179 



been conveyed by human agency or aided by down stream air 

 currents along the river. Beiri and Renmark are roughly 100 

 and 120 miles east of Watervale, and between the places there 

 is no direct traffic. Neither is there any direct traffic betweenl 

 the Renmark area and Angaston (in which area downy mildew 

 is reported) or McLaren Vale, roughly 130 miles south-west 

 of Renmark. The chance that spores would be conveyed by 

 human agency from the Renmark area to any of these places^ 

 is very slight. Yet distances of well over 100 miles are con- 

 s.iderable to be bridged by air-borne spores of the Plasmopara 

 type. This, of course, is on the assumption that it was from 

 the Renmark area that the other South Australian grape- 

 growing areas became infected. Unfortunately no reliable 

 dates can be obtained of the various outbreaks. They were 

 all reported about the same time, except the McLaren Flat 

 outbreak in February. It is possible that Mildura was really 

 the centre of dispersion for the spores infecting the different 

 areas in this State, in which case the carry of the spores would 

 be about 200 miles to 230 miles in a straight line. 



No specimens of this fungus have been received during 

 the past (1921-22) vine-growing season, although leaves from 

 a number of different localities in which the fungus was 

 present in 1920-21 have been examined. It seems probable 

 that the fungus will have difficulty in establishing itself in 

 South Australia because of the climatic conditions (Osborn, 

 1921). 



Synchytrium taraxaci, de B. and Wor. On living leaves 

 of Hyj)ochoeris glabra, L. Exceedingly common on its host in 

 damp areas. Victor Harbour, Aug. 27, 1917; National Park, 

 Oct., 1918; Tea Tree Gully, Aug., 1918, T. G. B. O. (McAlp., 

 1895, No. 2205). 



BACTERIA. 



PsEUDOMONAS jUGLANDis, Picrce. On stems, leaves, and 

 fruits of Jiiglans regia, L. This bacterial disease of walnuts 

 has, during the last twenty years, spread to almost all places 

 in the State where walnuts are grown, even to trees 10 or 12 

 miles from any other. It is impossible to get a marketable 

 crop from many trees now. Not listed by Mc Alpine (Osborn, 

 1921). 



Bacterium mori, B. and L. Causing angular black spots 

 on the Leaves of Jlorus nigra, L. (mulberry). Clarendon, Jan., 

 1921, G. S.; Mylor, Mar., 1922, T. G. B. O. Not listed by 

 McAlpine (Osborn, 1921). 



