DISEASES OP PLANTS. 551 



It was found that the bunt spores after passage through the digestive tract 

 had for the most part lost their power to germinate, except in the case of the 

 swine. The death of the spores was apparently caused by the acids of the 

 digestive fluids. The high degree of fluidity present in the digestive tract also 

 hindered the germination of the spores. The -excreta as such, indeed, injured 

 the viability, but in none of the experiments was the ability of the spores to 

 germinate completely destroyed. 



The investigations showed that in practice there was no danger of bunt 

 infection from the use of manure from animals which had eaten smutty food. 

 It is also claimed that bunt spore balls lying on the ground in the fields can 

 resist cold, drying, and dampness for two years without losing the power of 

 germination, but that when these spore masses are broken up during the 

 reseeding of the fields to grain their ability to produce mfection would depend 

 upon the dampness of the soil. 



The enemies of oats, D. Brocq-Rousseu and E. Gain (Les Ennemis de 

 UAvoine. Paris, 1910, pp. XlV+lSk, pis. 24). — The authors discuss the fungus 

 and insect enemies of various species of the genus Avena, especially those of 

 economic value. The subject matter is treated under two heads, viz, enemies 

 which attack the plants during the growing period and those which infest the 

 grain after it is harvested. 



Figures, brief descriptions, and synonymy citations for each species are given. 

 A bibliography is appended. 



" Take-all " (Ophiobolus graminis), A. E. V. Richardson (Jour. Dept. Agr. 

 So. Aust., IJf {1910), No. 5, pp. 466-471). — Attention is called to a serious out- 

 break of this diesase in certain sections of South Australia, in which the wheat 

 on areas of from 1 to 50 acres suddenly contracted the disease to such an ex- 

 tent that not even one bushel per acre was harvested. Most of the wheat plants 

 died outright, while other cereals were free from the disease, especially oats. 



The disease appears at all stages of growth. If the attack occurs just before 

 the stalk is formed, the leaves gradually turn yellow and the plants shrivel up 

 and die. At other times it attacks the wheat after it is in head, when the head 

 suddenly whitens as if blighted, and the entire plant dies. 



The disease attacks wheat, spear grass, and barley grass, usually occurring 

 in circular patches, and in all cases the affected plants show a black incrustation 

 on the basal portions of the stem. It occurs on all types of soils, and on new 

 as well as on old land. 



Burning the stubble has resulted in crops free from take-all, but it is stated 

 that the best method of control is to starve it out by alternate fallowing and 

 cropping with oats, in a 5-year system of rotation, with wheat as the first and 

 fifth years' crop. 



The late blight of celery, S. S. Rogers {Calif ornia Sta. Bui. 208, pp. 83-115, 

 pi. 1, figs. 18). — This paper covers the work done on this disease {Scptoria 

 petroseli/tii apii) by the station during the past 4 years, including the observa- 

 tions and results of experiments conducted in the celery fields of Orange County 

 during the season of 1909 and the spring of 1910. 



After a brief description of the methods used in growing celery, the author 

 gives the history, distribution, and appearance of the fungus, together with the 

 methods used for its control. As a result of investigations it is recommended 

 that a 5 : 6 : 50 Bordeaux mixture be used at the rate of 30 to 40 gal. per acre 

 when the plants are small, the amount to be increased as' the plants grow until 

 not less than 100 gal. per acre is used on plants 15 or more inches tall. The 

 seedlings should be sprayed at least twice, and again not later than 6 weeks 

 after transplanting into the field, or earlier if blight is noticed. Spraying 

 should then be done once a month until the seasonal rains or heavy fogs come; 



