Additional Notes:Welcome to the Tree Health Survey Training session.House keeping notices for venue.General information on this presentation:Each slide is accompanied with notes to augment the information presented. These are split up into Slide Comments (information to be given to the audience), Image Details (If you or the audience would like to know what they are showing) and Additional Notes (Background information for the presenter).Photographs are sourced from Forest Research, Forestry Commission or Fera. Known photographers are documented in the notes section.! Please note that the OPAL magnifying glass indicates the identifying features of the pest / disease and the blue box indicates the presence in the UK. Red boxes will indicate where there is risk to human health.
Slide Comments:The training structure.Introduction to UK forests and Tree HealthThe Value of Trees Tree HealthThe OPAL SurveyPests and DiseasesIntroduction Why Study These Pests and Diseases?Specific Pests and DiseasesConducting the surveyBefore You Start How to do the ActivitiesSubmitting Data and ResultsPractical TrainingExplore outsideTimings and breaks…
Slide Comments:The first section: and introduction to trees and tree health…
Slide Comments:The second section: an introduction to pests and diseases…! Please note that the OPAL magnifying glass indicates the identifying features of the pest / disease and the blue box indicates the presence in the UK. Red boxes will indicate where there is risk to human health.It may be useful to provide a short introduction to the Twelve Common Pests and Diseases that affect Oak, Ash and Horse Chestnut…i.e. looking in more detail at four pests and diseases that commonly affect each tree species. The first of which is the knopper gall…
Slide Comments:Monitoring pests and diseases affecting Britain’s trees aids our understanding of their impact, their changing distribution and helps to manage their spread. Answers questions about whether levels of damage caused by specific pests and diseases are becoming more or less severeIdentifies the extent to which specific trees or tree species are being affected by multiple pests and diseasesNeatly show different ways to display data. Can collect data on the presence absence of diseases and the severity. These images demonstrate the spread of the diseases, and in the case of Chalara, the origin. This is why we need to monitor pests and diseases i.e. the purpose of this Survey.NB: Chalara map not up to date, should show 2012 for UK. Image Details:Chalara: The spread of Chalara across EuropeLeaf Miner: The spread of the miner across the UK. The latest HC leaf miner map is the 2010 one though Nigel Straw is currently working on the new maps.Additional Information:From Survey PackCollecting information on the pests and diseases affecting Britain’s trees helps scientists find out more about changes in their effects or distribution. This information will help answer questions about whether levels of damage caused by specific pests and diseases are becoming more or less severe. It will also help researchers identify the extent to which specific trees or tree species are being affected by multiple pests and diseases. Sometimes pests and diseases that would only cause minor damage in a healthy tree can act together, making it weak and vulnerable and even tipping it into decline.Background information on pests and diseases affecting Oak, Ash and Horse Chestnut..OaksOur native oaks, known as English Oak (Quercusrobur) and Sessile Oak (Quercuspetraea), arethe most common broadleaved tree. Some of the oldest are over 100 years old. Native oakpopulations suffer from a number of pests and diseases. Usually the effects are temporary andthe trees soon return to full health. However, if an individual tree is seriously damaged for severalyears in a row, it can initiate a disorder known as ‘oak decline’. In this weakened state, oaks maythen be attacked by other organisms that would not usually bother a healthy tree, but may contribute to oak decline and eventually cause its death.AshIn Britain, Ash (Fraxinus excelsior) is the third most common broadleaved species (after Oak andBirch) and is a native species that is widespread throughout woodlands and hedgerows. Theclusters of ash fruits are known as ‘keys’ and often remain hanging on the trees after leaf fall inautumn.Ash can suffer from a variety of root and trunk rots that can cause late flushing (opening ofleaves in spring), thinning foliage and decline.However, very recently, a new and often fatal disease Ash Dieback, has been found in Britain.This disease has become widespread in mainland Europe over the past two decades.Horse Chestnut Horse Chestnut (Aesculushippocastanum) is native to south-east Europe, but was introduced into Britain over 300 years ago.Its striking creamy white flowers appear in early June and provide pollen for many insects. The characteristic fruits (conkers) are produced in September.Over recent years a number of pests and diseases have affected horse chestnut. Most of these are relatively recent arrivals in Britain but have spread steadily through horse chestnut populations and can be very damaging.
Slide Comments:! Please note that the OPAL magnifying glass indicates the identifying features of the pest / disease and the blue box indicates the presence in the UK. Red boxes will indicate where there is risk to human health.Pest summary:Knopper Gall can be very common in some years and so reduces the level of regeneration. The galls on acorns are from the second generation of the wasp. The first generation causes currant galls of the flowers of Turkey oak.Image Details:Knopper gall: Photograph courtesy of Nigel Straw, Forest ResearchAdditional Information:From Forest Research Expert: This is a very common pest symptom. It looks as if the acorns were made out of plastic and have melted. They are greasy in appearance.This symptom is the second stage of infection: at first these wasps reside on Turkey Oak (creating current galls) and then move to English Oak to create the knopper gall. From SurveyKnopper galls are caused by a tiny gall wasp called Andricusquercuscalicis. If you cut open the gall, you should see the white wasp grub (larva). The wasps arrived in southern England in the1950s and have now invaded most of the UK. The wasp does not kill the tree, but affected acorns cannot germinate.It produces ridged outgrowths on the acorns of native (pedunculate) oaks; forming in August they are sticky and red, later becoming woody and brown. Does not kill tree but affected acorns cannot germinate
Slide Comments:Pest Summary:Tortrix roller moth: A serious defoliator of oak but severe outbreaks are cyclical, usually 4 to 5 years apart. Defoliated trees will re- foliate in the same year but repeated severe defoliation can weaken the tree and contribute to oak decline.Other common oak defoliators include OperophterabrumataandErannisdefoliaria. Generally damage is not as severeImage Details:Left: Adult which is occasionally seen.(Photos courtesy of Nigel Straw, Forest Research)Middle: Large olive brown caterpillar.(Photos courtesy of Nigel Straw, Forest Research)Right: Leaf rolls created by tortrix(From ‘Insect Images’ under the Creative Commons licencePhotographer Information: Name: PetrKapitola:Organization: State PhytosanitaryAdministration:Country: Czechia)Additional Information:From Forest Research Expert:- The key ID feature is the rolled leaves.- Creates such devastation that you can walk into a wood in July and it looks like winter. Oaks can re-foliate up to three times in a season, but the tree expends a lot of energy doing so.A trick for testing if it’s a roller moth is to pole the caterpillar and it will always move backwards.From Survey PackThe roller moth, Tortrixviridana, is a native species of micromoth. The moth caterpillars feed on tender new leaves. Heavily infested trees can be completely defoliated. (lose their leaves), affecting the tree’s ability to photosynthesise. When the caterpillars pupate (become an adult moth), they roll the leaf edges around themselves, hence the name ‘roller’ moth. Oak is generally very resilient to defoliation. Single defoliations generally have limited effect on growth and no long-term effect on tree health. Severe defoliation repeated over several years appears, especially in association with drought, to be a pre- disposing factor that can lead to oak decline.From Forestry Commission Website:Most notable among the early season defoliators are oak leaf roller moth Tortrixviridana (below left) and winter moth Operophterabrumata (below right). Both species have egg hatch time to coincide with bud burst in the spring and the young larvae feed on the newly expanding leaves. When numbers are high, complete defoliation of trees can occur, but a second flush of leaves later in the season partially offsets the negative effect on trees. However, it is likely that severe defoliation does reduce the ability of trees to defend themselves from attack by other agents.More information at: http://www.forestry.gov.uk/fr/infd-7b3d8v
