Insects that are injurious to our plants and vegetables-1

Eating before beauty

Uploaded to Commons from Flickr by Mindmatrix
Uploaded to Commons from Flickr by Mindmatrix | Source

Introduction.

Probably every plant supplies either food or shelter,or both ,to one or more insects or other animals and fungi. Because our garden plants and the vegetable land provides a greater diversity than one would find in an area of uncultivated land, the abundance of food and shelter provided encourages the multiplication of objectionable guests.

In the USA where fruit plantations frequently extend to hundreds of acres, it is a matter of life and death for the fruit grower to take all possible precautions against fungi,or insects obtaining a foothold on his plantations.

Even in our gardens and allotments,though on a much smaller scale than that formerly mentioned,care needs to be taken if our prized flowers and vegetables are not to be lost or damaged. In order to wage war successfully with plant pests it is essential to possess a good knowledge of the life history of the pest,so as to know where it is lurking at each stage of its existence,and at what stage it can best be exterminated. The number of such pests is considerable.

Blotches and discolouration for example are often attributed to frost or cutting winds when they are in fact, the outcome of attacks by fungi or aphids.

Aphid

Aphid not only damage plants but spread fungal attacks and viruses.
Aphid not only damage plants but spread fungal attacks and viruses. | Source

Ladybirds {Lady bugs} should be encouraged they consume vast quantities of aphids both as adult and in their larval stage.

Tansfered from Flickr by FlickrreviewR  to Commons
Tansfered from Flickr by FlickrreviewR to Commons | Source

Identifying helpful insects Ladybug larvae also devour aphids. Courtesy of MrBrownThumb;standard you tube license

Operophlera brumata a winter moth

' Nordisk familjebok'
' Nordisk familjebok' | Source

Prevention is better than cure {as they say}

Prevention is better than cure,and fortunately there are a number of ways in which attacks can be weakened and diminished by carrying out some simple tasks. For example ,if the soil is turned over in autumn or winter,any insect larvae or pupae,which may be concealed within it ,will be exposed to weather and killed or eaten by birds. Insectivorous birds such as members of the tit family or the starling,do us a great service in this respect,and therefore should be encouraged.

Insects and fungal diseases can usually maintain themselves on more than one species of plant. Hence the chances are, that if a ground occupied one summer with a given species of plant,is occupied the next summer with a different species,or better still with a species belonging to an entirely different order, the insect or fungi may well be starved out by the latter. Therefore regular changing {rotation} of plants and especially vegetables is necessary.

Crops or plants ,owing to being planted in the wrong soil or situation,or those that are met with unfavourable weather,are more prone to attacks,and seedlings especially are frequently attacked. When a pest has become established remedial action is required,that may be spraying,trapping or even hand picking.

Aphids and scale insects and beetles feed on plants both in the larval and adult stages of their lives. Moths and Sawflies,feed on plants during their larval stage only. In combating attacks, the eggs and chrysalis may be destroyed in winter and the larvae during spring and summer.

Garden cleanliness is important to the grower,moss,lichens and dead bark afford shelter to the eggs during the winter and care should therefore be taken to keep the trunks and stems of fruit trees as clean as possible.

Here in the first in this series we look at some moths and their larvae which are considered to be pest species in our gardens and allotments.

March moth Alsophila aescularia

Source

Illustration of the wingless female

Moths of the British Isles
Moths of the British Isles | Source

Caterpillar of the March moth Alsophila aescularia

Source

The winter moths

There are in the UK,three main species of 'winter moths' the one commonly referred to as the Winter moth, Operophters brumata, The March Moth,Alsophila aescularia and The Mottled Umber,Erranis defoliaria. All three are widespread and important pests of fruit trees and ornamental plants in Britain and northern Europe.

Wingless females emerge from the pupae that has been concealed beneath the soil and early spring, mate with the winged males and then crawl up the trunks and stems and commence to lay in the region of 200 eggs each. The winter moth emerges in October to December,Mottled Umber October to march and March moths emerge from June until April.

The Winter moth and the Mottled Umber females lay eggs singularly or in small clusters near buds and in crevices in the bark.The March moth lays distinctive bands of eggs around the twigs. The eggs hatch from March onwards and the caterpillars feed on the buds and young leaves as they develop. caterpillars of all three species are similar in structure but differ in colour.

