5o Insect Depredations in North America, [april, 



Larch Rust. — A branch of a Scotch fir was recently sent to 

 the Board from a nursery in Northumberland showing in a 

 well-defined manner the presence of larch rust (Melampsora 

 laricis Hart). The aecidial stage of this fungus forms 

 yellow pustules on the leaves of the larch, while other stages 

 are passed in the living leaves of poplars and birches. The 

 spores produced on these leaves are conveyed by wind or other 

 means to the leaves of the fir, for which reason when disease 

 is suspected seed-beds of conifers should not be made in the 

 neighbourhood of these trees. The disease, which almost 

 exclusively attacks very young trees, was not reported as 

 being serious in the case above mentioned. 



Violet Root Rot. — Bean plants sent from Roweden, Kent, 

 were found to be affected with Rhizoctonia violacea (Leaflet 

 171). They were grown in pots in fresh soil. The outdoor 

 crop last year was lost, and an earlier crop this year was 

 affected. 



A Bulletin recently issued by the United States Department 

 of Agriculture (Bureau of Entomology, No. 58, Part V.) refers 

 to the very extensive damage done to 

 Insect Depredations forest trees in North American forests 

 in North American by insects, and Dr. A. D. Hopkins, the 

 Forests. officer in charge of Forest Insect Inves- 



tigations, estimates that the loss due to 

 insect pests represents 1 per cent, annually of the total stand 

 of merchantable timber in the United States. This figure, 

 based on the estimated area and stand of the present forests 

 of the United States, and the average stumpage value, is 

 equal to a value of about 13 million pounds sterling 

 annually. 



Among the pests which have done widespread damage is 

 the large larch sawfly (Nematus erichsoni), which is of 

 special interest owing to its recent extension in Great Britain. 

 As was stated in the recent article in this Journal, March, 

 19 10, p. 982, this insect is believed to have destroyed, since 

 1880, from 50 to 100 per cent, of the mature larch over vast 

 areas in the north-eastern United States and south-eastern 

 Canada. 



Many other insects have from time to time been equally 