Slide Comments:Disease Summary:Oak mildew: Widespread disease that varies in severity according to weather conditions in a particular year. Not in itself very damaging but is part of the oak decline syndrome.Image Details:Top: Silvery appearance on leavesBottom: Close up of mildewAdditional Information:From Forest Research Expert:- People often describe the leaves as silvery in appearance.- Can get blackening effect and leaves shrivel- There are two infection periods, most people usually see summer one. It most typically affects the second flush of leaves on oak (known as lammas growth, produced in July and August). If the first set of leaves have been affected by tortrix, then a mildew attack on the second leaf flush can be very debilitating , especially if it happens several years in succession. - Buds with mildew are often more sensitive to low temperatures. The White growth of powdery mildews makes them one of the most easily recognised fungal diseases. Whilst powdery mildews will rarely kill a plants, it will cause a loss of vigour and may lead to decline.There are many different species of powdery mildew, but they have a fairly limited host range, often affecting plants from just one family. The powdery mildew that infects Oaks will only infect Oaks, although you may see other powdery mildews on other plants in the same area they will be different species.The majority of the growth of most powdery mildews is present on the surface of the plant.Powdery mildew symptoms consist of white or of white fungal growth on surfaces mainly young leaves and stems. The growth consists of mycelium (felty) and asexual spores (powdery appearance). It is usually most powdery when the humidity is high large numbers of spores are produced. The fungus may also produce sexual spores within a brown or black, pin headed sized fungal fruiting body which is found amongst the mildew growth later in the season. It plays an important role in overwintering. Powdery mildews are obligate parasites meaning that they require living host tissue on which to grow. The asexual spores of powdery mildews are often produced in huge numbers (many thousands on a single leaf) and are readily dispersed by air currents, water splash, etc. The symptoms of powdery mildew of oak is very obvious and characteristic and is easily identifiable in the field. It may be possible to confuse it with other point leaf deposits such as lime scale, pesticides or even bird droppings! However, the powdery nature of the spores is very characteristic-you can demonstrate superficial nature of the fungus by placing a piece of sticky tape on the upper surface of the leaf and pulling it off carefully leaving behind an otherwise green leaf.The powdery mildew usually colonises younger leaves on shaded stems-it is interesting to note that older leaves or stems in full sunshine may not be infected even though other parts of the tree are covered in powdery mildew.
Slide Comments:Pest Summary:Ash bud moth: Destroys or damages buds, especially the terminal buds, causing poor flushing or wilting of partially flushed leaves. Attacks are cyclical and severe damage can exacerbate ash decline.Image Details:Top: Canopy thinningBottom Left: Terminal apex wiltingBottom Right: Lateral apex wilting(Photos courtesy of Robert Strouts, Forest Research)Additional Information:From Forest Research ExpertAsh has always had pests and diseases,Chalarais not the first.Can be confused with the early stages of Chalara.This is a cyclical problemIf a fungus enters the wound can kill the whole shoot. From survey:The ash bud moth Prays fraxinella, is a native species of micromoth. The moth caterpillars feed on Ash leaves and make tunnels in ash buds or in the bark at the base of new shoots. If holes aremined in the base of the bud, the leaf shoots may either fail to flush (grow) or may flush but then wilt and blacken. You may also be see caterpillars’ entrance/exit holes, and silken webs. Symptoms aremost obvious on younger trees.
Slide Comments: Pest Summary:Ash key gall/Cauliflower gall: limited effect on the tree though it can restrict seed dispersal.Image Details:- Ash key gall attached to stemAdditional Information:From Forest Research Expert:Very common, are likely to see many galls and this indicates a healthy tree (as mites prefer health trees). From SurveyAsh key galls are caused by the mite Aceriafraxinivorus. The crusty galls are green at first, but later become brown. Older galls can remain attached for over a year, so they stay visible all year round.The galls make ash keys heavier, so wind dispersal is hindered and the seeds are not carried as far.From Forest ResearchSymptoms are caused by a mite that causes tremendous proliferation of flower buds on male ash trees.Eriophyid mites on very small and less than 0.5 mm long and may easily be overlooked, they may be seen with a magnifying glass but even then this can be quite difficult.
Slide Comments:Disease Summary:Nectria canker: Large cankers on branches or stems can lead to breakage. Even where this does not occur the timber value, in the case of stem cankers, is severely reduced.Image Details:- Top: Close up of canker- Middle: concentric rings of canker about 25 years old caused by this fungus on the main stem of an ash.- Canker along stemAdditional Information:From Forest Research Experts: A key identification point: the canker looks as if someone has pushed their thumb into plasterscene. Thenectria canker will only appear on one side of the trunk whereas a bacterial canker will spread around the circumference of the trunk at look rough in appearance.It will leave a scar.Susceptibility is geneticFrom surveyNectria canker is caused by the fungus Neonectriagalligena. It is a native disease which may be linked to existing wounds and cancause branches to break. The canker (patch of dead or infected wood) usually has a small side branch or wound at its centre.Cankers are smooth or ridged, rather than gnarled or knobbly. In the autumn you may see the fungal fruiting bodies – small(1-2 mm) orange-red spheres or dots at the edge of the canker.From Forest ResearchNeonectriagalligena (Nectriagalligena) causes perennial cankers and dieback of various broadleaved trees in temperate regions around the world. The fungus has a very broad host range affecting amenity, Forest and orchard trees (it is a very common problem on apple trees for example).SymptomsLesions first appear as small, dark, depressed areas on young smooth barked stems and they often kill twigs by girdling them. Most cankers are centred on small branch stubs or their remains, and disease trees he usually have more than one canker. Cankers on most hosts become perennial and target shaped. They expand slowly, usually during host dormancy, and often less than 1 cm in year. During the growing season callous and woundwood form around the region.Bright red or reddish orange lemon shaped fungal fruiting bodies left the 0.5 mm in diameter develop in autumn to spring on dead bark. They form singly or in groups on young cankers still covered with bark or on woundwood.The fungus overwinters as sexual fruiting bodies and mycelium in dead bark. Sexual spores are expelled from fruiting bodies and dispersed by wind or water any time of the year during rain or moist periods its primarily in spring and autumn.Middle Photo: Perennial ' target ' canker about 25 years old caused by this fungus on the main stem of an ash.
