BULLETIN No. 645 {gh 
Contribution from the Bureau of Entomology 
L. 0. HOWARD, Chief 
Washington, D. C. January 26, 1918 
SOME REASONS FOR SPRAYING TO CONTROL INSECT 
AND MITE ENEMIES OF CITRUS TREES IN FLORIDA. 
By W. W. YOTHERS, 
_ Entomological Assistant, Tropical and Subtropical Fruit Insect Investigations. 
CONTENTS. 
Page Page 
Gradual adoption of spraying .........-...-- 1 | Better grades of fruit bring better prices. .... 13 
BESS OLlImMPOrtanCCecson- o.oo 0 61 oe ce 2 | Spraying scheme for controlling citrus pests. 15 
Injury to treesand fruit .........< ce Seta Zia; COSTOLS PTA yAN Gy sear eee ater 16 
“NOG aieeXc Mis aV Co) Ga c(i Bey pees ae 3, se roitsiand benetits:.2. 0. 2. ee ee ene 17 
- Reductionin size caused by insects.-........ Sali CONCIUSIONSL Ore eee See he a eee 18 
GRADUAL ADOPTION OF SPRAYING. 
Among Florida growers there have been developing during late 
years what may be called two schools for the control of citrus 
pests. One of these favors dependence upon natural enemies; the 
other, upon artificial methods, particularly spraying. The relative 
merits of these two general methods of contro] are not discussed 
here, since, as time passes, it becomes more and more evident that 
there is room for both under the widely varying conditions sur- 
rounding Florida groves. Enthusiastic supporters of control by 
natural agencies such as entomogenous fungi do not believe that the 
lowering of the grade and the reduction in the size of the fruits and 
of the yield, if any, are of sufficient importance to demand attention. 
Or perhaps the case may be stated more fairly by saying that they 
believe that it is more profitable to use no measures for the control 
of pests, contending that it pays better to grow the lower grades 
of fruit without treatment than the better grades with treatment. 
- It is interesting, however, and very encouraging to note the gradual 
adoption of a system of spraying for the improvement of orchard 
conditions by men who, only a few years before the Federal Bureau 
of Entomology began its demonstration work, believed in, and de- 
pended upon, natural agencies as the best all-round method of con- 
trol. This change has come partly through a realization that fungi 
1 
21698°—18—Bull, 645 
