REPORTS BY THE HONORARY SCIENTISTS. 343 



REPORTS BY THE HONORARY 

 SCIENTISTS. 



1. Report by the Honorary Cryptogamist. 



During the past year I have received, among other patho- 

 logical specimens for identification, only four which are of general 

 interest to foresters. Three of those cases were different diseases 

 of the pine, while the fourth one related to the larch. 



Pine : — Case I. Leaf -shedding fungus (Lophodermiuni Pinastri). 

 This disease affects principally seedlings or young trees, and, 

 when it has once made its appearance in the nursery, unless very 

 stringent measures are early adopted, its eradication becomes a 

 very difficult matter. The spores are very readily carried by wind, 

 and, if the moisture conditions are favourable, the disease becomes 

 epidemic. The first symptoms of the disease may appear in autumn, 

 in seedlings of the current year, by the primary leaves assuming 

 a speckled brownish-red colour. This is often accompanied by 

 the formation of numerous minute black spots, in which conidia 

 are produced. Those conidia are, however, incapable of infecting 

 other trees. It is in the ascospores, produced in larger black 

 swellings (asci), which usually appear in the second or third 

 year, that the danger of infection lies. It is only in very wet 

 summers, or after long-continued rain, that the spore-cases are 

 ruptured and the spores liberated. A mild winter, therefore, 

 following a moist summer, is extremely favourable to the spread 

 of this disease; hence foi'esters would do well to keep a sharp 

 look-out on their young pines during the coming winter if they 

 have any reason at all to suspect the presence of this parasite. 

 Reviedy mid Preveiition. — Some small amount of good may be 

 done by uprooting and burning infected plants directly they show 

 the first symptoms of attack, but, if the disease is at all prevalent, 

 this becomes impracticable. As regards prevention, a considerable 

 amount of good may be done by keeping the young healthy plants 

 to the windward of previously infected ones, and also, if possible, 

 to intercalate the beds between those of another species. In fact, 

 anything which tends to prevent the spores being carried by the 

 wind to young plants will help to check the spread of the disease. 

 Further, crowding of the young plants, or overshading by others, 



