160 Scientific Proceedings, Royal Dublin Society. 



Within the last month I have received specimens of cankered 

 rods from Co. Kilkenny, through the Department of Agriculture 

 and Technical Instruction. Microscopic examination shows that 

 the cause of the canker is here also a species of Physalospora. 



Summary. 



1. The osier-canker, which renders the diseased rods worthless 

 for basket-work, is caused by the ascospore-forming fungus 

 Physalospora gregaria, Sacc, which has associated with it two 

 other stages, here distinguished as Tetradia salicicola and Macro- 

 dendrophoma salicicola. The former may be the microstylospore 

 and the latter the macrostylospore stage of Physalospora gregaria, 

 Sacc. Were they not septate, the conidia in the Tetradia stage 

 might be the spermatia of the spermogonium of Physalospora. 



2. Judging from analogy, all three fruiting stages are capable 

 of infecting healthy willows. 



3. The sets when planted were diseased. 



4. The new habitat — poor, undrained, raw bog — and prevalence 

 of weeds have favoured the fungus. 



5. The fungus has, under the circumstances, killed off some of 

 the sets ; in some cases has caused the rods formed to be few in 

 number and small in size ; and in other cases, by forming the 

 cankers, has spoilt them for basket-manufacture purposes. 



6. The cankers are the external sign of the general permeation 

 of the set and its shoots by the fungus mycelium or hyphse. 



7. Every care should be taken not to plant diseased sets from an 

 infected holt. 



8. The land chosen for osier growth should be well-drained, to 

 avoid stagnant water or sour soil, and should be well-manured. 

 Bog-land is especially poor in lime, potash, and phosphatic mineral 

 food-materials. 



9. As soon as disease shows itself, the attacked sets should be 

 uprooted, burnt, and replaced, or the diseased rods cut to prevent 

 the disease spreading. The " Black Mauls " seem to be the chief 

 sufferers from the disease in the West. 



10. A weak solution of formalin, 0*5 per cent., may be used 

 for spraying, to kill the contents of the various kinds of fruits. 

 This is, at the best, a surface-cure for a deep-seated disease, and 

 has not, as yet, been tried in the holt. 



