ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Oak-galls and Other Growths on Plants and Trees.

Updated on August 7, 2015

Notes from a Lancashire Countryman

As a plant enthusiast I pride myself at being able to look at a subject as opposed to seeing a subject. For example those of us that admire flora {whether wild or cultivated} will be in one or the other camps. Many will see a plant and admire its beauty, the flowers, foliage, colour and many will know the name of the plant they are admiring. To most this is enough and there is nothing wrong with that. Then there are those of us that look more deeply at the subject. For instance how many petals does the flower have? How many sepals?, stamens, anthers and so on? Are the leaves simple , divided, lobed ? etc etc.

Those of us that take this closer observation stance,, also observe many more subjects that occur in the natural world, such as insects, not only the conspicuous ones such as bees and butterflies, but the tiny invertebrates that need to be looked for on the foliage and flowers of flora including trees. During the course of my ramblings I encounter many weird and wonderful growths on various species of plants and trees and the tell tale signs of their work.

I suppose the most familiar of these growths are the galls which include Robin's pincushion. Galls on plants and trees are caused by insects and other organisms invading the plants tissues. So, what are galls? They are usually defined as being unusual or abnormal growths that provide food and security for the invading organisms. These parasites vary and may be fungi, bacteria insects and mites. A great majority {especially the common galls } are caused by insects. All parts of the subject invaded can be affected, the leaves, flowers, stems, roots and even seeds. However, each part that is affected is usually by one specialised invader.

The study of galls is called Cecidology from the Greek kekis meaning a gall. There are over 2,000 species in Britain, and more are discovered regularly. The Robins pincushion is probably the most conspicuous of the plant galls its colour attracting attention of the observant.

Robins pincushion

The Robin's pincushion is a wonderful structure
The Robin's pincushion is a wonderful structure | Source

Caused by a Gall wasp

They are usually encountered on wild roses and are formed by a Gall wasp, Diplolepsis rosoe, which lays eggs in the flower buds. Inside the weird structure there will be several tiny white grub. The normal development of the flower bud is changed by the chemicals secreted by the female laying her eggs and by the grubs themselves.

gall wasps are only tiny and only distantly related to the familiar yellow and black wasps so familiar to all of us. They are more ant sized than conventional wasp size and of a dark colour. Most of them are winged but some are wing-less.

Oak trees play host to many types of gall . There are two types that are more conspicuous than the others. One of these the Marble oak gall is produced by a gall wasp known as Andricus kollari. These are common and wide spread

Oak apple galls

oak apple galls  on the flowers of oak.
oak apple galls on the flowers of oak. | Source

Comparitively large galls

They are comparatively large galls, round and smooth, green or brown and woody up to 25mm across which develop from the buds after the female wasp lay her eggs in the spring. Each of these galls contain a single grub which feeds inside. The adults emerge through holes made in the gall during September and October. They may remain on the tree for many years.

Marble gall

Marble gall on oak.
Marble gall on oak. | Source

Oak apple gall

The oak apple gall caused by the wasp Biorhzza pallida is also common and wide spread and is often confused with the above species.These are slightly irregular, smooth galls that develop in the buds during spring. At first they are of a pale colour but quickly turn to red taking on the appearance of tiny apples. Within the galls interior there are several chambers that are occupied by grubs. The adults emerge in June and July.

Studies have revealed that females that emerge crawl down the trunk to lay their eggs on the roots. gall then occur on or in the roots. Within these galls larvae feed and over winter. Adults that emerge from these the following spring then make their back up to the buds to lat their eggs and the whole cycle continues.

Top Artichoke Gall. below. Red pea Gall

Artichoke gall is another species that may be found on oak and other trees such as the yew.
Artichoke gall is another species that may be found on oak and other trees such as the yew. | Source
Red pea gall is another species found on oak.
Red pea gall is another species found on oak. | Source

Leaf miner

Gardeners will be familiar with the classic signs of the Leaf Miner, discoloured markings on the surface of the leaf that portrays the movement of the larva inside the tissues as it munches its along. Chrysanthemums in particular and tomato foliage is often host to such larvae.

