Common Garden Pests

The unpleasant creatures and organisms that disfigure and kill your garden plants have to be controlled. Already systematic insecticides give protection against sap sucking greenflies for several weeks to roses and other flowering shrubs.

Chemical companies are producing mixed compounds that dispose of many fungi and blights with a single squirt of the garden spray. Plant breeders are constantly trying to produce varieties immune from or resistant to pests and diseases. Nevertheless, you cannot afford to relax. As the following pictures show, inspite of chemical breakthroughs there are still plenty of enemies to be fought in every garden.

The following list of some common garden pests shows both the damage they do and the recommended methods of control.

  • Ants
  • Aphides
  • Beetles
  • Capsid bugs
  • Caterpillars

Ants

These small insects are often a nuisance in the garden. They swarm over plants infested with aphids in search of honeydew excreted by them, and transport them bodily to fresh crops. Ants build nets in the soil of flower borders and by tunneling underground damage the roots of herbaceous plants, and often kill them. In frames and greenhouses they feed on newly sown seeds. Ripe fruits are often attacked by swarms of ants.

To control ants, dust the soil with DDT or BHC. Nests may be destroyed by pouring liquid derris, petrol, boiling water or inflammable carbon disulphide on them.

Aphids

Widespread pests, also known as greenflies or blackflies. They cause severe damage to many decorative plants and most fruits and vegetables.

The many different species of aphides attack tissues of stems, leaves and fruit to suck out the sap. Direct damage to the plant includes leaf curl and distortion of young shoots.

As virus carriers, aphides indirectly damage many garden plants by sucking infested sap by a diseased plant and carrying it into a healthy one.

The spores of the sooty mould fungus germinate in the excreta of aphides, producing a thick sooty covering on the leaves of apples, plums, pears, phlox and asters. The mould does not harm the plants but it in unsightly and may spread to the fruit.

As soon as the first aphides are seen they must be destroyed, as they multiply at an alarming rate and quickly build up large, dense colonies of young shoots and undersides of leaves. In summery spray or dust affected trees and shrubs, flowers and vegetables with insecticides containing BHC, DDT, derris, malathion or nicotine.

As an alternative, use a systematic insecticide, based on menazon or dimethoate and spray it o n the foliage or water it into the roots. It will become absorbed in the sap stream of the plant, making it toxic to aphides.

During the dormant period, control aphides by winter washing with tar oil or DNOC; or spray in early spring with one of the insecticide listed above.

Apple aphids
Apple aphids

Apple aphids

There are several species that attack apple and pear trees . The small, shiny black eggs are clearly visible on twigs and branches in the autumn. To prevent these eggs hatching  out and damaging the young leaves, flowers and fruitlets, spray the trees in winter with tar oil and DNC. At bud burst, applications of DDT, BHC or malation may be necessary.

Rose aphids. Color from green to pink. Infests shoots and buds. Attacks scabious and strawberries.
Rose aphids. Color from green to pink. Infests shoots and buds. Attacks scabious and strawberries.

Rose aphis (greenfly)

Frequently attacks the leaves and flowerbuds of roses and scabious, causing stunted growth. Apply melation or a systematic insecticide when leaves appear and repeat when necessary.

Aoot aphids. Confined chiefly to water lettuce. First symptoms are yellow and wilting leaves.
Aoot aphids. Confined chiefly to water lettuce. First symptoms are yellow and wilting leaves.

Root aphis

Chiefly infests the roots of autumn and winter lettuces. The main symptom is wilting of plants. If this is recognized in time, applications of root drench containing malathion, watered into the soil around the plants, may prevent further damage.

Cabbage or mealy aphis
Cabbage or mealy aphis

Cabbage or mealy aphis

Attacks most brassicas, especially cabbages and Brussels sprouts. The tightly packed colonies must be destroyed early, while it is still possible to spray the deviling hearts and bottons. Spray with malathion or nicotine or use a systematic insecticide.

Black bean aphis (blackfly). Attacks beans, root crops, rhubarb, nasturtiums and dahlias
Black bean aphis (blackfly). Attacks beans, root crops, rhubarb, nasturtiums and dahlias

Black bean aphis

Found on top of growths of all types of beans and spinach. Similar black aphides occurs on rhubarbs, nasturtiums and dahlias. Attacks by this pest cause a check on growth and subsequent poor crop. Spray with  derris, malathion or a systematic insecticide.

