February, 1921. 



SCIENTIFIC AGRICULTURE 



79 



condition are always external and are not inherent in 

 the seed. Pi-equent elianpinp- of seed is the remedy. 



Gussow, H. T. The Control of Potato Diseases. Dom. 

 Exp. Farms Circ. 9: 1-6. 191;"). 



Gussow, H. T. Disease free Potatoes. I'loc. .Spec. 

 Bull. Dom. Exp. Farms 75-9;i 1915. 



Gussow, H. T. Report of the Dominion Botanist. 

 Rept. Dom. Exp. Farms. 191(i-17: 40 41. 191S. 



Ho\\-itt, J. E. Potato Disease Investigation. Agv. 

 Gaz. Canada 6 : 247-249. 1919. — Leaf roll and mosaic 

 have heen found to be very prevalent in Soutliern On- 

 tario and comparatively uncommon in Northern Onta- 

 rio. Blackleg and rhizoctonia are the two most serious 

 diseases of potatoes in Nortliei-ii Ontario. An educa- 

 tional campaign lias been caiiied on to acipiaint the 

 potato growers with the disease situation in Ontario 

 and with the desirability of ol)tainiiig scd [lotatoes 

 from Northern Ontario. 



Jackson, V. W. Rusts and Smuts of Grain Crops. 

 Man. Extension Bull. 44: 1-3."). 1919.— Popular, liut 

 including results of observations and experiments on 

 rusts and smuts. — G. R. Risl)y. 



Jackson, V. W. How to spot Potato Diseases in July. 

 Man. Dept. of Agric. Circ. 52: 1-6. 1919.— G. R. Bisby. 



Jackson, V. W., and Bisby, G. R. Potato Top Diseases 

 in July and August. Man. Dept. of Agric. Circ 52: ( :{«! 

 edition) 1-6. 1920.— G. R. Bisby. 



Maeoun, W. T. Blight Resistant Potatoes. Canadian 

 Hort. 42: 129-156. 1919. 



Maeoun, W. T. Varieties of Potatoes Resistant to 

 Late Blight or Rot. Agric. Gaz. Canada 6: 331-332. 

 1919.' 



Maheux, Georges. Sprajdng to Increase Potato Pro- 

 duction. Que. Soc. Prot. Plants Ann. Rejit. 12: 43-46. 

 1920. 



McCallum, A. W. The Nature and Aims of Forest 

 Pathology. Agric. Gaz. Canada 7: 737-73S. 1920. 



McCubbin, W. A. The Diseases of Tomatoes. Dom- 

 inion Exp. Farms Bull. 35. (2nd series) 5-16; Fig. 

 1-8. 1918. 



McCubbin, W. A. Brown Rot of Stone Fruits. Agric. 

 Gaz. Canada 6 : 429- 432. 1919. — A survey was made 

 in 1918 in Southern Ontario to study the occurrence of 

 Sclerotinia cinerea. Apotheeial clusters with from 1 

 to 111 cups per cluster were found as follows — plum 

 4.1 clusters and peach 5.1 clusters per tree. These are 

 probably minimum figures as later 26.3 clusters per 

 tree were found. Blossom infection occurred at the 

 rate of 10.2'/^ in cherries, 6.i'/i in plums and 2.6';f in 

 peaches. The fungus was found in 76.5'/( of leaf curl 

 twigs. The field loss of mature fruit was found to be 

 7.9% for plums and 2.9% for peaches. On the market 

 the loss was 8% for plums and 8.5^ for peaches. 



McCubbin, W. A. Notes on Diseases in 1918. Agric. 

 Gaz. Canada 6: 433-436. 1919.— Brief notes on the 

 followmg; ^\inter injury of fruit trees; petiole infec- 

 tion of Pkiiatius aniericana by Gnomonio vencta 

 causing leaf fall; tomato rot caused by Axcochi/ta sp. ; 

 Pyropolyporus ribis on red currants; I'ahirj/oniuni 

 wilt probably due to VerticilUum ; rot of cucumbeix 

 by Bhizopus tiigricans; girdling of peacji trees in nur- 

 sery rows thought to be due to Sclerotiniu cinerea ; 

 plum fall possibly due to intense heat and drought 

 conditions: lightening injur.v to tomatoes; leaf spot of 

 peach caused by Bacierimn prnni; silver leaf of ))Iums 

 and peaches due to a mite. 