Those of the Winter moth are usually green with three longitudinal stripes. All grow to the length of about 30 mm and most finish feeding from mid May to June. They then go in the soil to pupate. As they prepare for the next stage in their lives they may be encountered hanging from the trees and shrubs on long silken threads. There is only one generation a year and the pupae remains dormant in the soil until the next adults emerge in the following spring.

Symptoms of these moth caterpillars----the leaves and young shoots are eaten in spring and early summer by the caterpillars. Characteristic irregular holes are eaten in leaves, often before they have expanded from the buds and those symptoms will persist throughout the growing season.

Extreme damage to fruit blossom and foliage may effect cropping and leaf damage on ornamental trees,shrubs and hedges make them look unsightly. persistent attacks weaken plants and facilitate the development of bacterial and other diseases.

Mottled Umber Erannis defoliaria

Source

caterpillar of the Mottled Umber

This quality image should help to identify this pest species.
This quality image should help to identify this pest species. | Source

Trees that are targeted by these caterpillars and some treatment ideas.

Among the many tree species that are targeted by these moths are apple, Pear, Plum and Cheriies, but also many ornamentals such as Cotoneaster,Hawthorn,Roses, Dogwoods, Sycamores and Willow may be badly affected.

A treatment for such attacks can help prevent severe damage or at least diminish it.You can protect valuable fruit and ornamental trees by applying a grease band to the trunk in September -October to stop the female crawling up the trunk to lay her eggs. It is advised that a specially formulated grease band is used available at garden centres,nurseries or online outlets.

Tie the band tightly onto the trunks after removing any loose bark. Care needs to be taken that the band is tightly fitted for any loose area will be exploited by the female moth.Also check any dead leaves or other plant debris does not get caught on the band or the female will use these as stepping stones to by pass the band and your efforts will have been in vein.

The grease should be directly applied to the trunk at the height of half a metre from the ground,make sure the grease forms a band of about six inches all around the trunk. Where grease bands can not be applied effectively,as for an example on shrubs or hedges,then, insecticides must be used especially on fruit trees,spray as soon as the buds have opened in spring,again ask for the right spray at garden centres, nurseries or on-line.

Codlin moth Cydia pomenella

Source

Larva of the Codlin moth

Source

The Codlin Moth Cydia pomonella

This moth ,as its common name suggests {Codlin being an old name for an apple} attacks apple trees. The caterpillars eat into the flesh of maturing apples making them inedible. While apples are the main target other trees may be utilized such as the Pear and other fruit trees. They produce similar symptoms as the Tortrix moth caterpillars {See below }, but the latter does not tunnel so extensively into the mature fruit.

The adults are active on warm nights in June and July,but they are small and inconspicuous. Females lay flat translucent eggs singly on fruits and leaves,and the caterpillars hatch in about two weeks. They immediately commence to tunnel into the fruit,often entering through the Calyx,so that there is no apparent entry hole.

These caterpillars in the space of a month will have eaten their way down to the core. After this time they leave the damaged fruit and commence to spin a cocoon,this may be behind loose bark,tree ties and other situations. Most caterpillars remain in their cocoon until the following season,but some pupate in August to produce a second generation in September .

Treatment,-- chemical control is not easy,since the timing is imperative to ensure young caterpillars are killed before they can tunnel into the fruits and effective spraying may only be possible on smaller trees. If this is possible spray apple trees after blossoming ,the first about mid June with a second application three weeks later.

A Fruit Tortrix moth Adoxophyes orana

Simon Hinkley and Ken Walker Museum Victoria.
Simon Hinkley and Ken Walker Museum Victoria. | Source

Fruit Tortrix moths

Here in the UK there are three species of Tortrix moth caterpillars that attack fruit trees. The Mining Tortrix,pammene rhediella, The Summer fruit Tortrix, Adoxophyes orana { pictured above} and the Fruti tree tiortrix Archips podana,{ pictured below} and all three produce similar symptoms.

The small inconspicuous adult moths fly at night during the summer. the females lay their eggs singly or in small bunches on the leaves. The resulting caterpillars immediately start to feed on the foliage. They are green and about 25 mm long. This feeding frenzy will last for about a month after which they will spin cocoons and pupate. A second generation of adults emerge inthe autumn and the young caterpillars that hatch from the eggs of this generation hibernate in cocoons on the infected plants. They become active again in the following spring and feed on young buds and leaves before pupating,to start the life cycle again.