Wooly aphids. Often on apple trees. The 'wool' is a secretion of sap-sucking aphides.
Wooly aphids. Often on apple trees. The 'wool' is a secretion of sap-sucking aphides.

Wooly aphis.

A pest of apple trees and of related ornamental shrubs and trees such as crab apples. The white wooly secretions on the bark often leave ugly, corky galls, leading to stunted or deformed growth. Paint individual colonies with dilute solution of malathion of gamma BHC, or apply a drenching spray of malathion insecticide in may. Winter wash with tar oil.

Aphides under glass

Colonies of aphides can buildup more rapidly under glass than they can outdoors. Control methods in the greenhouse are same as outdoors but the use of green house smoke is more effective. These contain insecticides, obtainable as combustible mixture of in aerosol form.

Beetles

Cockchafer(may bug). adults and grubs attacks shrubs, perennials, and vegetables.
Cockchafer(may bug). adults and grubs attacks shrubs, perennials, and vegetables.

Cockchafers (may bugs)

Both the young and adult beetles and the young larvae cause extensive damage to many plants. The adult beetles attack the leaves of many trees and shrubs, and the larvae feed on the roots of herbaceous plants, fruits and vegetables. The fat white larvae live in the soil for 3-4 years before attaining maturity. They are not easy to control, though BHC raked into the soil can be effective. When the soil is being dug over, the larvae can be picked up and killed.

Other grubs found in the soil include the larvae of garden chafer and rose chafer, which feed on the roots of grass. The adults feed on the larvaes and fruit of apples and pears, and on the leaves of roses and shrubs. Control as for cockchafers.

Flea beetle. Cause of holes seen in the leaves of brassica, wallflower and alyssum seedlings.
Flea beetle. Cause of holes seen in the leaves of brassica, wallflower and alyssum seedlings.

Flea beetles

Numerous species of these small black and yellow beetles attack vegetables. They damage brasicas, often covering the leaves with holes and they can destroy a whole seedling bed by chewing off young plants at ground level.

To prevent attacks, treat seeds with a proprietary seed dressing or dust the drills with BHC or DDT before sowing. Spray or dust the seedlings at fortnightly intervals with these insecticides until the plants are well developed.

Raspberry beetle. Larvae feed on the fruits of raspberries, blackberries and loganberries.
Raspberry beetle. Larvae feed on the fruits of raspberries, blackberries and loganberries.

Raspberry beetle

The adult beetles appear in May and feed on the flower buds of raspberries, loganberries and tivated blackberries, where they lay their eggs. The larvae feed on the young fruitlets and unless control measures are taken, much of the fruit will be maggoty. Spray with malathion or derris ten days after flowering begins and repeat a fortnight later.

Capsid Bugs

A large family of sucking insects that chiefly attack fruit trees and herbaceous plants. They are seldom troublesome on vegetables or in the greenhouse.

The following are among the more common capsid bugs.


Apple capsid bug damage
Apple capsid bug damage

Apple capsid bug

Green nympis hatch out in April and May, and feed on the sap of the foliage. These insects are  related to aphides but are larger  (about ¼ in. long when mature) and do not cluster in colonies. The adult bugs are green and after the petal fall they begin to feed on the fruits, puncturing the skin and causing raised brown marks.             

Control by spraying the trees with DNOC, in petroleum oil in winter or with DDT and BHC in spring and summer,

Bishop bug. Holes leaves and distorts blooms of chrysanthemums, zinnias and dahlias.
Bishop bug. Holes leaves and distorts blooms of chrysanthemums, zinnias and dahlias.

Bishop bug (tarnished plant bug)

These bugs which have a pattern like a bishop’s mitre on their backs, infest the leaves and flower buds of chrysanthemums, dahlias and zinnias, disfiguring and stunting the shoots as soon as any damage is seen, spray or dust with DDT or BHC.

Common Green Capsid Bug
Common Green Capsid Bug

Common Green Capsid Bug (lygus)

The small wingless nymphs make holes in leaves of currant bushes, gooseberries, blackberries, cherries, raspberries, strawberries, peaches and pears. After maturity, the green bugs leave the crop in June and July to feed on herbaceous plants or weeds. To control, apply winter washes of DNOC in petroleum oil, or spray with DDT or BHC in spring.

