60 WM'AL REPORTS OF DEPARTMENT 0] LGBICULTUBE, 1939 
An interesting and important point learned during the progress 
of biological studies was that newly batched larvae of the tomato 
fruitworm, in crawling over the foliage of tomatoes that had been 
treated with insecticides, picked up particles of such insecticides with 
their mandibles and also cleaned off their feet by drawing them 
through ill*' oral aperture, indicating that these larvae may be poi- 
soned by insecticides without actually devouring the treated foliage 
or fruit. 
n e sparse infestations of the tomato fruitworm in northern I 
following a mild winter and a 16-percent survival of pupae in over- 
wintering cage expei emphasized the importance of the move- 
ment or migration of the moths from the South and verified the 
elusion of various worker- in Ohio, Illinois, and Indiana that t 
of the infestations of ! : '«- tomato fruitworm in northern latitudes is 
ordinarily the migration or movement of adults from the southern part 
of the count ry. Experiments with 17 different insecticides and toxicity 
with a bait and a dust mixture which were applied in ±2 different 
combinations of time of season, interval between applications, and 
number oi applications throughout the period between .Inly 11 
September L2 were handicapped because Hie sparse infestation would 
not permit significant conclusions to lie drawn on t he relat ive efficiency 
of t lie different insect icides or treatments. 
Owing to the sparse infestation of the tomato fruit worm in sout] 
Indiana, the experiments at that point did not yield significant results 
regarding the relative efficiency of the different insecticides \\-y^\. 
Tin- results of residue studies in California and Indiana led to the 
conclusion that none of the insecticidal materials w^^\ in th< 
of the tomato fruitworm which are likely to leave a poisonous residue 
on the harvested fruits should be applied within 3 week- of the first 
picking. Preliminary studies indicated that if no application- are 
made within this 3-week period no excessive residue is likely to be 
present on the harvested product. In instances where a res 
occur on the fruit at harvest time, the indications are that the was 
process in the cannery or the wiping of the fruit with a cloth or similar 
process preparatory to its marketing will practically eliminate the 
residue. 
TOMATO PINWORM 
AJthough the tomato pin worm cont inued to cause -e\ ere losses to the 
tomato crop in some fields of southern California during the summer 
and fall of 1938, such losses were not so pronounced a- in previous 
years except in certain districts where tomatoes are grown in a suc- 
cession of plantings throughout the frost-free period. Much of the 
improvement in the tomato pinworm situation is attributed to the 
activities of the growers who followed the recommendations of the 
Department by Cleaning up and destroying tomato-crop remnant-, 
which ordinarily function a- important sources of reinfestation, and 
then giving t he infested lie Id- a clean plowing. Thi- development has 
corroborated the experimental evidence obtained by the workers to the 
effect that i he el i mi nat ion of infested tomato-crop remnants comprised 
a \r}\ important item in pinworm control. 
The results of extensive tests with various insecticides, involving a 
total of 330 field plots, corroborated previously obtained information 
