BUEEAU OF ENTOMOLOGY. 217 



was devoted to the study of the parasites of the weevil and the 

 relation between the control exerted by these insects and the various 

 cultural practices that are followed in the infested region. Special 

 studies were made to determine the relations between the spacing of 

 the plants and the date of thinning and weevil injury. 



The usual work was done by the agents of the bureau in deter- 

 mming the spread of the weevil during the season. As a result a 

 map was published in the fall showing the progress of the insect, 

 for the use of State officials concerned in quarantin3. 



An agent was stationed in Arizona to study the cotton weevil 

 closely allied to the boll weevil which was discovered in that State 

 a few years a^o. It was found that the Arizona weevil will attack 

 cotton and did so in the case of experimental plantings. It was also 

 found that this weevil had a very surprising ability to withstand 

 arid conditions. In fact, it is quite possible for it to live in a semi- 

 dormant condition for an entire year. If this weevil were introduced 

 into western Texas, the conditions would undoubtedly be favorable 

 for its propagation and this would interfere seriously with the de- 

 velopment of the cotton industry in that region. 



The work on the cotton red spider was continued at Batesburg, 

 S. C, and a laboratory was established at Thomasville, Ga., for the 

 study of the numerous species of insects which, in addition to destroy- 

 ing a large amount of fruit of the cotton plant, carry the sporas of 

 certain dissases. The work upon this subject, which was in coopera- 

 tion with the Georgia State Board of Entomology, showed that the 

 importance of various insects which havs been considered minor 

 pests of cotton has been greatly underestimated. 



Tobacco insects. — Farm tests of powdered arsenate of lead as a 

 remedy for the tobacco hornworm were made on 126 localities in 16 

 counties. The experiments ware highly successful and the indica- 

 tions are that in the near future arsenate of lead will enthely supplant 

 Paris green as an insecticide for tobacco worms. 



The so-called mosaic disease of tobacco was found to be transmitted 

 commonly by several species of insects. In fact, any insect which 

 travels from an infected to an unmfected plant is likely to convey 

 the disease. It thus becomes necessary to pay considerable attention 

 to a number of species which have been considered minor pests of 

 the tobacco plant, as it appears that the damage that they may do 

 in conveying the mosaic diseas3 is considerably more important than 

 the direct injury caused by feeding upon the leaves. 



In experiments conducted in Florida it is shown that arsenate of 

 lead is a very much more efficient and economical poison against the 

 tobacco budworm than Paris green. As a result of local work in 

 Florida, the planters applied this discovery to an area of 700 acres. 

 In a short time it is believed that the new poison, which results in 

 the saving of several dollars per acie in the cost of production, will 

 come into universal use where the tobacco budworm occurs. 



Sugar-cane insects. — Work on sugar-cane msects was con- 

 tinued in cooperation with the Sugar Experiment Station of the 

 State of Louisiana at New Orleans. The most important discovery 

 made was in the relation between the burning of the tops of the cane 

 in the field and the abundance of the moth borer, which is the most 

 destructive sugar-cane insect in the United States. It appears from 