Caterpillars

The soft bodied larvae of numerous species of butterflies and moths which themselves cause damage to plant life. Caterpillars however, are a considerable menace in the garden. They feed mainly on foliage, but also attack roots, seeds and bark of a wide variety of crops. The life cycles of various species are similar. Caterpillars hatch out from eggs in spring and begin to feed immediately. The pupate in early summer, sometimes in a tiny cavity in the soil, or suspended from a sheltered wall. The following spring the adults break out of the chrysalis to mate.


Buff-tip moth
Buff-tip moth

Buff-tip moth

The black headed caterpillars with downy, orange striped bodies, hatch out on foliage of fruit trees, especially cherries and are voracious feeders in July and august. Pick off individual caterpillars or if the attack is severe, spray with DDT or derris.

Cabbage moth feeding on red cabbage leaf
Cabbage moth feeding on red cabbage leaf

Cabbage moth

The green, or grey caterpillars feed in early summer on the laves and hearts of cabbages, and may completely strip the plants. These serious pets attack all types of brassicas as well as flowering plants such as nasturtiums, wallflowers and stocks. Spray with DDT as soon as the caterpillars are seen, paying particular attention to the underside of the leaves.

Codling moth. The caterpillars are familiar maggots found in apples during the autumn.
Codling moth. The caterpillars are familiar maggots found in apples during the autumn.

Codling moth

The small, pale pink caterpillars are serious pests of apples, boring into the fruits and making them maggoty. Codling moth caterpillars leave the fruits in the autumn to pupate on the bark of the tree.

During the dormant period, spray with petroleum or tar oil. As a further precaution apply malathion or DDT with BHC during spring and summer. Alternatively, trap the cocoons by trying old sacking round the trunk by mid July or caterpillars to pupate in. remove and destroy the sacking with the cocoons inside before spring.

Cutworm larvae from top: sandhill cutworm, variegated cutworm, black cutworm, dingy cutworm, claybacked cutworm
Cutworm larvae from top: sandhill cutworm, variegated cutworm, black cutworm, dingy cutworm, claybacked cutworm

Cutworms

These fat caterpillars, which may be green or mud colored, inhabit the top layers of the soil during the day. At night they come up to feed on the roots, stems and leaves of numerous herbaceous plants and of vegetables such as beet, onions and carrots. Control is not easy, as the pests are seldom detected until the damage has been done. The best cure is to dust DDT on the ground near the affected plants. BHC can also be used on flower beds. Do not apply it to root vegetables.

Swift moth. The caterpillars feed on vegetable roots, and hollow out bulbs and tubers.
Swift moth. The caterpillars feed on vegetable roots, and hollow out bulbs and tubers.

Swift moth

These large white caterpillars live in the soil, where they attack the roots of a wide range of plants. They attack most vegetables, strawberries and herbaceous plants such as dahlias, paeonies, irises, daffodils and delphiniums.

These large white caterpillars live in the soil, where they attack the roots of a wide range of plants. They attack most vegetables, strawberries and herbaceous plants such as dahlias, paeonies, irises, daffodils and delphiniums.

Tortrix moth damage
Tortrix moth damage

Tortrix moth

There are several species of tortrix moth caterpillars, with differing colors. All can be distinguished by their habit of wriggling backwards when disturbed. They feed on foliage of ornamental trees and shrubs and roses. The leaves are fastened together with a cobwebby substance making it difficult to penetrate with a spray, and hand picking is the easiest form of control.

Vapourer moths feeding on leaves
Vapourer moths feeding on leaves

Vapourer moth

The hairy, bright yellow caterpillars occasionally infest the leaves of fruit trees and roses.

Routine sprays with DDT, BHC, derris or malathion are effective.

Winter moth. In spring, the caterpillars attack the buds and foliage of fruits trees and bushes.
Winter moth. In spring, the caterpillars attack the buds and foliage of fruits trees and bushes.

Winter moth

The green caterpillars are active early in the year on fruit trees and bushes, related ornamental trees and shrubs, and roses. They begin to feed as soon as the leaf buds break, and can cause considerable damage to young leaves and fruitlets in a short time. The best method of control is applications of DDT or trichlorphon; on fruit trees this should be a routine spring procedure. DNOC in petroleum oil gives a partial control, and grease banding in the autumn is another method of keeping winter moth at bay.