Slide Comments:Summary:Ash decline: A progressive decline over a number of years which dieback mainly starting in the upper crown. The dieback allows the entry of decay fungi causing loss of timber value and creating a safety hazard for trees in public places and along roadsides and paths.Image Details:Ash decline in canopyAdditional Information:From Forest Research Expert:Can result in the death of a major part of the crownBecause it is progressive, will need to be monitored over a number of years.From Survey:Ash decline is caused by a combination of factors that affect the roots and causes a gradual decline in the tree. It is common in hedgerow trees beside ploughed fields, especially on drier sites. Check the symptoms for Chalara dieback of Ash in the Most Unwanted Guide before diagnosing Ash decline.FromForestResearch:Ash decline is a long known disorder, which has been around much longer than Chalara ash dieback. Typically trees affected by ash decline are found where there is likely to have been root damage (e.g. edge of ploughed field) or on drier sites. Often a combination of physical and biological factors have casued the deline.
Slide Comments:Disease SummaryHorse chestnut leaf blotch: A disfiguring condition that is often linked to wet weather in mid-summer. Not considered to be a major problem but there may be interactions with other problems on horse chestnut.Image Details:- Top: Blotch on leafBottom: Fruiting bodies on underside of leafAdditional Information:From Forest Research Expert:- Yellow outline is diagnostic.- Appears in June- It is distinctive and easy to identifyFrom Survey:Caused by the fungus Guignardiaaesculi, this disease was first reported in Britain in 1935. Blotches are on the leaf tips and edges, and you may also see tiny black dots in the blotches. Sometimes the whole leaf turns brown and shrivels. Leaf blotch is considered disfiguring rather than damaging. Look carefully, as leaf blotch can be present when Horse Chestnut Leaf-miner is also present.From Forestry CommissionGuignardiaaesculi is a fungal foliar pathogen. Symptoms first appear as water soaked irregular areas that enlarge rapidly. Within a few days they turn reddish brown to black common often bordered by a yellow band that emerges gradually with green tissue (leaf miner lesions are more clearly defined and are see-through). Small lesions may be limited by veins, larger lesions often coalesce and cause distortion and partial shrivelling of leaflets. Severe disease causes premature defoliation.The fungus produces black fruiting bodies less than 0.2 millimetres with in the necrotic spots that can be seen erupting through the upper leaf surface, they will be visible using a magnifying glass or hand lens.The fungus over until fallen leaves and spores are released in early spring into the air during wet weather while leaf are developing. Symptoms develop within 2 to 3 weeks of infection. Infection may occur during the season leading to the rapid buildup of symptoms.
See Previous two slides for Slide Comments and Additional Information.Image Details:White= blotchesRed or brown blotches are on the leaf tips and edgesoften outlined in yellowHold the leaf up to the light, blotches are NOT see-throughBlue= Leaf-minerBrown blotches on the upper or lower surface of the leafHold leaf up to the light, blotches ARE see-through and can usually see larvae in mines.
Slide Comments:Disease Summary:Bleeding canker of horse chestnut: An introduced disease that causes damage, often severe and resulting in death of the tree, that has spread rapidly. Changes in levels of infection are important to understand its likely long-term impact.Image Details:- Top: Trunk with bleeding cankerBottom: Close up of canker oozing and rusty liquid.Additional NotesFrom Forest Research Expert:Has had a large impact in the nursery sector90% likely to be bacterium. Bleeding is caused by the living organism attacking the treeTypical case of an introduced pest, exponential increase when brought in but cases now in decline, 53% are resistant to the canker.From Survey:Caused by the bacterium Pseudomonas syringaepathovaraesculi, this disease suddenly appeared in the early 2000s. It attacks and kills the bark of infected trees. The bark is often cracked and disrupted. Severely affected trees have thinning crowns with dead branches, and ultimately the tree can die if the infection is very severe.From Forestry Commission website:Incidence of the diseaseGeographical location of cases of Horse Chestnut Bleeding Canker reported to Forest Research Disease Diagnosis Advisory ServiceUntil recently, such Phytophthorableeding cankers were considered to be uncommon and were only seen in the south of England (Strouts and Winter, 2000). However, over the past four or five years, the number of reports of horse chestnut trees (Aesculushippocastanum) with 'bleeding cankers' has increased markedly. Symptoms visible on the heavily affected trees include extensive bleeding areas on their stems and sometimes on their scaffold branches. The increased incidence of stem bleeding on horse chestnut is not just limited to the UK; the Netherlands, Belgium, France and Germany are also experiencing a similar upsurge.Closer investigation of the bleeding cankers on horse chestnut has revealed that Phytophthora is no longer the primary causal agent. Instead a completely different pathogen, Pseudomonas syringae pv aesculi, is responsible for the increase in these symptoms appearing on horse chestnut.Over the past four years the Tree Health Diagnostic and Advisory Service of Forest Research has received increasing numbers of reports about the disease. In 2000 only four reports had been received but by 2003 more than 60 reports of stem bleeding in horse chestnut were recorded. In 2004, 90 reports were received, around 75 in 2005, and more than 110 in 2006. Affected trees have been recorded as far north as Lancashire, Glasgow and Fife.What trees are affected?Trees of all ages have been affected by the recent disease upsurge. Young trees with a stem diameter of only 10cm (4 inches) have been found with advanced symptoms. However, the impact on the environment can be particularly profound when large, mature trees are infected and disfigured by the disease. If the disease is severe and the areas of bark which are killed are extensive, large trees can undoubtedly be killed. However, younger trees (10-30 years old) are at greater risk and can succumb to the disease in just a few years (3-5) as the smaller diameter of their trunks means that they can be girdled more quickly.pathogen known as Phytophthora (Brasier and Strouts,1976). The same disorder had also been recognised in the USA much earlier in the 1930’s (Caroselli, 1953).More information can be found at: http://www.forestry.gov.uk/website/forestresearch.nsf/ByUnique/INFD-6KYBGV
Slide Comments:Pest Summary:Horse chestnut scale: Another introduced pest that is found on other species of broadleaves as well as horse chestnut. Not damaging in itself but may be a problem in combination with other pests and diseasesAdditional Information:From Forest Research Expert:Can easily see the brown carapace of the dead females atop of the white egg case. When young emerge, head up trunk to feed on the leaves and female adults come back down the trunk to lay eggs. Identification feature: Tree looks leprous. From SurveyIn May or June, the adult female produces a white woolly ovisac (egg capsule) into which she lays hundreds of eggs. She dies after laying, but remains attached to the ovisac.The white ovisacs could be mistaken for bird droppings, and although they disfigure the tree, they do not kill it.From the Forestry Commission Website:Horse chestnut scale, apparent as circular white spots on trunks or large branches (and sometimes mistaken for pigeon droppings), is caused by the insect Pulvinariaregalis. This insect pest is occasionally found disfiguring trees in urban localities.
