72 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



is believed that the data given in connection with the study of 

 individual capabilities of the conchuela will be useful in the deter- 

 mination of the expense a cotton grower can afford to incur for hand- 

 picking of the conchuela and other Pentatomid bugs when appear- 

 ing in threatening numbers. It may be said summarily that the 

 practicability depends on the available abundance of cheap labor 

 and on the acreage of cotton that it is desired to treat. 



OTHER METHODS OP COLLECTING BUCxS FROM COTTON PLANTS. 



In addition to collecting by hand, a test was jnade of the possibility 

 of collecting the immature conchuelas by jarring them into a piece 

 of canvas or cloth placed around the stalk of the infested cotton 

 plants. Certain modifications of this method might be useful where 

 the numbers of immature bugs on each plant is large, or where 

 machines, such as have been devised but proven unsuccessful for 

 the collection of the boll weevil and bollworm, might give good 



results in the collection of both 

 nymphal and adult stages of the 

 plant-bugs. 



CONTACT INSECTICIDES. 



Adult Pentatomid bugs, in general, 

 are known to be little affected even 

 by strong solutions of contact insecti- 

 cides. For ordinary field treatment 

 insecticides, regardless of efficiency, 



Fig. 10. — The grainhug (Pentatoma sayi): . j • i p • j i 



Nymph, first instar. Enlarged 21 di- are impractical for usc agaiust such 

 ameters. (Original.) iusccts as the concliucla. Their use 



might, however, be advisable under such conditions of excessive 

 infestation as have been described as resulting from the migration of 

 nymphs in 1905 at Tlahualilo. As suitable materials for making and 

 applying kerosene mixture were not available, a test was made of 

 cottonseed-oil soap solution, using one-half pound of soap in 4 gallons 

 of water. This was found to destroy nymphs when thoroughly 

 sprayed, but only 3 or 4 per cent of the adults succumbed to the same 

 treatment. 



TRAP CROPS AND ATTRACTION TO LIGHTS. 



Early in the season, before bolls are put on by the cotton plants, 

 a few mesquite bearing heavy crops of beans might serve a useful 

 purpose by attracting the conchuelas. For good results it would be 

 necessary that the development of the insects be carefully watched 

 and treatment applied before the first of the spring nymphs reach 

 maturity. Unless proper attention can be given, however, as has 

 been indicated in the discussion of preventive measures, it is inad- 



