REPORT OF TEE DIRECTOR 61 



SESSIONAL PAPER No. 16 



Injuries to the Young, Growing Wheat. — During the last two years, samples of 

 young grain, particularly fall-sown grain, have been sent from the West, which are 

 either completely destroyed or which will not produce" strong plants. These injuries 

 may be the result of severe winters or of certain fungous diseases. 



The production of grain — the foremost industry of the Dominion — should be 

 carefully guarded from any destructive diseases, and a considerable amount of close 

 study is yet required to explain the various matters referred to. 



(b) Diseases of the Potato. 



Potato Scab. — The question of potato scab and its control has engaged a large 

 number of investigators throughout the countries where potatoes are grown. Although 

 taken up from almost every aspect, this universal disease is by no means under con- 

 trol. It is the general experience that certain methods of treatment may prove success- 

 ful in some years, occasionally for some years in succession, and yet in other years 

 prove of practically no value. Although potato scab cannot be classed among the 

 destructive diseases, yet it causes a very objectionable appearance in badly-infected 

 tubers. During the last season, a set of experiments was carried on in Prince Edward 

 Island on some infested land kindly placed at the disposal of the Division by Dr. 

 Andrew MacPhail, himself a successful potato grower, but, notwithstanding every 

 care, none of the efforts made proved of any value. The experiments will be con- 

 tinued, some features observed indicating the desirability of certain new lines of 

 inquiry being followed up. Meanwhile, the use of sound tubers and the proper disin- 

 fection of them, and the selection of land which has preferably not been used for 

 potatoes before, or at any rate which has not borne a scabby crop, seem the only rules 

 which afford any safeguard. 



Bhizoctonia Disease. — This is another disease affecting the plant through the 

 tuber. The disease-causing organism, while known, has not yet been well studied. 

 There are still important biological features concerning it of which we know little, 

 and further researches are necessary. In any disease where the soil serves as a medium 

 of propagation, there exist serious difficulties in the way of a lasting control. At any 

 rate, our present means of soil sterilization are practically uselesb, and rotation does 

 not effect the desired purpose. 



Storage Rots. — The rotting of potatoes when placed in storage has been very 

 considerable during this year. During their investigations the inspectors examined 

 some 20,000 bushels, or more, of stored potatoes, and found on the average a loss 

 amounting to 15 per cent ; in some single instances over 30 per cent loss was found due 

 to this cause. The question of the control of storage rots involves careful study of a 

 large number of common diseases affecting the growing plant, and, incidentally, the 

 tuber; further, mechanical injuries when digging potatoes, frost, and last, but not 

 least, the conditions under which the tubers are being stored, are closely concerned 

 in producing storage losses. While it is generally correct to suggest that storage 

 losses will be considerably reduced when these latter factors are eliminated, yet it 

 will be realized that the problem as a whole cannot be satisfactorily solved as long as 

 we fail to control the various diseases and causes themselves. 



(c) Diseases affecting Fruit. 



Silver Leaf. — Much progress -has been made in the study of this disease. Curiously 

 enough, the fruit-growers are still somewhat slow to recognize its true nature. It is 

 one of the slowly-developing, slow-killing diseases as yet little known by its symptoms, 