Slide Comments:Moving on to the Six Most Unwanted…
Slide Comments:All noted on slide.Image Details:Top Left: leaf wilting (Photo courtesy of Thomas Kirisits)Top Middle: Lesion (Photo courtesy of Thomas Kirisits)Top Right: Lesion (Photo courtesy of Thomas Kirisits)Bottom Left: Leaf browning (Image courtesy of I Thomsen and L McKinney) Bottom Right: Fruiting bodies (Image courtesy of I Thomsen and L McKinney) Additional Information:From Forest Research Expert:- There was a press release in October 2012 for the outbreak of Chalara and in December 4064 cases were reported (only half of which were positive cases)This research is supporting the official surveillance of Chalarafraxinea. In Nov 2012 a week long snapshot study was conducted over 10 km grid squares to establish the distribution. This Survey will follow up on this research 6 months on.At present the pathogen is found in wild trees only East of the M1, would be useful to know if it has spread West.From Survey:Already infected a large number of Ash trees across continental Europe, with a significant loss of trees anticipated in the next 20 years • First found in Britain in 2012• At time of press, there is a ban on imports and movement of AshWhy will any findings be important?• Knowledge about the distribution and extent of Chalara dieback of Ash• Knowing exactly where it is will help us to manage the spread of this diseaseFrom:ObservaTreeRealisation that a pathogen was involved came in early 2000scausal agent (Chalarafraxinea) named in 2006 other name – Hymenoscyphuspseudoalbidus in 2010Early impact Poland, Lithuania, then Scandinavian countriesSome countries 60-90% ash affected eg DenmarkDespite impact & spread not designated as quarantine organismHow did it arrive in the UK?Long distance movement: evidence this has occurred via plant trade. Disease has been found in nurseries in a number of European countriesLocal spread: wind borne spores. Evidence that at epidemic fronts (eg Norway) disease can move 20-30km per year Recent evidence of seed-borne disease, has been detected in seeds collected from symptomatic treesNot all ash species equally susceptibleMore information available on FC website http://www.forestry.gov.uk/chalara
Slide Comments:All noted on slide.Image Details:Top Left: D shaped holesTop Right:serpentine minesBottom Left: The beetleBottom Right: Fissures, natural callus formationAdditional Information:From Forestry Research Expert:This devastates trees, on the scale of the dutch elm diseaseIt is currently in Moscow, Russia and is currently spreading West. Could potentially arrive in the UK therefore want to know about these asap.From Forestry CommissionWebsite:Agrilis beetles are known as jewel beetles because of their bright colours. The Agrilis that attacks ash is related to the Agrilis that is found on oaks suffering from oak decline. However, whereas the oak Agrilis only attacks weakened trees-i.e. not a killer in its own right, the emerald ash border can attack health trees, thereby causing their deaths.An exotic beetle pest that causes signiﬁcant damage to ash trees (Fraxinus spp.)What to look for:* Initial thinning or yellowing of the foliage (general or limited to certain branches).*Bark ﬁssures, 5-10cms in length, caused by the growth of callus tissue produced by the tree in response to larval feeding. * Woodpecker activity. Woodpeckers strip away small patches of bark, so that they can extract the borers.* Larval galleries. Typical galleries meander, bending sharply and are packed with frass.* D-shaped holes, abou3 mm in diameter, produced by emerging adults. The SymptomsEAB infestations are usually difﬁcult to detect until the symptoms become severe. Trees exhibit a general yellowing and thinning of foliage, dying branches and crown dieback, typically from the top down. Small trees can be killed in one year, but larger trees can take up to 4 years to die. Sprouting epicormic shoots, small longitudinal splits in the bark or woodpecker activity may indicate beetle presence. Characteristic serpentine insect galleries can be exposed when pieces of bark fall from damaged trees that have been infested for 1 to 2 years.Life Cycle of EABIn China the beetle develops through its full life cycle in one year over most of its range and this appears to also be the case in North America. In colder northern areas of China the cycle can take two years.The ThreatAsh is an important broadleaf tree in the UK, the second most commonly planted genus, and makes up nearly 15% of all broad-leaved woodlands. Its wood is strong with many uses including the manufacture of ladders, ﬂooring, handles, sports goods and furniture.Although there is no evidence to date that the emerald ash borer is present in the UK, the increase in global movement of imported wood, wood packaging and dannage poses a signiﬁcant risk of its accidental introduction.In the UK, ash trees can suffer from a variety of root and butt rots that can cause late ﬂushing, thinning foliage and decline leading to eventual death, symptoms similar to those caused by the emerald ash borer. F. excelsior can also suffer from a condition called Ash dieback, involving the death of scattered twigs, branches or limbs, especially in the eastern drier parts of the country. Although not fully understood, this may be partially due to root disturbance. Trees with symptoms like these that also show any signs of infestation by the emerald ash borer should be reported immediately.More information can be found at: http://www.forestry.gov.uk/pdf/epa_emerald_ash_borer.pdf/$FILE/epa_emerald_ash_borer.pdf
Slide Comments:All noted on slide.Image DetailsTop: The caterpillarsFrom Left-Caterpillar nestCaterpillar defoliationCaterpillar hairs up close - Symptom of human health problemsAdditional Notes:From Forest Research Expert:Well established in LondonThere was a successful attempt to eradicate the caterpillars in Berkshire. This pest demonstrates the dangers of importing large trees from abroad. They came into West London on large Oak trees from the Netherlands.Native to central and Southern Europe and moving North (potentially due to climate change). Because they are moving into new environments, they pose a greater threat.There are some good You Tube clips available online.From the Forestry Commission WebsiteThe larvae, or caterpillars, of Oak processionary moth (Thaumetopoeaprocessionea, OPM) are a pest because they pose a threat to oak trees and to human and animal health. Introduced on 4-8 m tall imported oak for street landscape plantingsMajor oak defoliator - caterpillars feed on many species, including English, sessile and Turkey oak The threatOPM caterpillars can threaten the health of oak trees because they feed on the leaves. Large populations can strip whole oak trees bare of leaves, leaving them vulnerable to attack by other pests and diseases, and less able to withstand adverse environmental factors such as drought and flood.The caterpillars have thousands of tiny hairs contain an urticating, or irritating, substance called thaumetopoein, from which the species derives part of its scientific name. Contact with the hairs can cause itching skin rashes and, less commonly, sore throats, breathing difficulties and eye problems. This can happen if people or animals touch the caterpillars or their nests, or if the hairs are blown about by the wind.Outbreak stageThere are three confirmed outbreaks of breeding OPM in Great Britain, all of them in southern England:• several boroughs in West and South-West London (discovered 2006)• Bromley and Croydon Boroughs in South London (2012)• Pangbourne in West Berkshire (2010)It is no longer possible to eradicate the West and South-West London outbreak, but FC and our partners are working hard to minimise its population, spread and impact as much as possible.Managing affected treesFC advise people not to try to remove OPM caterpillars or nest themselves because of the health risks, and because to be most effective the job should be carefully timed and carried out by professionals with appropriate training and equipment. Report the presence of the pest to your , and get a professional pest control operator to remove the infestations. Your local council or our Plant Health Service can provide details of suitable pest control operators working in the area.
