THE BEAN THRIPS. 
(Heliothrips fasciatus Pergande.) 
INTRODUCTION. 
In the State of California during the past four or five years the 
bean thrips has been reported with increasing frequency as a serious 
pest to various crops. The common name " bean thrips " is somewhat 
of a misnomer, as this insect feeds on many different crops, but is re- 
tained here, as it is well known by that name in California. That 
State, with its long, dry summer, furnishes climatic conditions un- 
usually favorable to the development of thrips, and several species 
have gained such a foothold there as annually to cause a loss of hun- 
dreds of thousands of dollars. 
In the summer of 1909, Mr. E. S. Woglum, of the Bureau of En- 
tomology, informed the author that during the summer before he had 
seen hundreds of acres of beans in southern California so seriously 
infested by the bean thrips that they had the appearance of plants 
scorched by fire; and as this thrips seemed to be increasing in num- 
bers and destructiveness it appeared to be the part of wisdom to 
obtain all possible information concerning its life history and control 
before it reached the enormous abundance of the destructive pear 
thrips (Euthrips pyri Daniel). When, therefore, the Bureau of 
Entomology established a field station at Compton, Cab, in Septem- 
ber, 1909, for the study of truck-crop ard sugar-beet insects, the 
writer planned, among other projects, to undertake as complete a 
study of this insect as time would permit. With this in mind, the 
bean thrips has been the subject of thorough investigation during the 
years 1910 and 1911. During this time, however, the insect was not 
again so destructive to beans, so that remedies with spray mixtures 
could not be thoroughty tested. Nevertheless, as the life history has 
been worked out and a large fund of information obtained on the dis- 
tribution and habits of this thrips, together with knowledge of a 
natural enemy of some promise, this paper is published at the present 
time. 
At Compton, in Los Angeles County, where the life history of this 
insect was studied by the writer, the temperature is quite cool, since 
the location is near the coast. 
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