68 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



which might prove disastrous to cotton. Various grains, however, 

 will also bear watching for the purpose of locating and treating cases 

 of excessive multiplication. In a previous paper, dealing with the 

 conchuela at Barstow, Tex., in 1905, the author considered at length 

 the subject of the control of this insect in the alfalfa fields, a brief 

 recapitulation of which will suffice, in this connection. 



At both Tlahualilo and Barstow, in 1905, were notable instances of 

 the development of enormous numbers of the conchuela in alfalfa 

 fields. At the former place the bugs derived their entire food supply 

 from the stems and leaves of the plants, while at the latter locality 

 more than ordinary multiplication occurred only where an attempt 

 was made to produce a crop of seed before the middle of August. 

 Tli(J advantage is in favor of the crop used only for forage, for the 

 shorter time between the cuttings permits of the maturity of but 

 comparjitively few of the insects, and the problem to be solved consists 

 of the treatment of the nymphs and the prevention of their migration 

 to neighboring cotton fields. An uncut border a few feet in width 

 around an infested alfalfa field will serve to trap the crawling insects 

 which then may be destroyed by spraying with a strong solution of 

 kerosene emulsion. If heavy infestation be restricted to limited 

 areas of the field, hand picking of the adults by children or other 

 cheap labor and destroying the nymphs by spraying may be advis- 

 able. Gasoline blast torches have been used for destroying the con- 

 chuelas and may sometimes be useful under circumstances where no 

 vegetation except weeds or other noxious plants will be affected. 

 The longer period required for the maturity of a seed crop of alfalfa, 

 together with the abundance of favored food (alfalfa seed), affords 

 most favorable conditions for the development of countless numbers of 

 the conchuela. Great care should be exercised, therefore, wherever 

 this pest is likely to occur in destructive numbers, in^ selecting a 

 season of the year when a seed crop of alfalfa can be grown profit- 

 ably and without disadvantage to cotton or other neighboring crops. 

 In western Texas an attempt to produce a seed crop lias been shown 

 by past experience to be practicable only after the middle of August, 

 when the destructive season of the conchuela has passed. 



Field Measures. 



hand-picking. 



Extent of experiments and methods used. — In cooperation with Mr. 

 J. P. Conduit and Mr. J. A. Vaughan, manager and assistant manager, 

 respectively, of the Tlahualilo plantation, experiments were conducted 

 in July, 1905, for the purpose of determining the utihty of hand-picking 

 as a practical remedial measure against the conchuela. In this work 

 many native boys ranging from 9 to 15 years of age were employed. 