Slide Comments:All noted on slide.Image Details:Top: Tent like nests of caterpillarsBottom: CaterpillarAdditional Information:From Forest Research Expert:Early sightings are useful to controlCurrently just across the Channel in Normandy and Brittany, not strong fliers but they could get carried across in the wind. From the Forestry Commission WebsitePine processionary moth (PPM) is a tree and forestry pest because its larvae, or caterpillars, feed on the needles of pine trees and some other conifer tree species. In large numbers they can severely defoliate trees, weakening them and making them more susceptible to attack by other pests or diseases, or to environmental stress caused by drought or excessive moisture.PPM Is extending its range across Europe towards the English Channel- A transient population of caterpillars was found in the UK Nursery in 1995 on Scots pine plants imported from Italy.PPM, like its close relative the oak processionary moth (OPM), gets its name from its distinctive habit of moving about in nose-to-tail processions.Also like OPM, PPM caterpillars represent a public health hazard because they have thousands of hairs which contain an urticating, or irritating, protein called thaumetopoein.These hairs can be blown by the wind into contact with people and animals, resulting in painful skin irritations and rashes and, in some cases, allergic reactions in some people and animals.- PPM is not currently known to be present in the UK, but it has been extending its range across Europe towards the English Channel, and we and other plant health authorities across the UK are taking steps now to consider how the UK can best prevent, or minimise the risk of, its entry to the UK. (See "Action", below)Sightings in UKThe pest is not established in the UK, but one transient population of larvae (caterpillars) was found in a UK nursery in 1995 on Scots pine plants which had been imported from Italy in 1994. The affected trees and soil were treated, and subsequent monitoring did not detect the pest. An adult was caught in a light trap in Berkshire in 1966, but the origin of that moth was not traced.OriginIt is native to, and until recently was only found in, the Mediterranean region, North Africa and some areas of the Middle East and southern Europe.DistributionPossibly as a response to climate change, PPM has been expanding its range north through France since the 1990s, and is now breeding near Paris. Long-distance movement is thought to be associated with pupae carried in the growing medium or soil of infested plants. Climate change is thought to be responsible for the success of the moth's establishment once it arrives in regions north of its natural range.The full list of countries where it has been recorded as established is: Albania, Algeria, Austria, Bulgaria, Croatia, Cyprus, France (including Corsica), Greece (including Crete), Hungary, Italy (including Sardinia and Sicily), Libya, Macedonia, Montenegro, Morocco, Portugal, Serbia, Slovenia, Spain (including the Balearic Islands), Switzerland, Syria and Tunisia.Means of spreada. Movement of plants for planting: There is a risk of larave, or caterpillars, being moved in association with plants for planting being brought into the UK. However, the white silken nests which the caterpillars form in trees in winter are very obvious, being sometimes as big as a football. In most cases, these nests and any associated caterpillars would be clearly visible during winter and spring when plants are usually imported, greatly lowering the risk from unintentional movement of plants into the UK, as long as shippers and recipients of plants are aware of the organism.Spread by egg masses (pictured) being moved on plants for planting is considered to be a low risk, because pine trees are not usually imported and planted in the summer months, when adult moths lay their eggs, and the larvae will have emerged from the eggs before winter, when most pine plants are shipped and planted. Adult females are short lived and unlikely to remain with planting material being moved. Although thought to be a low risk, pupae (right) could be brought into the UK in the soil of pine or other host plants for planting, or with any plants which have been growing in the vicinity of infested host plants before export. Inspection is unlikely to detect pupae, which can remain in the soil for up to three years before the larvae emerge. This is the pathway by which it is believed that PPM was moved to the Paris area.There are currently no requirements for imported plants to be free of this pest. Plants for planting of many species enter the UK every year, but the volume of imports of host plants (or other plant species growing in their vicinity) with soil from areas where PPM is present is not likely to be large. The UK only imported PPM hosts (cluster pine / P. pinaster, hybrid larch / Larix x eurolepis and Scots pine/Pinussylvestris) in containers from countries in which pine processionary moth is present on six occasions between 2003 and 2012. This is a key area of uncertainty, and additional data are being sought.b. Natural Spread: Adults of both sexes can fly, and natural dispersal depends on the flight capacity of female moths, which is lower than that of males. Average female flying distance is 1.7km, with a maximum recorded of 10.5 km. This is consistent with the rate of spread recorded in the south of the Paris Basin, which has been reported as 5.6 km per year. Based on the moth's current known distribution, the risk of natural spread into the UK is still low compared to movement with plants for planting. However, its increasing northwards movement within the rest of Europe does increase the chance of natural spread to the UK.Susceptible treesPine trees (trees of the genus Pinus) are most susceptible to attack, with the following species being particularly susceptible: Austrian pine (Pinusnigra), Aleppo pine (P. halepensis), Canary Island pine (P. canariensis), lodgepole pine (P. contorta), Maritime pine (P. pinaster), Monterey or radiata pine (P. radiata), Scots pine (P. sylvestris) and stone pine (P. pinea). Other recorded hosts include the Atlas cedar (Cedrusatlantica) and European larch (Larixdecidua).Among these species, European larch, Scots pine and lodgepole pine are widely grown in the UK, although all are present. Scots pine is our only native pine.SymptomsDefoliation of needles (right) is the main symptom of PPM attack displayed by the tree itself. Complete defoliation of needles can occur where there is a high level of infestation. Otherwise the nests formed by the caterpillars in January are the most obvious signs of the moth being present. Caterpillars feed at night during the winter, when fewer people are visiting woodlands.Life-cycleThe life-cycle of PPM is different from OPM's. PPM caterpillars overwinter in tent-like nests high in pine trees, and form processions on the ground in early spring before pupating in the soil until late summer, when they emerge as adult moths. This pupal stage can, however, remain dormant, extending the life cycle over two years.The adult moths live for only about a day in the summer, during which time they mate and lay eggs in pine trees.PPM larvae, or caterpillars, hatch in autumn from the eggs laid in the summer, and begin feeding on the trees' needles in autumn.IdentificationCaterpillars: The easiest stage of the lifecycle to recognise is the larva, or caterpillar, which is hairy and coloured orange-brown with blue bands. Like its close relative the oak processionary moth (OPM), the larvae move about in nose-to-tail processions. However:OPM caterpillars often form a wedge-shaped procession, with one leader and subsequent rows containing several larvae; whilePPM