap removes the aphids waxy coating and dries them out. You can also try soap spray on mealy bugs, ants and whiteflies.
Milk spray Fungicide – Any milk will do, skim, low fat or full cream. Mix 50ml milk into 450ml water then pour into a sprayer. Its effective against Powdery mildew when sprayed onto the leaves. Re-apply every time it rains. If leaves are badly infected this will have little effect though.
Garlic-chilli spray – Boil 4 onions – chopped, 4 hot chillis – chopped, and 2 garlic cloves – chopped in 2 litres of water for 15 minutes. Let the liquid cool overnight, then strain into a jar and add 2 tablespns of liquid soap. To spray, mix 10ml of your concentrate in 1 litre of water in a bottle and use to control aphids, whitefly, bronze orange bugs and other pests.
Oranges – Freshly squeezed orange halves laid flesh down around the areas where slaters are doing damage on dry days and they will crawl all over them. Put in bag in the bin. Citrus peel or rind added to soapy water in a spray bottle will deter ants.
Baking Soda – is an inexpensive control for powdery mildew on plants, its best used as a preventative offering minimal benefits after plants are infected. A mix of 1 tblspn of baking soda, 1/2 teaspn of liquid soap and 1 gallon of water mixed together. Can be used to ward off ants also. Unused liquid can not be stored and re-used. It can burn the leaves of some plants so water plants well before use and don’t apply in full sun. Try and get the under side of the leaves too.
Crushed egg shells – used eggshells crushed and cooked in the oven till they are crispy are good to put around young freshly planted seedlings as insects like snails and slugs which have soft underbellies don’t like crawling over sharp things and the eggshells will be like glass to them so many people have said this remedy helps to deter these pests!
Talcum Powder – Get rid of ants nests by covering the nest in the cheapest talcum powder you can find.
Hair – Slugs hate hair as it sticks to them. Ask the hairdresser or dog groomer for a bag of cuttings and spread around plants.
Vinegar – when trying to get rid of weeds between your pavers pour white vinegar on them to kill them and it won’t harm your pets.
Spent Coffee grounds – To keep earwigs and millipedes at bay that can hide under straw that you may have put around plants as a mulch, e.g strawberries (so the fruit does not hit the soil and develop root rot) put spent coffee grounds over the ground. To kill slugs and snails make up one part espresso coffee( not instant) to 10 parts of water, spray over the surface of leaves and soil where snails and slugs might crawl. Re-apply after heavy rain.
Sawdust –Snails and slugs do not like dry surfaces. Continuous lines of sawdust and ashes can be used as barriers but their effectiveness is drastically reduced once they become wet.
Horticultural oil – This controls most insect pests, including scale, aphids, white fly, leaf miner, mealy bug and mites. To make, get 2 cups of vegetable oil and 1/2 cup of dishwashing detergent. Shake together in a jar, where the mixture will turn a milky colour. Add 2 tablespoons of this concentrate to a litre of water and its ready to spray.
BENEFICIAL INSECTS IN THE GARDEN
Bees – Are needed for pollination of flowers
Ladybirds – eat aphids, scale, thrips, mealybugs and mites
Spiders – feed on insects and are very important in preventing pest outbreaks
Worms – aerate the soil and worm castings add beneficial nutrients to the garden
Praying mantis – Is a predator of insects, mites and eggs so cleans up your garden pests