UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1178 
Washington, D. C. 
November 21, 1923 
BORDEAUX-OIL EMULSION. 
By John R. Winston, Pathologist, and John J. Bowman, Junior Pathologist, Office 
of Fruit-Disease Investigations, Bureau of Plant Industry, and W. W. Yother-. 
Entomologist, Office of Fruit- Insect Investigations, Bureau of Entomology. 
CONTENTS. 
Page. 
Introduction 1 
Historical summary 4 
Laboratory test?. . ." 5 
Preparation of spravs 7 
Field trials .' 10 
Growers' experience 19 
Page. 
Spray-burn 19 
"Usefulness and limitations of Bordeaux-oil 
emulsion 20 
Bordeaux-mixture treatment of hard water. . 21 
Summary 21 
Literature cited 22 
INTRODUCTION. 
Spraying as a means of protecting Florida citrus fruits from 
parasitic diseases and insect pests has been slow in becoming a 
general practice. There are several good reasons for this. Ordi- 
narilv a salable crop of fruit can be grown without the aid of sprays, 
although properly sprayed fruit sells at a premium. Because of 
lack of thoroughness or improper timing of applications, or both, 
spraying often falls short of accomplishing its purpose, and money 
thus expended is a partial or total loss. Large operators seldom 
maintain sufficient equipment for the proper and effective treatment 
of their whole acreage. 
Many groves are abundantly supplied with entomogenous fungi 
parasitic upon such pests as scale insects, white Hies, mealy- 
bugs, and rust mites. Such natural control lessens the necessity for 
spraying. If it were not for these fungi and their beneficial effects 
or unless pest control were conducted on a basis far different from 
that of the present time, it is doubtful whether citrus fruits could be 
grown commercially in Florida. In damp locations, such as ham- 
mocks, citrus fruits of the very finest quality are grown, often with- 
out the aid of sprays for the prevention of insect attacks. In drier 
sections, such as high pinelands, or during protracted dry periods 
conditions are less favorable for the development of entomogenous 
fungi, and insect pests frequently become very abundant and do an 
enormous amount of damage before the fungi reduce their numbers, 
thus lessening the protection that the fruit grower is justified in 
expecting from them as a means of preventing loss. 
52770 s — 23— Bull. 117s 1 
