28 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1944 
is well suited for use in aerosols. The pure pyrethrins also proved to 
be of use in the preparation of analytical standards for pyrethrum. 
ANALYTICAL AND SERVICE WORK 
Approximately 900 samples of paisceflaneous insecticides were ana- 
lyzed, most of them for other divisions of this Bureau and for the 
Foreign Economic Administration. Analytical methods were devel- 
oped for DDT, for certain dinitro compounds, and for the determina- 
tion of free lime in calcium arsenate and of sesamin in sesame oil. 
MEXICAN FRUITFLY CONTROL 
The area quarantined on account of the Mexican fruitfly now covers 
all the citrus-producing portion of Texas, but the infestation has not 
extended beyond the section adjacent to the Republic of Mexico. The 
citrus industry in Texas has had a phenomenal growth, and the in- 
spection, sterilization, and certification of the approximately 50,000 
cars of citrus fruit produced annually has become a problem of in- 
creasing importance; Although the possibility of permanently erad- 
icating the Mexican fruitfly appears to be remote, the danger of its 
spread through the shipment of infested fruit has been drastically 
reduced by the requirement that all fruit from infested zones be steri- 
lized before shipment. The amount of fruit l reated during the season 
of 1943-44 increased almost 200 percent over the previous year. A 
total of 4,263 equivalent carlots of fruit were sterilized without injury 
to the fruit and at very little additional cost to the packer. Because 
of the general adoption of the fruit-sterilization process, which was 
developed by the Department in 1929, a lengthened harvesting season 
was made possible. The harvesting season for grapefruit produced 
in the regulated area was extended from April 30 to June 15. and that 
for Texas oranges was extended to include the entire year. The in- 
festation in the regulated area developed somewhat later, than in soin- 
previous seasons. 
Tables 1 and 2 give data on the number of infestations and the 
amount of fruit sterilized in Texas since control of this insect was 
undertaken. 
Table 1. — Infestation* of Mexican fruitfly hi Texas, fiscal years 1935-1944 
Fiscal year 
Flics 
trapped 
Larval 
infesta- 
tions 
Date harvesting 
season close. 1 1 
Number 
371 
Number 
30 
April 2. 
March 31. 
1936 -- - 
256 
1937 . - : ? 
4,714 
1 , 062 
Do. 
1938 - ---- 
712 
218 
April 
i:'„t>87 
2, 141 
/May 15 (Q). 
\June 15 (O). 
April 3(1. 
ti. 157 
! 582 
979 
552 
May 31. 
244 
259 
Do. 
1943 - 
224 
291 
Do. 
1,796 
576 
/Tune in (O). 
\No closing (.0). 
'(G) Grapefruit. (O) oranges. 
2 Includes 4 infestations in 1939. 