Pea moth. Maggoty peas are the result of pea moth eggs laid on or near the developing pods.
Pea moth. Maggoty peas are the result of pea moth eggs laid on or near the developing pods.

Pea moth

The pale yellow caterpillars attack pea pods, feeding on peas and causing them to be maggoty. At flowering time, spray the young plants with DDT and again ten days later.

Moths under glass

Tomatoes and chrysanthemums are the pants most liable to attack by caterpillars. They feed on voraciously on the foliage and must be destroyed as soon as detected with sprays of DDT, gamma-BHC or malathion.

Eelworms

These minute, worm-like creatures are invisible to the naked eye. They are widely distributed in the soil, and attack a great variety of food crops and herbaceous plants.

Chemical control is impractical and difficult, and in nearly all cases the only remedy to destroy the infested plants and avoid replanting the host plants in the same plot of land for at least three years.

Damage to leaf caused by Strawberry Eelworm
Damage to leaf caused by Strawberry Eelworm

Strawberry Eelworm

The presence of strawberry eelworms is difficult to diagnose, as signs of attack are similar to those of various virus diseases. The chief symptoms of infestation by these pests are puckered strawberry leaves, silvery patches near the abnormally thickened midribs and swollen leaf stems. Onions, parsnips, and narcissi are also attacked.

Burn all the plants in an infested bed and do not plant any more strawberry plants in the same patch for at least 3 years.

Potato root eelworm damage
Potato root eelworm damage

Potato root eelworm

These are the most serious potato pests, and are very common. They also attack tomato grown under glass. Affected potato plants are stunted, the leaves turn yellow and the crop of tubers is severely reduced. The minute eggs are present in cysts (dead female eelworms), attached to roots and tubers. There is no adequate chemical control against potato eelworms. Rotation of crops is an effective cultural method.

Chrysanthemum Eelworms

A fairly common and serious pest for chrysanthemums outdoors and under glass. The microscopic creatures live in the tissues of leaves and buds. Symptoms of attack are dark patches on the lower leaves, followed by leaf drop and blind flowers. Asters, dahlias, and pyrethrums are also attacked. Dig up and burn all the infested plants.

Stem & bulb eelworm damage to bean stem
Stem & bulb eelworm damage to bean stem

Stem and bulb eelworms

Narcissi, hyacinths, irises, daffodils, tulips and onions are the chief hosts of these serious pests; though rhubarb, plox and other herbaceous plants are also attacked. The small eelworms survive in the soil, where they tunnel into bulbs and stems, causing twisted growth and deformed flowers and leaves. The leaves often show small swellings. Infested bulbs are soft to the touch and may have a white wooly substance on the base. A cut across the bulb will reveal dark rings on the white flesh.

There is no effective chemical control, but healthy bulbs from reputable sources are usually sterilized against eelworm. Infested plants must be dug up and burnt, and bulbs should not be planted in the same bed for three years.

Root knot eelworm damage
Root knot eelworm damage

Root knot eelworm

These small pests produce nodules or swellings on the roots of greenhouse plants such as cucumber, gloxinias, lettuces, and particularly tomatoes. The roots function poorly, producing poor growth. The nodules house female cysts, which release young eelworms into the soil to infest healthy plants. Unless the soil is treated, the cysts will survive to attack the next crop.

Infested tomato plants can be temporarily helped by a layer of peat round them, so that the aerial roots can develop in a healthy medium. In the autumn, destroy the plants, and then sterilize the soil with dazomet or formaldehyde. In a small green house replace the soil altogether. Infested soil must not be deposited in the garden, otherwise the eelworms will spread to the roots of carrots, celery, parsnips and clematis in the open.

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Comments 2 comments

Lhanikis 22 months ago

Biological and Chemical control? Yellow crazy ant?For blioogy I'm looking at biological and chemical control over introduced species such as the yellow crazy ant. Yet in regards to a method of control such as removing a producer of their food supply ie. the scale insect, I was unsure as to whether this would classify as biological control. By definition biological control is The control of a pest by the introduction of a natural enemy or predator'. Is there another term used for this control, rather than biological???Any help would be much appreciated Thanks


Open 22 months ago

I have that theme song stuck in my head now I use re-usable shopping bags to keep it "green"! I also use/make&sell reslabue sandwich bags! I'm all kinds of green now that think about it! ha

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