March 1896.] INJURIOUS INSECTS AND FUNGI. 



ou warm is also destructive to mossy and lichenous growths^ 

 and hot lime tlirown all over the trees in damp weather is very 

 efficacious if the lime is caustic and put on properly. 



"Fiheblast" of Hops. 



In the season of 1895 hops were largely affected by a 

 disorder known colloquially as " tireblast," occasioned pre- 

 sumably by the long continued drought. The leaves of the 

 hop-plant atfected with " fireblast become bronzed in colour, 

 and in some cases are covered with blotches of a dark 

 brown colour, evidently resulting from the tissues being dead. 

 After a time the leaves dry up and fall off. It was noticed last 

 season that " Fuggies " were more subject; to this disorder than 

 other varieties, especially upon gravelly and " pinnocky " soils,, 

 and on those " near to the rock." The results were something 

 like those occurring from red spider attacks, but no red spiders 

 were discovered upon the leaves examined. One form of this 

 " fireblast " was certainly due to a fungus, at present undeter- 

 mined. There were other forms of fireblast in which the leaves 

 were marbled, or variegated, in colour, due, as it appeared, to lack 

 of moisture. Professor Percival gave much attention to fire- 

 blast last autumn, and holds that a fungus is responsible for one 

 at least of the forms. He considers this fungus to be Hetero- 

 sporium minutidum (Cooke and Massee). But he remarks, " By 

 far the greater number of cases of fireblast are brought about by 

 other causes than red spider, or attacks of fungi. In more than 

 70 per cent, of the cases of the most virulent type — that is, where 

 the disease is most pronounced and damaging to the plants — no 

 insect or parasitic fungus can be detected. . . . There is no 

 doubt that this form of disease is the one most commonly met 

 with, and may be called fireblast proper. Its cause is also 

 without doubt connected with the soil. Practically every 

 example of this trouble examined this year was met with where 

 the soil or subsoil was gravelly in nature or very varied in 

 character. I have never seen it on deep uniform soils." 



This experience of Professor Percival tallies with the results 

 of observations made last season. 



After the heavy showers in August the disorder was arrested. 



It was noticed that the application of sulphur had no effect 

 upon fireblast, and that cultivation and manuring did not check 

 its progress. 