McCubbin, W. A. Abstracts of Canadian Plant 



Disease Literature. Que. Soc. Prot. Plants Ann. Rept. 

 11: 72-83. 1919.— Presents abstracts of all plant disease 

 literature pul)lished in Canada up to the end of 1918. 



Muri^hy, P. A. Potato Inspection Service. Agric. 

 Gaz. Canada 6 : 217-223. 9 fig. 1919.— Leaf roll and 

 mosaic tiie two commonest potato diseases in Canada 

 which cause "running out" of seed are carried and 

 spread mainly by seed but as yet it is impossible to 

 determine whether or not a tuber is infected. Only by 

 field inspection of the growing plants is it possible to 

 know whether or not the tuber will be fit for seed. In 

 Southern Ontario and Quebec a survey of 1,336 fields 

 made in 1918 showed leaf roll in native seed plants to 

 the extent of 15% and mosaic of 7%. As leaf roll 

 plants produce only 1/3 of a normal yield and mosaic 

 plants 2/3, the "running out" of seed here must be 

 attributed to these disea.ses more than to any other 

 single factor. To overcome this trouble disease free 

 seed must be imported and in the case of Southern On- 

 tario this comes from Northern Ontario and the Mari- 

 time Provinces. Thus the Southern Ontario grower has 

 to buy a commodity the most important character of 

 which he has no means of judging. Here the potato 

 inspection service helps both parties, its certificates 

 adding substantially to the value of the seed for the 

 seller and ensuring practically disease free seed to the 

 buyer. After harvesting a second examination is made 

 of those crops which reached tlie necessary standard 

 ill field inspection. Tuber rots and blemi.shes, freedom 

 from mixture A\nth other varieties and type of potato 

 are given attention. If satisfactory, a tag for each bag 

 or barrel is provided. 



Muriih.\-, P. A. Potato Inspection Service in 1919, 

 Agric. Gaz. Canada 7 : 308-310. 1920.— A summary of 

 the work of the federal potato inspection seiwice for 

 1919. 1,605 seed grower.s asked for and received in- 

 spection. In 1918 the fields of 3,492 growers were in- 

 spected the reduction being due to the fact that in that 

 year inspections were made voluntarily without the 

 request of the grower. In 1919 only those who asked 

 for inspection received it. In Prince Edward Island 

 the price for certified seed was 70% in excess of market 

 price. 



Nelson, J. A. Asparagus Culture. Man. Extension 

 Bull. 22. 1918.— Mention made of rust.— G. R. Bisby. 



Rankin, W. H. Efficiency Factors in Potato Spray- 

 ing. Que. Soc. Prot. Plants Anu. Rept. 11: 49-55. 1919. 

 — Discusses troubles which spraying controls and gives 

 proper methods of making and applying Bordeaux 

 mixture. Community spraying as practised in parts 

 of New York State is recommended for this country. 



Sanders, G. E., and A. Kelsall. Some miscellaneous 

 observations on the origin and present use of some in- 

 secticides and fungicides. Proc. Ent. Soc. Nova Scotia 

 1918: 69-75. 1919. 



Sanders, G. S., and A. Kelsall. A copper dust. Proc. 

 Ent. Soc. Nova Scotia 1918: 32-37. 1919. 



Sanders. G. E., and W. II. Brittain. A modified Bor- 

 deaux mixture for use in apple spraying. Proc. Ent. 

 Soc. Nova Scotia 1918: 51-61. 1919. 



Sandei-s, G. E. Apply Spraying in 1919. Fruit 

 Growers' Assoc.. Nova Scotia Ann. R.ept. 55: 110-118. 

 1919. 



White, J. II. On the Biology of Pomes Applwiafrfi 

 (Pers.) Wallr. Trans. Royal Canadian Inst. 12: 133-174. 

 Text fig. 1-2. PI. 2-7. 1919— This common, wood-des- 



