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Dutch Elm disease and Brighton’s National Collection of elm trees

Dutch Elm disease and Brighton’s National Collection of elm trees

by Oliver ~ 23 June, 2013 ~ 3 comments

Brighton in Sussex is home to Britain’s largest population of Elm trees. These 19,000 elm trees are known as The National Collection. Elm trees are increasingly rare due to the blight brought by Dutch Elm disease principally in the 1970s.  Initially this came into the UK as long ago as 1926.  Dutch Elm disease is a fungus carried by beetles and affects only elm trees. In response to this attack, an elm tree will automatically produce tyloses, an effective natural defence against the 1926 strain of Dutch Elm disease. Tyloses occur in the xylem – water conducting vessels of the plant / tree, sealing them off and restricting the movement of the pathogen.

However in the early 1970’s,  a new strain of Dutch Elm disease was imported from channel ports, linked directly to the Canadian Rock Elm. This strain travels faster through the elm trees and kills them before they can produce tyloses. Since the introduction of this strain of Dutch Elm disease to Britain, the number of elm trees has gone down from about 3 million to fewer than 200,000 and many of these are very young ones which will certainly succumb to the disease. Elm trees reproduce by root stalks more often than by seed and so this transmission mechanism quickly spreads the disease between elm trees and along elm hedgerows. Read more…

Warfare amongst the ladybirds.

Warfare amongst the ladybirds.

by Lewis ~ 17 May, 2013 ~ one comment

The asian or harlequin ladybird was used in commercial glasshouses / greenhouses to control aphids (greenfly / blackfly) – a single harlequin ladybird can eat up to 200 aphids a day.  Unfortunately, some of the harlequin ladybirds escaped and their offspring have spread across Europe – endangering native species.

Recent research has shown that this invasive species has an impressive immune system – the body fluids of this animal contain a strong antibiotic compound (HARMONINE) and also small proteins (peptides) that have anti-microbial properties. Read more…

Invasives and aliens - PlantTracker app.

Invasives and aliens – PlantTracker app.

by Chris ~ 31 January, 2013 ~ Comments Off

Some plants, like the Himalayan Balsam, Japanese Knotweed and Giant Hogweed are spreading across the country.   Giant Hogweed, also known as wild rhubarb, giant cow parsnip or giant cow parsley is a dangerous plant.  It was introduced as an ornamental plant in the C19th; it is however – phototoxic.  If the sap gets on the skin then photodermatitis occurs – causing blistering of the skin and scarring, and minute amounts in the eyes can cause blindness.

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Invasive non-native spacies can displace native species, altering the ecology of various habitats; they might be described as ‘botanical thugs’. One single hogweed plant is capable of producing 80,000 seeds.  Once established the removal of these plants can be expensive and time consuming.  The earlier an ‘outbreak’ or invasion by one of these plants is reported, the easier it is to deal with. Read more…

Bracken Control

Bracken Control

by Nick Burton ~ 7 January, 2013 ~ 2 comments

On 1 January 2013 it will become illegal to use the bracken-control chemical Asulam.  The chemical, which was sold as Asulox, was banned by the EU on 31 December 2011 but those who already had stocks had a year to use these up. While good in small areas, as it provides cover for animals, bracken can be a real problem, quickly becoming a monoculture, shading out and eliminating wild plants and flowers.

Landowners are now considering their options, Read more…

Ash dieback - what to do?  Pre-empt, plant, persevere, keep calm and carry on.

Ash dieback – what to do? Pre-empt, plant, persevere, keep calm and carry on.

by Richard ~ 30 October, 2012 ~ 5 comments

The last ice age endured for about 100,000 yrs.  Some 18,000 yrs ago, mammoths, sabre-toothed tiger and woolly rhino (preyed on by prehistoric man) roamed our land.  Thick ice sheets lay to the North, whilst to the South was tundra – much like that now seen in Northern Siberia. Then 10,000 years later, the ice sheets started to melt and the tundra receded; sea levels rose and low lying areas were flooded.   The North Sea and English Channel formed, cutting us off from mainland Europe. This was a gradual process (in our terms) and as Europe warmed,  trees migrated northwards – some reaching the UK before we were cut off from the rest of Europe.  Most plant colonisation was by seed and spores, animals followed bringing with them other taxa. Read more…

Horse chestnut leaf miner moth - help needed

Horse chestnut leaf miner moth – help needed

by Lewis ~ 11 September, 2012 ~ 5 comments

The leaf miner moth (Cameraria ohridella) that arrived in the UK about a decade ago has spread widely, and many horse chestnut trees have been ravaged by its activities (see related posts / links). The brown, lifeless leaves that dangle from the branches in late summer are a clear sign of the activities of this insect.  It had been hoped that certain parasitoid wasps might help control the leaf miner, but this is not the case. There is now the suggestion that birds, like blue tits, might help.

Read more…

The harlequin ladybird

The harlequin ladybird

by Chris ~ 18 March, 2012 ~ one comment

Some six years ago, there was a post about the harlequin ladybird  (Harmonium axyridis)– aka Multicoloured Asian Ladybird and the Halloween Ladybird – a ‘newcomer’ to these isles, and which might prove to be a threat to the native species.  The harlequin ladybird in an Asian species that has been used for pest control (aphids etc).  All ladybirds are beetles.  They belong to the order – Coleoptera – and are characterized by having forewings modified as hard wing covers or ELYTRA and biting mouthparts (cf. butterflies and moths).

Now some years later, research by scientists at the Centre for Ecology and Hydrology have evidence of strong link between the arrival of the harlequin ladybird and the decline in other species of ladybirds.  Seven out of the eight native british species have declined – with some now described as being ‘near the threshold of detection’; similar issues have arisen in Belgium and Switzerland where the harlequin ladybird is also present. Read more…

Signal Crayfish

Signal Crayfish

by Lewis ~ 2 March, 2012 ~ 2 comments

Plants and animals from different parts of the world are being ‘mixed’ up as worldwide travel by train, boat and plane increases year by year.  The woodlands’ blog has reported on a number of plants and animals that are regarded as ‘aliens’ or invasive species, for example, the ‘killer shrimp’.  Sometimes the ‘concern’ proves to be unfounded, but the arrival of various pathogens can be problematical for ‘native species’.

At some point back in the 1970’s, the North American signal crayfish arrived in the U.K.   Since that time it has spread through various river systems, particularly in South and South East England, at the rate of 2 km per year (approx.).   Its spread may have been assisted by damp fishing gear.  It would seem that the signal crayfish is out-competing the native white clawed crayfish (that is, native to Europe, including England, Wales and Ireland – but not Scotland). Read more…

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