8 The Bulletin. 



especially favorable for these insects. For example, long-continued 

 spells of damp, cloudy weather, improper rotation of crops, improper 

 tillage and unfavorable location of seedbed. It will readily be seen 

 that some of these causes which produce destructive insects are under 

 the control of the farmer, while others are not under his control. 

 But such insects as are due to weather conditions are, fortunately, 

 mostly susceptible to direct remedies. Pests belonging to this second 

 class are discussed in detail under the heading, "Insects Occasionally 

 Injurious to Tobacco" (page 46). The third class consists of a 

 variegated assemblage of insects which are normally found in the 

 tobacco field every year, usually, however, not in such numbers as to 

 be really a serious menace to tobacco culture. Fortunately, they, for 

 the most part, succumb to the same treatment that the farmer should 

 use for controlling the more injurious insects. This third class of 

 insects is discussed under the heading, "Lesser Insect Enemies of 

 Tobacco" (page 59). To these three sections is added a fourth, on 

 "Insects Injurious to Stored Tobacco" (page 66). 



Acknowledgments. 



The writer finds himself under obligations to a vast host of friends 

 and coworkers, to all of whom he wishes to express his thanks. He 

 finds himself under obligation to a large number of successful to- 

 bacco farmers who kindly made replies to a circular-letter sent out 

 the past spring. In this way much valuable information was gained 

 concerning insect pests in portions of the State which he would have 

 been unable to visit, and, in addition, much valuable information 

 regarding local practices used in the control of insect pests was 

 secured. The writer takes this occasion to thank each and every one 

 of these gentlemen. 



The author finds himself indebted to the writings of Howard, 

 Quaintance, Garman, Sanderson, and others, for many valuable 

 points in regard to the life-history of tobacco insects. In as far as 

 possible all these points have been verified for North Carolina condi- 

 tions. 



We are especially under obligations to Mr. W. J. Webb, of Stem, 

 Granville County, for many valuable observations, for his kindness 

 in placing his entire farm at our disposal for experimental purposes, 

 and for the actual carrying out of many of the experiments them- 

 selves. 



To Mr. A. C. Morgan, of the Bureau of Entomology, we are espe- 

 cially indebted for many valuable suggestions. To Mr. C. S. Brim- 

 ley, of Raleigh, for data regarding the life-histories of various insects 

 discussed in this Bulletin, and lastly to Mr. Franklin Sherman for 

 continued aid and advice and for the kindness of placing at our dis- 

 posal the office records covering a period of eight years. 



