XxxxxxxxxxxxxxxxxxxxxxxxxxxxX XX e.NEWSLETTER XX No 22. September 12 , 2011 X X Fighting for public green space in West Dulwich i xiixxiix _ _____________________________________________________________________________________________________________________________________________________________________ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx XX A view towards the Lakeside Wildlife Walk on August 3, 2011 shows how a mature horse chestnut (left) had XX XX already turned decidedly autumnal in appearance. This is actually the work of leaf-mining caterpillars. An early sense of autumn. X x xxxx x x x x x xx x x x x x x x x x x x xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Friends Chair, Dr. Martin Heath: “ The height of summer is passed, and the days have XX been drawing in noticeably. Talking to park users, I hear comments about the air XX feeling autumnal. For me, a definitive moment in the downturn of the year was at XX around 6 pm on August 18, when, with the sky darkened by a rainy overcast, and the XX lights already having come on under an av enue of trees in front of Euston station, there XX XX was a chill in the air that told me that a sweater was not enough. An early crop of blackberries XX XX and X other fruits have helped an impression of autumn. The Royal Horticultural Society has XX XX attributed this and premature autumn colours on many trees, to a hot and dry spring. With this XX XX sense of the year drawing on, I found myself looking back over its events, and realised just how XX XX much – with your help – the Friends, together with their allied organisation New Leaf, have XX X X actually achieved in 2011. Spring and summer were extremely productive, and now we are XX XX concentrating on tidying up, working on paths, containing brambles within specified areas, XX XX planting up islands and marginal areas, and taking stock of wildlife. Assisted by Penelope Stanford, XX XX I have continued to tour the hedgerows of Kent, studying their structure and micro-environments, XX XX and picking up ideas about how some of their features might be re-created in Belair Park. ” XxxxxxxxX xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Disease hits Horse Chestnuts. xxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xx The early browning of the horse XX chestnuts, which has been underway for XX weeks, has reinforced the sense of a XX premature autumn. It is sad that, these XX magnificent trees have been the victims XX of a pest for which horticulturalists have XX no easy remedy. Photo: Aug. 28, 2011. x x x x xx
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XXe.NEWSLETTER XXNo 22. September 12, 2011 XXFighting for public green space in West Dulwichixiixxiix
XXA view towards the Lakeside Wildlife Walk on August 3, 2011 shows how a mature horse chestnut (left) hadXX XXalready turned decidedly autumnal in appearance. This is actually the work of leaf-mining caterpillars.
An early sense of autumn. X x xxxx x x x x x xx x x x x x x x x x x x xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Friends Chair, Dr. Martin Heath: “The height of summer is passed, and the days haveXX been drawing in noticeably. Talking to park users, I hear comments about the airXX feeling autumnal. For me, a definitive moment in the downturn of the year was atXX around 6 pm on August 18, when, with the sky darkened by a rainy overcast, and theXX lights already having come on under an avenue of trees in front of Euston station, thereXX
XXwas a chill in the air that told me that a sweater was not enough. An early crop of blackberriesXX XXandXother fruits have helped an impression of autumn. The Royal Horticultural Society hasXX XXattributed this and premature autumn colours on many trees, to a hot and dry spring. With thisXX XXsense of the year drawing on, I found myself looking back over its events, and realised just howXX XXmuch – with your help – the Friends, together with their allied organisation New Leaf, haveXX XXactually achieved in 2011. Spring and summer were extremely productive, and now we areXX XXconcentrating on tidying up, working on paths, containing brambles within specified areas,XX XXplanting up islands and marginal areas, and taking stock of wildlife. Assisted by Penelope Stanford,XX XXI have continued to tour the hedgerows of Kent, studying their structure and micro-environments,XX XXand picking up ideas about how some of their features might be re-created in Belair Park.”XxxxxxxxX
Disease hits Horse Chestnuts.xxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xx
The early browning of the horseXX chestnuts, which has been underway forXX weeks, has reinforced the sense of aXX premature autumn. It is sad that, theseXX magnificent trees have been the victimsXX of a pest for which horticulturalists haveXX no easy remedy. Photo: Aug. 28, 2011.x x x x
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xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx XXThe horse chestnut (Aesculus hippocastanum) was introduced into Britain around 1600 and isXX XXconsidered to be naturalised. It is one of the trees that most school children recognise, because itXX XXprovides conkers. Its native environment is a restricted area in the mountains and foothills of theXX XXBalkans, in parts of Greece,XMacedonia, Albania, Serbia and Bulgaria (Vĕtvička,1985). EntomologistsXX XXfrom the Royal Horticultural Society discovered the leaf-miner in Wimbledon in 2002, where, theyXX XXdecided, it had probably been established for at least a year. The problem of browning leaves inXX XXthis iconic tree has been discussed in TheXGarden, the RHS' magazine, and, of course, in theXX Xxpopular press by gardening writers such as Diarmuid Gavin, so it is becoming well known.
