TABLE OF CONTENTS. 



INTRODUCTION. 



PAGE 



Relative and absolute diseases 1 



Etiology 1 



Physical causes of disease - - 1 



Chemical causes of disease 2 



Parasitic causes of disease ---------- 2 



Symbiosis -------------3 



Antagonistic symbiosis .-..-.-.-. 3.4 



Mutualistic symbiosis ----------- 3-4 



Therapeutics 6 



Surgical treatment 6 



Vegetable surgery 6 



Methods of destroying parasites by the naked hand 7 



Picking and catching - - - - 7 



Traps and baits ------------7 



Chemical treatment ..---------8 



Curative treatment ..-_.--.---. 8 



Anti-crj^ptogamic substances or fungicides 8 



Examination of curative agents -------- ^ 8 



Action of chemical products on parasites ------- 8 



Action of chemical products on plants -------- 9 



Liquid products 9 



Gaseous products 9 



Indispensable properties of the chemical agents 10 



Methods of using chemical products in treating the diseases of plants - - 11 



Underground treatment 11' 



Aerial or above-ground treatment by gases 11 



Clochage ------------- 12 



Scalding or treatment by boiling water 12 



Use of chemical agents in the form of powder 12 



Use of chemical agents in the liquid form ------- 12 



External treatment .-.-------- 13 



Internal treatment ..--.------ 14 



Prophylaxy ------------- 15 



Therapeutic prophylaxy ---------- 15 



Preventive surgical treatments --------- 15 



Preventive treatment by means of chemical agents 16 



Preventive summer treatment --------- 17 



Hygienic prophylaxy ---------- - 17 



Growth stimulants 18 



Nutrition 18 



Exhaustion of the soil ----------- 19 



Choice of species 20 



Meteorological influences - 20 



United efforts to exterminate injurious insects, fungi, and weeds - - - 21-22 



