DAXGEROUS INTERNATIONAL FOREST TREE DISEASES 19 



Investigations of recent years show damage to Italian poplar 1-214 

 and other susceptible poplars by late frosts. Populus simoni suffers 

 in the CSSR from brown spotting disease and Dothichiza populea 

 (Chondro plea populea (Jacc.) Kleb.) 



Septoria musiva Peck has not yet been found. 



Graphium uhni Schw. damages the elm in forests, parks, and along 

 streets. Foreign elms have not yet been introduced to our country. 



Czechoslovak forest management relies mainly upon native tree 

 species. Douglas-fir is the only introduced tree species of considerable 

 economic importance. Exotic tree species and their diseases are given 

 more attention in gardening and park management. 



Great Britain 



T. R. Peace 



Formerly Chief Research Officer (Deceased), Forestry Commission. 

 Forest Research Station, Wrecclesham, Farnham, Surrey, England 



Pressure of existing commitments and staff changes have prevented 

 any substantial developments in forest pathological work in Britain 

 over the last few years. This has inevitably affected our international 

 activities. 



Probably the most significant piece of work, internationally, was 

 the organization, under the auspices of IUFRO of a meeting of persons 

 actively interested in the fungus Fomes annosus. This was held in 

 Scotland in May 1960, and involved a number of forest excursions as 

 well as meetings; 23 delegates from 9 countries attended including 5 

 from North America. A report, containing the papers presented by 

 delegates, an account of the field tours, and a summary of the discus- 

 sions, has been prepared and is now with Dr. Biraghi, Chairman of 

 Section 24. who is dealing with the question of publication. 



A list of fungi attacking the genera Pinus, Populus, and Qu-ercus 

 in Britain has been prepared as part of the general scheme. It is my 

 view that before these lists are finalized more thought must be given 

 to the evaluation of the status of the diseases mentioned. The terms 

 used at present are too vague. In addition, value would be added to 

 the list if degree of susceptibility could be mentioned where sound in- 

 formation is available. For instance, Melampsora pinitorqua has been 

 recorded on Pinus nigra calahmca in Britain, but this record rests on 

 one or two occurrences with negligible damage. Only on Pinus syl- 

 vestris has it so far proved damaging. 



A good deal of the work currently in progress has a definite inter- 

 national interest. Tests of large numbers of poplar clones for their 

 resistance to bacterial canker and the field testing of elms, including 

 some of those produced in Holland, for resistance against Ceratocystis 

 uhni are cases in point. The test area of two-needled pines and aspen 

 poplars to get information on susceptibility to Melampsora pinitorqua 

 has yielded some information on American (Pinus resinosa, Populus 

 tremuloides, P. grandidentata) as well as on European species: but it 

 has proved extremely difficult to maintain in an actively infective 

 condition and is being abandoned. 



In August and September 1960, J. S. Murray made an extensive 

 tour in Denmark, Germany, and Belgium, visiting Research Stations 

 and inspecting diseases in the forest. During the period in Germany 