Browning is caused by the caterpillar of theXX chestnut leaf miner moth (CamerariaXX ohridella), a native of Greece, which reachedXX Britain about a decade ago. The species wasXX noted in 1984 in the area of the Ohrid Lake,XX Macedonia, and it was described in 1986XX (although it has been found in herbariumXX specimens collected in central Greece in 1879).XX The 5 mm long adult moth lays its eggsXon theXX upper surfaces of leaves and they hatch 2 to 3XX weeks later. In hot and dry climates the mothXX can pass through 5 generations per year,Xbut 3XX is likely in more temperate climates.X
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XXXXXxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxXXXAbove: Image from soebe, Hamburg, Germany, 2006.xx x x x x x x x x x x x x x x x GNU Free Documentation License.
XXLeft: Larva of the leaf-miner moth. Image from Beentree, Bialowieza, Poland, XX2006). GNU Free Documentation License.
XXAs a larva develops, it will expand mining activity, before, some 4 weeks XXafter hatching, it enters a pupal phase, which lasts 2 weeks. The pupae XXof the year's final generation overwinter in fallen leaves. According to a XXfact sheet emailed out by Southwark Ecology officer Jon Best, the best XXsolution is to collect all the fallen leaves and put them in the Southwark XXgreen waste bags. They will be taken to a commercial composting site, XXwhere the high level of heat attained will kill the pupae. Garden XXcomposting rarely reaches temperatures high enough to kill the pupae. XXBurning horse chestnut leaves is a less environmentally friendly method XXoficontrol.xx
Above: Conkers on the LakesideXWildlifeXWalkXX (Sept. 6, 2011).
By damaging the leaves (which enable trees toXX produce their own foodstuffs andXtissuesXX through photosynthesis) the disease reduces theXX efficiency of growth and reproduction, but it isXX not considered to result in the death of treesXX nor in them becoming dangerous and needing toXX be felled. Also, although A.hippocastanumXX (noted for its attractive displays of pyramidalXX spikes of white flowers, which come out inXX May), has been hit hard, neither the red horseXX chestnut (Aesculus x carnea) nor the IndianXX horse chestnut (Aesculus indica) are affected.
Upper left: Horse chestnut at New Ash Green, KentXX (Sept. 4, 2011). This tree exhibits some signs ofXX attack by the leaf miner, but its leaves are inXX better condition than those of horse chestnuts inXX Belair Park. Centre left: Fallen horse chestnutXX leaves in Belair Park (Sept. 6, 2011). Lower left:XX Yellowing leaves, Belair Park (Sept. 6, 2011).XX Images: M. J. Heath, unless otherwise stated.
Gill Manuel, Chair of the Dulwich Society treesXX subcommittee noted that horse chestnutsXX around Dulwich appeared in rather betterXX condition this year than they did last year. SheXX also reminded us that the leaf miner is not theXX only problematic disease attacking this tree.
Further information: x xxxxxxxxxxxxxxxxxx x x x x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Deschka, G. & Dimić, N. (1986). Acta Entomol. Jugosl.XX 22: 11-23.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Lees, D. C. et al. (2011).'Frontiers in Ecology and theXX Environment.Xdoi:10.1890/100098. xxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Percival, G. C. et al. (2011). Urban Forestry & UrbanXX Greening. 10: 11-17.xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
U.K. Forestry Commission. Horse chestnut leaf miner,XX Cameraria ohridella Desch. & Dem. (Lepidoptera:XX Gracillariidae) Exotic pest alert. See also website:XX http://www.forestresearch.gov.uk/fr/INFD-6Q3DPF. xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Vĕtvička, V. (1985) The Illustrated Book of Trees andXX Shrubs. English edition. E.XXLawrence (Ed.).XTranslationXX by I. Kuthan and O. Kuthanová. London,U.K.: OctopusXX Books. X
The Committee, Friends of Belair Park.xfriendsbelairpark(at)hotmail.co.uk (tel: 020 8670 8924). x x x
