G8 ANNUAL RKPOKTS OF DEPARTMENT OF AGRICULTURE, 1940 
TOMATO FBUITWORM 
Extensive field experiments on the tomato fruit worm were conducted 
In southern California and Utah in an effort to develop a profitable 
and commercially satisfactory control. 
In Ohio small field-plot experiments were conducted as a means of 
determining as accurately as possible the differences between the 
toxicity of calcium arsenate and that of cryolite and other materials 
against this insect. 
In southern California cryolite and calcium arsenate were used in 
larire field-scale experiments. In 5 different commercial plantings 
where experimental plots were located the insect damage averaged 
14.6 percent in the 20 untreated plots. This represented an average 
loss of 87.6 boxes of tomatoes per acre, or a monetary loss of approxi- 
mately S4')X>. In a comparable series of 20 plots to which Was ap- 
plied an undiluted synthetic cryolite dust the average loss was 3.1 
percent. A critical analysis of these results shows the saving from 
treatments with cryolite to be between 10 and 13 percent of a tomato 
crop worth on the average $300 per acre. On this basis, when the 
cost of control operations was deducted, the net return ranged from 
$20.40 to $2^X> per acre for these treatments. In similar plots 
treated with undiluted calcium arsenate dust the net return ranged 
from $11.55 to $19.95 per acre. 
Included in this series of experiments were five other cryolite- 
dust treatments and four cryolite-bait treatments. All the insecti- 
cides were applied when the first fruits began to set. and twice after 
this period at intervals of 2 weeks. The dusts were applied with a 
rotary hand-type duster at the rate of 10. 20. and 30 pounds per acre, 
respectively, for the three applications. The baits were scattered 
by hand over the plants at the rates of 40, 60. and 80 pounds per 
acre for the three respective treatments. Imported synthetic, do- 
mestic synthetic, and natural cryolite containing approximately 96, 
83, and 93 percent of sodium fluoaluminate. respectively, were used 
in these experiments, in both the undiluted and diluted forms. The 
diluted dusts were prepared with talc and contained. 70 percent of 
the sodium fluoaluminate. Although the control value of the undi- 
luted and the diluted dusts tended to a correlation with the percentage 
of sodium fluoride contained in the mixture, the differences in control 
values were of little significance. Baits containing 1 pound of 
natural cryolite to 10 pounds of coin meal and 1 pound of natural 
cryolite to 10 pounds of bran were approximately as effective as the 
cryolite dust. A bait mixture containing sawdust as a carrier was 
definitely inferior. 
In a series of exj>eriments where the cryolite and calcium arsenate 
dust mixtures were applied with power dusting machinery the dif- 
ferences in the control obtained with the six types of cryolite dusts 
used were LeSS pronounced than in the series in which hand machines 
were employed. However, as in the case of the treatments with 
hand machines the particular brand of calcium arsenate used in 
both these series was inferior to the cryolite dust* Twelve and two- 
tenths percent of the fruits in the undusted plots were damaged by 
the tomato fruit w<>rm as compared with an average of 4 1 -' percent 
i'i the plots dusted with cryolite and 7 percent in those dusted with 
calcium arsenate. 
