18 Common Garden Pests

Keep common pests out of your garden with these prevention tips and tricks.
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©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2008, Dorling Kindersley Limited

Photo By: Image courtesy of Gardeners.com

©2011, Dorling Kindersley Limited

©2011, Dorling Kindersley Limited

©2011, Dorling Kindersley Limited

©2011, Dorling Kindersley Limited

Photo By: Image courtesy of Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Slugs and Snails

Slugs and snails are enemies of the home gardener. They can devastate a garden practically overnight. Remove all slug hiding places from the garden and nearby. Keep them away with the old-fashioned method of placing small containers of stale beer in the garden.

Red Spider Mites

Red spider mites are a common sap feeding pest causing mottled leaves and early leaf loss on greenhouse and garden plants. Spider mites thrive in warm, dry conditions, and are a problem outdoors in late summer, especially in hot, dry weather. Check the underside of leaves for tiny green mites, which turn red in autumn, and fine silk webbing. Keep humidity high in hot weather and use the biological control Phytoseiulus persimilis, or try fatty acid sprays.

Carrot Flies

Carrot fly is the most problematic carrot pest. It can make a large proportion of the crop inedible. It is a small black bodied fly whose larvae feed on the roots of carrots and related plants. Rusty brown scars ring the tap roots of carrot. Female carrot flies lay eggs on the soil surface between late spring and early fall, and the small, cream larvae then tunnel into the roots causing unsightly brown lines. Prevent the low-flying females from reaching crops by growing carrots under fleece or in tall pots, erecting barriers, or sowing resistant cultivars.

Capsid Bugs

Capsid bugs spoil the appearance of plants by giving the foliage a tattered and distorted appearance. They are sap feeding insects that feed at the shoot tips, and on flower buds. Affected buds may fail to develop or open unevenly. Taste is not affected so control may not be necessary.


Aphids suck the sap out of tender plant shoots and leaves. They suck sap in through their beak-like mouths, while injecting leaves with their saliva. Drinking sap can weaken the plant, and injecting their saliva can spread diseases from plant to plant. Healthy plants can usually tolerate small numbers of aphids, but aphids can distort new growth and transmit viruses. Control them by squashing them, encouraging natural predators or spraying them with pyrethrum or fatty acids.


Birds eat insect pests in the garden yet they also eat entire fruits and vegetables or pick at them, making them inedible. Rather than attempting to keep them out of the garden, the best way to prevent damage is to cover susceptible pots with netting that is well secured at the base to prevent birds becoming tangled in it.

Field Mice

Mice and moles are pests that burrow under the garden, disturbing the roots. More importantly, they tunnel under ripening fruit, and up into it from the bottom in search of seeds. They can be controlled by traps, but use extreme caution when using poisons in the garden. Set mouse traps around vulnerable crops, but cover them to protect pets and other animals.

Flea Beetles

Small holes found in the leaves of brassicas, and arugula, radish and bok choy, are caused by these 1⁄8 – ¼ in (2–4mm) beetles. Heavy infestations can kill seedlings. Their presence is easy to spot because they leap off leaves when disturbed. Protect plants with horticultural fleece and, if necessary, control with pyrethrum.

Gooseberry Sawfly Larvae

Gooseberry sawfly larvae attack leaves of goosebery bushes, and red and white currants. The adult female lays its eggs on the underside of the leaves at the center of the bush and close to the ground. They can strip the bush bare as they move outwards along the branches. The small green caterpillars, usually with black spots, can be difficult to spot until damage is severe, so check bushes regularly. Pick them off by hand, spray with pyrethrum or use a nematode biological control.

Pea Moths

Pea moth caterpillars feed inside pea pods and are found at harvest. Consequently, pods need to be shelled with care, since caterpillars will be found alive inside the pod. Peas can be grown under netting to prevent female moths from laying eggs on plants.


These icky critters love tender new growth. Keep them in check by keeping the garden free of hiding places. You can catch earwigs in rolled up newspapers or in low cans filled with oil.

Tomato Hornworms

Finding holes in leaves and missing leaves? You likely have a tomato hornworm at work. These large green worms can gobble a mature tomato plant almost overnight. The worms hide under leaves during the daytime. Get rid of them by visiting your tomato patch at night, when they come out to feed. Knock worms into a container of soapy water. If you see a worm with white tic tac-looking things sticking out of it, leave it alone. It’s been attacked by a parasitic wasp, and it’s on a death march. You want those white eggs to hatch and release more wasps into your tomato patch.


Brownish-white caterpillars are a menace to root crops and potato tubers. They also kill seedlings and lettuce by eating through roots. Handpick, use Bt, parasitic nematodes or diatomaceous earth to treat.


The mealybug commonly feeds on cacti, succulents, and other houseplants. It causes leaf and stem distortion. Spray with thiacloprid or plant oils.


The grasshopper's mobility makes it hard to treat with ordinary insecticides. Try handpicking if you can stand it.

Leaf Miners

Leaf miners eat through leaf tissue leaving distinctive colored lines or blotches in the foliage where they have tunneled. Cover plants with garden fabric to shield from attacks. Spray with neem to discourage adults from laying eggs.

Vine Weevil Grubs

These pests bore into begonia and cyclamen tubers from fall to spring, and can kill plants, especially those in pots and containers. Use an appropriate insecticide.


The first line of defense against whiteflies is prevention. Check plants regularly. Avoid high-nitrogen fertilizers, which create young, succulent growth, which these insects love. Isolate infested plants from others and control the pests aggressively. For whiteflies, hang yellow traps coated with a sticky substance close to the tops of plants. Whiteflies are attracted to the color yellow, and once they land will be stuck and die. Hand-crush small populations of young aphids and whiteflies. Encourage natural enemies in the garden, such as ladybugs and lacewings, by planting diversity of plants and not spraying pesticides. As a last resort, use low-toxic sprays such as insecticidal soap, horticultural oil, and neem to reduce populations before they get out of hand. Repeat treatments every few days until the problem is under control.

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