70 PROTECTION OF PLANTS — 1922-23 



Smomarj. 



Peony plants in this district are subject to at least seven distinct diseases. 

 The most troublesome disease being the Septorial leaf spot. 



Contribution No. 17, Dept. of Botany, Macdonald College, Que. 



Plate II. 



Fig. 1. — This shows lesions believed to be caused by an undetermined 

 Phyllostida. The spot at A is very typical. The others are somewhat larger 

 and more irregular than usual. The spots developed in the field after a moist 

 period o some days and this perhaps accounts for their large size. 



Fig. 2. — A close up view of the Septoria spots included in the outlined area 

 in Fig. 3. 



Plate III. 



Fig. 3. — A leaf infected with Septoria paeoniae var berolinensis. 

 Fig. 4. — A plant with a disease of underground parts and lower part of stem. 

 Fig. 5. — The same plant after it had been kept under a bell jar for some 

 time showing the stem overgrown with a Fusarium. 

 Fig. 6. — Septoria spots on stem. 



COMBINATIONS OF DUSTING AND SPRAYING MATERIALS. 



by 

 George E. Sanders. 



The reactions that take place between the various chemicals used in dusting 

 and spraying are not as yet as thoroughly understood as they should be. 

 In the short space allotted it is impossible to give more than a brief sketch 

 of each beneficial or injurious reaction that has come to my notice and to 

 outline a few of the desirable and andesirable combinations. 



Copper Compounds. 



One of the best known reactions is that of lime on copper sulphate in the 

 making of Bordeaux. When just enough lime is added to a copper sulphate 

 solution to neutralize it, we get a precipitate of basic copper sulphate. As 

 more lime is added we get a series of double copper calcium sulphates, each 

 more basic than the last. When around five parts of lime to one of copper 