caterpillars are more likely to form a single line of nose-to-tail larvae; OPM caterpillars have very long, white hairs which contrast markedly with other, shorter hairs; whilePPM caterpillars do not have extremely long hairs, instead being covered with dense clumps of hairs with less variation in length;PPM caterpillars are most likely to be seen in winter and early spring; whileOPM larvae are most likely to be seen in summer;PPM caterpillars are most likely to be seen in pine trees; whileOPM caterpillars are most likely to be seen in oak trees.Moths: Adult PPM moths have cream forewings with brown markings, and white hindwings, but to an untrained observer they are difficult to distinguish from other species of moth. They are flying about May to July, and individuals live for only about a day, during which time they must find a mate and lay their eggs in the foliage of a pine or other host tree.Nests: About January the caterpillars build distinctive, tent-like nests of white, silken, webbing up to the size of a football in the branches and foliage of pine trees, and there can be several nests in a single tree. The caterpillars spend the days in these nests, and leave them at night to forage on the trees' needles. The nests can become damaged and discoloured over time (right). Preferred trees: PPM is most likely to be found in pine trees, while OPM is most likely to be found in oak trees. Precautions - human healthShould the pest enter the UK and become established, people and animals should keep away from and not touch the caterpillars or nests. Old, abdandoned nests can still contain thousands of the irritating caterpillar hairs which can cause severe skin irritations. Parents, guardians, teachers and others responsible for children's welfare should teach them the dangers, and dog owners and walkers should keep dogs away from the caterpillars and nests.People with symptoms who thought they might have been in contact with the hairs should seek medical advice, explaining that they believed they had been in contact with PPM hairs. Similarly, pet and livestock owners whose animals displayed symptoms should consult a veterinary surgeon and explain that the animal might have been in contact with PPM hairs.Outbreak managementShould the pest be found to have entered the UK, the first response would be to try to eradicate the outbreak to prevent establishment. Using emergency powers available to us, we would issue statutory Plant Health Notices to affected tree owners requiring them to have the infestations removed. Possible treatment options include pesticide applications during the larval stage of the lifecycle, and manual removal of nests and caterpillars by trained operators.SymptomsMore information can be found at: http://www.forestry.gov.uk/forestry/INFD-924HD6
Slide Comments:All noted on slide.Image Details:Top Left: LarvaeTop Right: The AL BeetleBottom: Breeding exit holesAdditional Information:From Forest Research Expert:-There was an outbreak in Kent last year which has been eradicated. From Asia but there are outbreaks in North AmericaAssociated with wood packagingEarly sightings are important.From the Forestry Commission WebsiteAsian longhorn beetle is a native of China and is present in the Korean peninsula, and poses a serious threat to a wide range of broadleaved trees. It has caused extensive damage to trees in the USA and Italy since being accidentally introduced there in recent years.They are almost identical in appearance to citrus longhorn beetle (Anoplophorachinensis), another non-indigenous longhorn beetle that threatens trees in Britain.More information at: http://www.forestry.gov.uk/forestry/HCOU-4U4J45#action
Slide Comments:All noted on slide.Image Details:Top : LarvaeBottom: The CL BeetleAdditional Information:From Forest Research Expert:- Moves on ornamental plantsLots of interception but no outbreaksDiffers from Asian Longhorn beetle in its thorax shield and it makes holes lower on the trunks of trees.It is important that if found, to capture in a suitable container and ring Forest Research. The pest is an expensive problem to get rid of, in Lombardy they are spending 10 million Euros to eradicate it.From the Forestry Commission WebsiteThe Citrus longhorn beetle (Anoplophorachinensis) is a serious invasive pest that is found in South East Asia. EU listed quarantine pest – entry is completely banned. A minimum two-year quarantine period is required to ensure freedom. Citrus longhorn beetles can infest a very wide range of broadleaved trees and would be a major threat to horticulture and the wider environment if they became established.Very difficult to detect as eggs or when larvae are hidden in stems.Most of the Citrus longhorn beetles that have been found to date in the UK have been associated with Japanese maple trees imported from China.Serious outbreak in Italy (Lombardy)More information can be found at: http://www.fera.defra.gov.uk/plants/plantHealth/pestsDiseases/clb/index.cfm
Slide Comments:The third section: Conducting the survey…
Slide Comments:Consider the weather.Don’t carry out the survey in high windsParticipants need to be appropriately dressed and shod.Don’t work aloneCheck the area for signs of danger:Look up: Check trees for broken branches that might fall and for low hanging twigs and branchesLook down: check the ground for obstacles, prickly or stinging plants. Don’t survey at the edge of a lake or riverLook out for other site users, if forestry operations or hedge trimming is going on choose another site.We need to consider our own biosecurity. If you are surveying at more than one site, you need to clean your shoes between sites, otherwise clean your shoes when you get home.
Slide Comments:Field NotebookTakes you through the survey and is where you write down your findings.There is an additional table at the back for recording results for more trees if you decide to survey more than one.NB – additional recording sheets available to download from the OPAL website if you want to record data for more than three trees.Field ID Guide Gives s additional information on pests and diseases Has instructions for measuring crown transparency and tree heightMost unwanted Gives details on serious pests and diseases, this can be used as a stand-alone activity, particularly for people who are regularly in the field.A2 Fold-out Tree GuideTape measureA 3-5m tape is sufficient to measure most trees.ChalkA camera pictures will help confirm your records of pests and diseasesA map or GPS Smart Phoneto give a grid reference for your site,to use the Tree Health Survey Appto record a sighting of one of the most wanted on the ‘TreeA!ert’ App
Slide Comments:The fold out id guide has a key on one side together with an explanation of the terms it uses and on the other side pictures that you can use to confirm or check your id, there are also species profiles of our target species.The guide isn’t complete – particularly if you are working in parks or gardens there may be ornamental species that you won’t be able to identify from it. Tips for identifying trees:Tips for our target species:Check the ground, there may be acorns/cups or conkers/casings or ash keysleaves from last year.Oak and ash are common woodland and hedgerow trees, horse chestnut tends to be found as a planted parkland or wayside tree.Oak: has simple lobed leaves, pinate (with the veins coming from different points from a central vein)Ash – has compound leaves with pairs of untoothed leaflets. The leaves are paired on the twigs, unlike rowan which it might be mistaken for. The twigs are grey with black buds that look like little hooves.Horse chestnut – has compound palmate leaves with leaflets all coming from one point. The buds are big, shiny brown and sticky.