The symptoms -the attacked fruits show various types of superficial scarring,distortion and tunnelling. Ripening apples are commonly affected. The caterpillars may be encountered on the damaged fruit and on the leaves and buds. The caterpillars spin silk to draw the leaves together into a protective covering ,and if these are opened carefully the caterpillars will characteristically wriggle in a backward direction as they are disturbed.

The damage these caterpillars cause is generally to unpredictable for chemical control to be effective. Sprays applied to control winter moths will give some incidental control of Tortrix moths,and if Tortrix moths are known to be particularly troublesome,a post blossom spray applied in Mid June with a second application a fortnight later will diminish damage to fruits.

For the Green oak moth see my hub Insects and oak trees.

There is a closely related species the Plum fruit moth Cydia funebrana that produces small white, pink or reddish caterpillars and causes similar damage.

Archips podana

Source

Magpie moth Abraxas grossulariata

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Caterpillar of the Magpie moth

Source

Magpie moth, Abroxas grossulariata

Adult moths are active at night in July and August,and the females lay their eggs, singly or in small batches on the underside of leaves. Caterpillars hatch about a fornight later and feed on the leaves in autumn.

The caterpillars are relatively small and over winter in cracked bark,leaf litter and similar situations and start to become active again in the following spring. This occurs from about April onwards. After feeding voraciously for a month or so ,conspicuous black and yellow banded pupae develop in the cocoons attached to the leaves and twigs of host plants or to fences,walls and other structures. Adults emerge from these in July and August to complete the cycle.

Black white and yellow 'looper' caterpillars up to 4 mm long and they eat the leaves of many plants species in April and June. Gooseberries and currants may be stripped of leaves and other plants such as Apricots,Crab Apples,Hazels,Laurels and Plums may also be chosen.

Treatment for these caterpillars. Look for them on host plants in early spring paying special attention to the center of Gooseberries and currant bushes, where attacks occur. remove the caterpillars by hand or spray with a contact insecticide


Caterpillar in 'Looper' position

Uploaded to Commons via Entomolo
Uploaded to Commons via Entomolo | Source

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10 comments

D.A.L. profile image

D.A.L. 20 months ago from Lancashire north west England Author

aviannovice,

Hi Deb, thank you so much for your kind comments and votes, much appreciated. Best wishes to you.


aviannovice profile image

aviannovice 20 months ago from Stillwater, OK

Such great information, especially about the grease band, which I had no knowledge until now. For this, I must give you an awesome and up.


D.A.L. profile image

D.A.L. 22 months ago from Lancashire north west England Author

Ericdieker,

Hi, thank you for your visit and for your kind comments. Best wishes to you.

prasetio30,

hi, your very welcome and thank you too for your kind comments. Best wishes to you.

Cat on a Soapbox,

Hi Cat; well spotted regards Monarch larva, I hope these beautiful butterflies recover their numbers. Thank you for your kind comments. Best wishes to you.

DDE,

hello Devika, Your kind and encouraging comments are much appreciated as are your votes. Best wishes to you..

Marina7,

hi, thank you your words are very kind and appreciated. Thank you,and best wishes to you.


Marina7 profile image

Marina7 22 months ago from Clarksville TN

So true and this is a great hub. I love the pics also.


DDE profile image

DDE 22 months ago from Dubrovnik, Croatia

A very interesting topic. You have shown the true meaning of life to these creatures. I have seen some on our plants especially when we planted broccoli this new season. Voted up, interesting, beautiful and useful.


Cat on a Soapbox 22 months ago

This is very helpful information, Dave. Here in California, the leaf-rolling larvae of the Tortrix moths present quite a problem because different species are often visually indistinguishable. Your lead picture features the caterpillar of the Monarch butterfly which is a beloved pollinator that feeds almost exclusively on the Asclepias plants. Its numbers are in rapid decline here in the West where we are encouraged to attract it to our home gardens. It is a pleasure to read your hubs, as always.

Best wishes to you this holiday season,

Cat:)


prasetio30 profile image

prasetio30 22 months ago from malang-indonesia

Very informative hub. Awesome pictures as well. Thanks for sharing!


prasetio30 profile image

prasetio30 22 months ago from malang-indonesia

Very informative hub. Awesome pictures as well. Thanks for sharing!


Ericdierker profile image

Ericdierker 22 months ago from Spring Valley, CA. U.S.A.

Very interesting and useful


Ericdierker profile image

Ericdierker 22 months ago from Spring Valley, CA. U.S.A.

Very interesting and useful

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