20 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



2. In the same field two plants upon which 4 and 3 adult conchuelas, 

 respectively, were found, neighboring plants in all directions, being 

 free from the pest at the time, were found to be injured to the extent 

 of 7 bolls out of 15 examined, and 18 bolls out of 20 examined, respec- 

 tively, while as a check the bolls on the next adjacent plant in the row 

 to each of the foregoing were examined and but 3 injured bolls were 

 found out of a total of over 30. 



3. The injury to the bolls which has been described as due to plant- 

 bugs was invariably found in sections of a cotton plantation com- 

 prising 27,000 acres, where the conchuela was also found; but in a 

 section where no plant-bugs could be found, although careful search 

 was made for them, no injury of this kind was observed. 



4. Cage tests, consisting in the confinement of several adult con- 

 chuelas on two plants in a field where no plant-bugs of any kind 

 could be found and where an examination of many bolls indicated 

 entire absence of the supposed plant-bug injury, resulted in 20 bolls 

 of a total of 34 on the caged plants showing the injury a few days 

 later when an examination was made. 



AMOUNT OF DAMAGE TO COTTON BY PLANT-BUGS. 



It is very probable that each year since cotton has been grown in 

 this country certain localities have suffered from injuries by plant- 

 bugs to the cotton bolls. The cotton stainer {Dysdercus suturellus) 

 for many years has been the most serious enemy with which the grow- 

 ers of Sea Island cotton in Florida have had to contend, and the same 

 pest Mr. Schwarz in 1879 (1. c.) declared to be the most formidable 

 enemy of cotton culture in the Bahamas, making questionable the 

 possibility of continued cotton growing on those islands. Professor 

 Sanderson's reference to the damage by the leaf-bug (Calocoris rapi- 

 dus) shows this insect to be capable of considerable destruction to 

 cotton bolls, although no estimate of the amount destroyed has been 

 made. 



In the Laguna District of Mexico — the leading cotton-growing sec- 

 tion of that Republic — the conchuela accompanied by related pests 

 of less frequent occurrence has been more or less destructive to cotton 

 during the past few years. A specimen of the insect named was sent 

 to this Bureau in August, 1902, from Mexico, by Dr. A. Duges with 

 the note that it was injurious to cotton at San Pedro de la Colonia, 

 Coahuila, Mexico. In 1903 the same pest attracted considerable 

 attention on account of its unusual abundance in the cotton fields of 

 the Laguna District, particularly those near Tlahualilo, a settlement 

 located in the State of Durango about 50 miles from San Pedro de la 

 Colonia. After investigation by the author it was conservatively 