Slide Comments:Right at the start of the survey there are some questions asking for details of the person undertaking the survey. We are collecting some background information to help us assess the level of confidence we might have in the data. All data is important and will be used, but this information enables us to give stronger weight to results collected by those likely to be more accurate… This information also helps us understand the reach of our surveys and who is taking part.Activity 1 can be carried out on any tree, but preferably on oak, ash or horse chestnut, as this will allow you to do the full survey on one tree, and will give us a really good picture of your tree’s health.A: Site information – We want people to be as specific as possible about location. GPS is ideal. Exact trees can be pin-pointed when entering the date on our website using google maps. We also want to know what the survey area is like, and what the ground beneath the tree is covered with, as this will help us understand possible disturbance and root damage to the tree (e.g. concrete may restrict the roots, bare soil could indicate ploughing which can damage roots). Fallen leaves are important, as fungal diseases may spread from infected leaves. This data will help us see if there are patterns between site characteristics and the spread of particular pests and diseases.B: Identify your tree, using the fold out tree guide. We are encouraging people to take a photo of their tree and submit this with their results. There will be a gallery of people’s trees on the OPAL website.C: Tree Characteristics: record its girth and height (there will also be a facility on the OPAL website to estimate your tree’s age). This gives us some background info on the age and condition of the tree you are surveying and its dominance in the landscape (i.e. in relation to other trees). These are also nice, fun activities to ease people into the survey and to familiarise themselves with the tree.D: Tree Crown – section C gets you to make observations on the condition of the tree’s crown…this includes crown shape, crown density and whether there are any dead branches in the crown. For Question 13 use the crown density card in your pack, stand under the tree crown and look up to estimate the crown density. This gives us information as to whether there is any defoliation or die-back in the crown. (Defoliation is where the leaves have died, dieback is where the twigs have died so the whole branch looks bare). Question 14 asks you to look at the crown to see if there is any dead wood in the crown (i.e. branches without leaves OR twigs)E: Leaves – section E gets you to make observations about the leaves, (leaf yellowing, browning and leaf damage) – leaf browning can be caused by many different factors including insect damage and sea salt. Leaf yellowing is often a sign of a longer term issue and can indicate root damage. You are also asked to look for signs of any insect damage on the leaves of the tree.F: Wildlife – It is important that people are aware of the biodiversity value of trees (and that old trees with deadwood, cracks, splits and hollows are very valuable for wildlife). As you talked about earlier, dying is a natural part of a trees life cycle. Epiphytes and other things growing on a tree can enhance wildlife value. Section F gets you to look for signs of other wildlife or possible habitats for wildlife, on your tree.
Slide Comments:Stress the importance of photos so that any sightings can be confirmed.
Slide Comments:Stress here that it is vital they take a photo if they think they have spotted a ‘Most Unwanted’ pest or disease.People are unlikely to find most of these in their surveying – some are not yet present in the UK, but are serious so we want to make sure that if they do arrive we are able to spot them straight away. If you do think you spot one of the ‘Most Unwanted’ then it is vital you notify government officials so that the right action can be taken. You should:If you think you see one of the Most Unwanted, make sure you take a photo and submit this via the OPAL website or the Tree Alert App/ webpage…(try to get a good shot – if needed take several until you have a good one).Alert the Forestry Commission directly (through Tree A!ert App or by phoning the helpline numbers on the ‘Most Unwanted’ guideSubmit your siting through the OPAL websiteRemember there is additional info to help you identify your siting on the OPAL website and also the Forestry Commission website. If in doubt, send in your photo so an expert can verify it!NB if you think you see one of the longhorn beetles but don’t know whether it is the Asian Longhorn or Citrus Longhorn, please submit it as either as action will be required for both.It is a legal requirement that sitings of the ‘Most Unwanted’ are reported, and photos are imperative to confirm the siting. When submitting a siting, the recorder will be asked to provide contact details (part of the legal requirement for reporting one of these pests or diseases), because it is important that the relevant authority is able to follow it up.
Slide Comments:Participants will get instant feedback on the results map.This data will be sent through to OPAL and Forest Research who will analyse the data.Results can be submitted via the OPAL websiteA freepost address is also available for those without internet accessResults for Activity 1, 2 and 3 can be submitted separatelyPhotos can be uploaded with the results (maximum of 3)Try to record your location as accurately as possible, in case we need to trace the tree you surveyed…
Slide Comments: -Good crown density, leaf colour and no signs of other damage are a general indication that your tree is in good overall condition.- High levels of defoliation and/or discoloured leaves often mean that a tree is less able to produce ‘food’ and will grow at a slower rate than a healthy tree.- Oak decline and ash decline may indicate the tree is suffering a range of problems, which are weakening the tree’s overall vigour.- Weather events, climate change and human activity can influence the distribution of pests and diseases.. Your records will be added to the OPAL website and the UK central tree health database to display and help monitor the geographic distribution of reported tree pests and diseases.- Reports of our ‘Most Unwanted’ pests will allow monitoring of quarantine pests and diseases in the UK.
Slide Comment:Make sure trainees are aware of the health and safety for this session.Head outside to conduct the Tree Health Survey…
OPAL Tree Health Survey training presentation
OPALTree HealthSurvey TrainingMay 2013
• Introduction to UK forestsand Tree Health• Pests and Diseases• Conducting the survey• Practical Training
Trees are good forour wealth, healthand happiness bothnow and in thefuture.Economy Wellbeing BiodiversityClimate Change National Heritage
• Trees have a life cycle• Usually trees are healthy• An increasing number of new pests and diseases areattacking trees in the UK• Increasing world trade and climate change are two contributorycauses for the increase
The Government works to protect the country frompests and diseases by:o Plant health legislationo Inspecting importso Inspecting woods and plant nurserieso Campaigns to eradicate outbreakso Conducting researcho Raising people’s awarenessWhat we can all do to help:o Public engagement assists with surveillanceo This is where OPAL fits in… We need your help!
Previous OPAL Surveys: The Tree Health Survey:Soil andEarthwormAir BiodiversityWater Climate Bugs Count
What are plant pests and diseases?Pests: usually invertebrates(insects, mites, nematodes)Diseases: caused by pathogens(fungi, bacteria, viruses)Survey will focus on 18 pests and diseases
2003 20052011Horse Chestnut Leaf MinerChalara ash diebackMonitoring pests and diseases affecting Britain’s trees aids ourunderstanding of their impact, their changing distribution and helps tomanage their spread.For Example:
Knopper Gall wasps (Andricusquercuscalicis) arrived in southernEngland in the 1950s and have nowinvaded most of the UK.• Ridged and knobblyprotrusions on acorns(from July onwards)caused by a tiny gallwasp• Does not kill tree but affectedacorns cannot germinate
The roller moth, Tortrix viridana, is a native species of micromoth.• Loss of leaves in May and June• Edges of leaves curled up into a tube• Heavily infested trees can be completely defoliated• There are other native defoliators on oak
• Attacks young leaves andsoft shoots, covering themwith felty-white myceliumand dry powdery spores• Leaves may shrivel and blacken• Mild overcast conditions are optimal fordevelopment of the disease, usuallyappears in summerErysiphe alphitoides is a common foliarfungal pathogen of oak throughoutEurope. First found in England in 1908, itcontributed to an oak dieback episodethe 1920s.
Oak decline is a complex disorder:Several damaging abiotic (e.g. drought) or biotic (e.g.insects and fungi) agents interact. It can be simultaneous&/or sequential and outcome can be a serious decline intree health, may be terminal, but trees can also recover.Not a new disorder but recently we have come torecognise:• Chronic Oak Decline (COD): slow effect about 10-50years, focus on roots• Acute Oak Decline (AOD): fast effect approximately 3-5 years, focus on above ground parts
Serious episodes of oak decline havebeen documented for almost 50 yearsin the UK.• Early signs areyellowing or fewerleaves• Later, dead branches can be seen• Severe cases, dark weepingpatches on trunk which dry toblack crust• D shaped holes in trunk bark• Canopy dieback and /or thinning• Bacterial lesions Agrilus beetles
Photograph courtesy of Nigel Straw, Forest Research• Sparse foliage• Wilted and blackened leafshoots (May onwards)• You mat find entrance / exitholes in buds and at baseof wilted shoots• Silken webs and frass (fragments ofbark) may also be visible• Symptoms most obvious on youngertreesThe ash bud moth Prays fraxinella, is anative species of micromoth.
