June 1896.] 



INJURIOUS INSECTS AND FUNGI. 



41 



In infested corn crops, frequent horse and side-hoeing would 

 be of advantage. Soot and lime hoed in might check the grubs. 

 Hoeing and hand-picking should be adopted in garden crops, 

 especially in asparagus beds, which are often seriously injured 

 by cockchafers. In the case of asparagus, a pick must be used 

 to work among the roots. 



Rooks, starlings, plovers, and gulls should be encouraged, as 

 they all are destroyers of the grubs. Moles and shrewmice feed 

 upon them, and both of these animals should be protected. Bats, 

 owls, and night-jars clear off quantities of the cockchafers flying 

 heavily in the twilight. 



Attempts have been made in France and Germany to destroy 

 the cockchafer grubs by infecting them with fungi — Botrytis 

 tenella and Isaria densa ; but the results are not on the whole 

 satisfactory. Infection is communicable by means of living 

 infected grubs, but not by dead ones, and it is obvious that it 

 would be difficult to communicate infection rapidly and exten- 

 sively among grubs living entirely underground, and not 

 necessarily in community. 



Potato Scab. 



A note has been recently communicated to the French Academy 

 of Science by M. Roze, relating to some investigations he 

 has made as to the origin of the American potato scab, in 

 which he draws conclusions somewhat differing from those 

 formed by the American experts, Dr. Thaxterand Dr. Bolley, the 

 former of whom attributes this disease to one of the mucedines, 

 or moulds, which he terms Oospora scabies, and the latter to a 

 bacterium which he has not named specifically, but which he 

 believes produces the more deep-seated little cavities in the 

 pustule-shaped abrasions which cover scabby tubers at harvest 

 time. 



M. Roze had at his disposal some potatoes of the variety known 

 as " American Wonder," attacked by scab which, as he remarks, 

 is developed solely on the surface of the tubers ; and he quickly 

 discovered that the only way of studying this affection is to 

 trace it from its commencement. As it had been already esta- 

 blished in the United States that a scabby seed-tuber communi- 

 cated scab to the tubers springing from it, M. Roze filled two 

 pots with earth and planted in each pot a scabby tuber, together 

 with seven or eight small tubers of the early variety Marjolin, 

 which were perfectly sound, having been just dug up, in order 

 to ascertain whether they would be infected by the scabby 

 tuber, as had resulted in similar experiments in America. At 

 the end of a month it was noticed that there were small brown 

 spots upon the surface of the Marjolin potatoes, and that under 

 these spots there were little whitish excrescences, or growths, 



