Insect Pests oe Interest to Cotton Growers 



187 



the average loss from these insects in Arizona is estimated to have 

 been between 3 and 5 percent. Accordingly the total loss would be 

 placed between $420,000 and $700,000. 



The cotton square daubers are usually destructive to cotton only 

 during the month of August. The immature stages have never 



Fig. 15. — Adult tarnished 

 plant bug (natural size 

 and enlarged). 



Fig. 14. — Nymph of tarnished plant 

 bug (enlarged nine times). 



Fig. 16. — Adult cotton 

 square dauber (en- 

 larged about twice). 



been found in abundance on cotton plants. Evidently they do not 

 find the cotton field a suitable breeding place. Alfalfa fields appear 

 to be the principal source of the adults which invade the cotton 

 fields. In one instance it was estimated that there was an average 

 of one adult square dauber to each square foot of area in an alfalfa 

 field. If all of these insects in a single acre of this alfalfa were dis- 

 tributed in cotton fields so that there would be an average of one 

 per plant there would be more than suf^cient to prevent all setting 

 of bolls in from 6 to 8 acres of cotton. The insects were observed 

 in one instance exceeding 20 per plant on a few rows on one side 

 of a cotton field. An average of one of the bugs per plant is be- 

 lieved by the w^riter to be sufficient to cause maximum damage, and 

 all in excess of this may, therefore, be considered harmless. This 



