154 



Wheat Fungus. 



[junk, 



selves in possession of a variety of the common larch which 

 will prove immune to the attack of the well-known " Larch 

 Canker. 1 ' 



The Department of Agriculture, Victoria, have issued a 

 Bulletin (No. 9) containing an interesting account of a fungus. 



disease of the wheat plant which has from 



Wheat Fungus. time tQ time materially affected the crops. 

 {Opiiioboliis . ... J r 



graminis^) m that division of Australia. Until quite 



recently there have been recognised by the 



practical farmer of Victoria two distinct ailments of the wheat 



plant. One of these, known as " Take-all," arrested the plants. 



in their early growth, leaving in a short time large areas of 



miserable stunted specimens, dying off at various stages while 



still in the blade. Then, as the season advanced and the ears. 



began to appear, it was found that wheat-plants which promised 



well and had fully-formed heads did not develop grain, or, if 



they did, it was shrivelled and almost valueless. These latter 



plants were not only dead at the top, but from the root upwards, 



and, having a bleached appearance, the name of " White-heads " 



was given to this disease. 



The true nature of either of these diseases was not known,, 

 and it is, therefore, not surprising that various causes, such as 

 bad seed, want of some constituent in the soil, nematode worms, 

 (which seem to be an accompaniment of the diseases in certain 

 cases), weeds, &c, were assigned to them. 



Both diseases have recently been discovered to be due to. 

 an ascomycetous fungus {Ophiobolns graminis), and are simply 

 different periods in its life history. The actual stage at 

 which the plant succumbs depends upon its general health 

 and environments, and its ability in consequence to • resist 

 the fungus. 



The disease was somewhat prevalent in this country some 

 thirty years ago, and was known by farmers as " Straw blight" 

 and also as " Root-falling." It is also known on the Continent 

 and in America, and the black appearance of the root has 



