UNITED STATES DEPARTMENT OF AGRICULTURE 
Vy, BULLETIN No. 416 ¢ 
~ 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. PROFESSIONAL PAPER. January 29, 1917 
THE RED SPIDER ON COTTON. 
By E. A. McGreeor and F. L. McDonoveu, 
Scientific Assistants, Southern Field Crop Insect Investigations. 
CONTENTS. 
Page Page 
Zonal distribution in the Southeast.......-. Ze SOASONAL HISTORY veya seis Noo een ogee 23 
Classification and Synonymy ......-......-.-- SR MMDISPEESION Seiki, 6a NC Res Na sMeme hes ees Oe 27 
SP TeOVSES OVEN GN Shh eas Ces pe ered er ae AP Climatic Controle cas: wee nN ee 33 
Mite-HishOny SUINMANY sano ee ae 5 | Insect enemies of the red spider.........__.. 34 
Woescriptionvand habits). 252222... ab... tbe On Apicaliswarming: cussne ss el eee he ate. 58 
Nature and extent of damage to cotton in Remedial measures. ........- BAS ear Se (ae aes 59 
ROP SOME NN esc M eee ia ae at ea et 20 | Summavy and recommendations...........- 67 
Generations of the red spider............-.-. PAL 55 Yop UCo vig #2) oy Oy Ayala pas U Oe ala GU Eae esa tistea 69 
The common red spider, Tetranychus bimaculatus Harvey, is very 
generally distributed in the United States. The map (fig. 1), which 
contains 297 records of occurrence in 34 States, shows the distribution 
of the majority of reported cases. 
The species first became conspicuous as a pest to cultivated crops 
in New England and the Northeast. The early complaints related 
largely to greenhouse and dooryard plants, and it was not until 1855 
that Glover reported some injury to cotton by the pest. As settle- 
ment moved westward, records of occurrence from the Middle West 
and, finally, the Pacific Slope, appeared in our literature. With the 
exception of an outbreak in Louisiana, reported by Prof. H. A. 
Morgan in 1893, severe occurrence of the red spider on cotton had 
not been reported until 1903, at which time complaints of damage 
came from South Carolina and Georgia. In 1904 Mr. E. S. G. Titus 
(1905, a, 6), then of this bureau, found severe infestation in fields 
about Batesburg, S. C., and the following year he reported severe 
injury in North Carolina, South Carolina, Georgia, and Alabama. 
Since then the additional records of Dr. F. H. Chittenden and 
Messrs. G. P. Weldon, D. T. Fullaway, E. L. Worsham, H. F. Wilson, 
Note.—This bulletin is of interest to those who are subjected to loss or annoyance by the red spider. 
54380°—Bull. 416—17—_1 