• Look for a woodyencrustation on the stalkof the ash keys• Galls are green at first becomingbrown later• Older galls can remain attached forover a year, so visible for year round• The galls make ash keys heavier sowind dispersal is hinderedAlso known as cauliflower gall, it iscaused by the eriophyid mite Aceriafraxinivora.
Photograph courtesy of Nigel Straw, Forest Research• New cankers look like adepression on the trunk orbranches• Causes death of twigs• Centred on small branch stubs or theirremains• Older cankers look like a target: concentricrings of dead woodNectria canker is caused by the fungusNeonectria galligena. It is a native diseasewhich may be linked to existing wounds,causing dieback of twigs and sometimesbranches to break.
Ash decline is caused by acombination of factors that affect theroots and causes a gradual decline inthe tree.• Death of a number of twigsand branches• Poor growth in the crown• Common in hedgerow treesbeside ploughed fields,especially on drier sites• Dieback is progressive over a number of years.• Recovery is possible and trees take on appearance of a healthy crown withsome dead branches
• Red-brown blotches onleaves, outlined in yellow• Hold the leaf up to the light – blotchesare not translucent• Blotch spreads across leaf veins• Disfigures but does not kill tree• May appear in combination with HorseChestnut leaf minerPhotos courtesy of Nigel Straw, Forest ResearchCaused by the fungus Guignardia aesculi,this disease was first reported in Britain in1935.
Horse chestnut leaf miner• Brown blotches on upper or lowersurface of leaves• Hold the leaf up to the light – blotchesare translucentThe micro moth, Cameraria ohridella arrived in theUK in 2002 from Europe. Ten years after the pestwas first seen in Wimbledon those trees remain ingood health.• Mines constrained by leaf veins• May appear in combination with HorseChestnut leaf blotch• Severely damaged leaves shrivel andturn brown in late summer
• Rusty coloured liquid oozes fromtrunk bark• Liquid dries to black crust at pointof exit• Severely affected trees have thinning crowns withdead branches• Severe attacks can kill trees• Bark killing may be so extreme that damaged barkpeels of tree exposing wood beneathPhotos courtesy of Nigel Straw, Forest ResearchCaused by the bacterium Pseudomonas syringaepathovar aesculi, this disease suddenly appeared inthe early 2000s.
• Circular white spotstopped with brownor orange on trunkor branches• Found on many tree speciesincluding Horse Chestnut,Sycamore and Lime• Visible in May and June• Disfigures but does not kill treeCaused by the insect Pulvinaria regalis,first found in Britain in 1964
Chalara fraxinea emerged as anentirely new disease in Europe in the1990s and first found in Britain in2012.• Stem lesions typicallycentred on side branchinfection• Death of twigs andbranches• Girdling of shoots and stemsresulting in dieback, young treesparticularly vulnerable• Common ash (Fraxinus excelsior)very susceptibleH. pseudoalbidusfruit bodies onfallen ash
• Initial thinning and yellowingof foliage• Tunnels made by larvae inthe bark have sharp bendsand meanders• Bark has narrow fissures (cracks) about5-10 cm long, caused by scar tissueproduced by tree after larval feeding• D shaped holes (c.3mm diameter)produced in trunk by emerging adultsPhotos courtesy of Nigel Straw, Forest ResearchAgrilus planipennis is NOT present inUK, its arrival would be a cause for greatconcern.
Photos courtesy of Nigel Straw, Forest ResearchThaumetopoea processionea is presentin London and areas of Berkshire.• Caterpillars cause defoliation• Caterpillars show distinctivehabit of moving about in latespring and early summer innose-to-tail processions• Build distinctive white, silken webbingnests in oak trees and leave white trails upstemCauses human health problemsAVOID any contact!
• Caterpillars causedefoliation of needles• Most distinctive life stage is thecaterpillar, which is coloured orange-brown with blue bands covered indense clumps of hairs. Wedge shapedprocession moving nose-to-tail• Caterpillars most likely to be seenwinter and early spring. Overwinter intent-like like nests high in Pine treesThaumetopoea pitycampa NOTpresent in UK.Causes human health problemsAVOID any contact!
March 2013• Infest a wide variety of treespecies, especially Poplar,Sycamore and Willow.• Adults are black shiny, 20-35 mm long and 7-12 mmwide with about 20irregular white spots• Distinctive long antennae. Antennaesegments are black with distinctive blue-grey/creamy-white base.• Circular breeding exit holes are up to 10mm in diameter, usually higher on the trunkthan the Citrus Longhorn BeetleRecent outbreak of Anoplophora glabripennis in Kent was eradicated, soNOT present in UK. Would be a major threat if they became established.
• Very similar in appearance to theAsian Longhorn beetle• Could infest a wide variety of treespecies, especially maples• Adult beetles are large and black with variablewhite markings• They have very long antennae which are blackwith white/light blue bands• Circular breeding exit holes 5-10 mm in diameterhave been found on maple saplings, usually nearthe base of the trunkAnoplophora chinensis is NOT present in UK. Would be a major threat tohorticulture and the wider environment if they became established.
• Check thewebsite• Read theinstructions• Landownerspermission• Health and safetyhttp://www.opalexplorenature.org
All the equipment that you need is in thepack, which contains:Field Notebook Field GuideFold Out Tree GuideMost UnwantedGuideTape MeasureOptional Equipment:CameraOS Maps or GPSSmart PhonePencil
Activity 1 can be carried out on any tree, but preferably on Oak, Ash orHorse Chestnut.
This activity can be done on Oak, Ash or HorseChestnut only.• Ideally survey the same tree as used in Activity 1• Use the field guide to identify whether your treehas any of the four pests/diseases of your chosentree speciesPlease take a photo if you think youidentify any of the pests/diseases on yourtree
This part of the survey can be done onany tree, and at any time• Results can be submitted independently ofthe rest of the survey• Use Most Unwanted guide to help withidentification• Health and safety• Bio-security guidanceTake a photo of the Most Unwantedand submit via the OPAL website or the TreeAlert App/ webpage…http://www.forestry.gov.uk
• Submit via the OPAL website orfreepost address• Activity 1, 2 and 3 results can besubmitted independently• Photos• Record your location accuratelyIt’s really important that you send us your results once you have donethe survey.
Good crown density, leaf colour and no signs ofother damage = tree is in good overall conditionHigh levels of defoliation and/or discolouredleaves= tree will grow at a slow rateOak decline and ash decline = tree is sufferinga range of problemsWeather events, climate change and humanactivity = influence the geographic distributionof common tree pests and diseasesReports of our ‘Most Unwanted’ pests = trackthe arrival and spread of quarantine species
Thank you… Questions?Photos courtesy of Forest Research and Fera
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