14 FARMERS’ BULLETIN 674. 
COST OF SPRAYING AS COMPARED WITH RETURNS.! 
Thrips injury to citrus fruits is confined to the rind and does not 
appreciably affect the eating quality of the fruit. Except in seasons of 
unusually gross infestation no great amount of fruit is lost entirely 
by reason of thrips injury. The argument has been advanced that 
where the fruit is separated into but two commercial grades, which 
embrace everything fit to ship, as is now largely the case, thrips 
injury will have but little effect on the price. The damage thrips do 
to the trees by interfering with the functions of the leaves throughout 
the early years of growth, however, is generally overlooked. The 
following statement takes no account of this indirect injury to the 
trees, which is difficult to estimate, but merely gives the profit realized 
from producing a better grade of fruit by spraying. 
Cost of spraying one acre of 18-year-old navel orange trees. 
Labor: 
2 rodmen at $2.50 each per day, cost per acre.............-......:-2.--- $1. 22 
Driver and team at.$o per day, cost peracre.........2.2....5.2..2.0.0% 128 
Gost.of labor per acre eno plicationee 02... och ask.com cote - ie ee 2.45 
Insecticide: 
14 gallons lime-sulphur at 14 cents, cost per acre, one application... ..... 1.96 
Fuel, oil, and miscellaneous: 
Gasoline, 14 gallons at 25 cents, per acre, 3 applications.................. . 625 
Oil at $1 per gallon, per acre, 3 applications...........:/....-..<s-2-22- . 025 
Repairs and batteries, per acre, 3 applications..................-0..-.-- ah 
Estimated cost of fuel, oil, etc., per acre, 3 applications. ...............-. . 86 
Cost.of- labor permicre, so applications aeee Js. ison Se pany Sek eee 7.35 
Cost of insecticide per acre, 3 applicatgens... .. ....5.. 2. -<2ean02s on oe 5. 88 
Cost of fuel and miscellaneous per acre, 3 applications...................- . 86 
Total cost of treating 1 acre of 18-year-old navel orange trees.........-- 14.09 
Returns from sale of fruit. 
Number of packed boxes fruit produced peracre.............:------------+ 324 
Per cent of fruit raised from second grade to first grade by spraying...........-- 18 
Boxes raised from second grade to first grade by spraying.......-.--.-...-.-..- 58 
Difference in price received per box for first-grade over second-grade fruit... .. $0. 51 
Amount saved peracra by Spraying. : > Meee tte. 2 ne 8 ee ee $29. 58 
Profit from sale of fruit. 
Amount saved per acre by spraying. .. -Suaeee. 6: 2.2 Sk: ioe ee $29. 58 
Cost’ of spraying pebacres- 6... .. . ... eee oe ee eee | 14.09 
Clear gain per acre fromthe. treatments geese eo - gue 2 41s se eee 15.49 
1 The figures given upon cost of spraying are based on the Bureau of Entomology’s own spraying work 
in the season of 1911. The number of boxes of fruit given, 324 per acre, was the actual production of the 
portion of grove under experiment, and as these trees were not at their best and since 18-year-old trees 
usually produce more than 324 boxes per acre, the saving effected by spraying would tend to be greater in 
most cases. The difference of $0.51 per box between first and second grade fruit was that which was 
actually shown by packing-house returns, and practically all the grade reduction was caused by thrips 
alone, 