Tell tale signs of the Leaf Miner

Leaf miner larvae leave the tell tale signs of their presence.
Leaf miner larvae leave the tell tale signs of their presence. | Source

Sawfly galls

Sawflies can also contribute to the production of galls such as those found on the willow foliage. many species of saw fly of the genus Potania cause various leaf galls. These can be recognised as conspicuous hard red or green galls up to 2 cm long which develop on the foliage during the summer months. The larvae within the galls munch out cavities. A second generation emerge in October and over winter in cocoons on the bark or in the soil.

The most noticeable growth , particularly on birch trees, is commonly called Witches Broom. they consist of large clusters of growing twigs which give the impression of a large bird's nest or as the common name implies the base of a witches broom stick. These close growing twigs often have disfigured foliage. They can become extremely large and may eventually take up much of the crown. it is not fully understood what causes this growth but it is thought that fungal attacks are the main cause.

Witches Broom

The witches broom can appear as though there are large birds nests in the tree.
The witches broom can appear as though there are large birds nests in the tree. | Source

Gall flies

Gall Flies or gall midges of the family Cecidomyiidae are the most numerous of the gall causing flies. many of them have orange bodies and tiny wings. they may be observed swarming around street lights at night.

The lime gall mite Eriophyes tilliae produces a gall known as lime nail galls. they are small conical and red and appear on the upper surface of lime leaves. usually from May till June. A single leaf may bear hundreds of galls and their colour contrasts sharply with the green colour of the foliage. Sycamores and maples also endure attacks of nail gall mites. Readers might like to click on photographs to see larger images.

Gallery . Symptoms and signs of damage

Maple leaf gall is distinctive.
Maple leaf gall is distinctive. | Source
The damage done by the leaf miners can be mistaken for autumn colour on horse chestnut.
The damage done by the leaf miners can be mistaken for autumn colour on horse chestnut. | Source
The adult of the horse chestnut leaf miner.
The adult of the horse chestnut leaf miner. | Source
Close up of the knapper gall that disfigures acorns.
Close up of the knapper gall that disfigures acorns. | Source
FINALLY  GROWTH ON THIS ASH TREE
FINALLY GROWTH ON THIS ASH TREE | Source

Comments

    0 of 8192 characters used
    Post Comment

    • D.A.L. profile image
      Author

      Dave 7 years ago from Lancashire north west England

      Hi Nell, your welcome. Nice to see you here. Best wishes to you.

    • Nell Rose profile image

      Nell Rose 7 years ago from England

      Hi, the Robins pincushion! what a great name! fascinating, I had never really looked before, but I will keep my eyes open now,and I never knew they were called galls, thanks nell

    • D.A.L. profile image
      Author

      Dave 7 years ago from Lancashire north west England

      Hi, Carol, they are fascinating things. Over 2,000 are known to exist in Britain and it is thought there is many yet to be discovered. Thank you for visiting . Best wishes to you.

    • reddog1027 profile image

      reddog1027 7 years ago from Atlanta, GA

      I always learn something new from your hubs D.A.L. I didn't know there were so many different and interesting types of galls.

    • D.A.L. profile image
      Author

      Dave 7 years ago from Lancashire north west England

      Hi thoughtforce, nice to meet you. Thank you for reading glad you found the hub useful. Your kind comments are appreciated. Best wishes to you.

      Hi, DREAM ON,glad to have been of hel;p. Thank you for reading and for your appreciated comments. Best wishes to you.

    • DREAM ON profile image

      DREAM ON 7 years ago

      I never looked at plants so close before.You opened my eyes.

    • thougtforce profile image

      Christina Lornemark 7 years ago from Sweden

      I think the pictures are beautiful even if it is galls! It is amazing that even such a thing can look so different! Escpecially the knapper gall is remarkable! And I found this hub useful to, now I know what I see if I find some of them!

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: "https://hubpages.com/privacy-policy#gdpr"

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)