4 BULLETIN 436, U. S. DEPAETMENT OF AGEICULTUEE. 



Mr. R. N. Wilson, in notes made during May, 1912, at Sacaton, 

 Ariz., relative to a small area cultivated by the Pima Indians, stated 

 that com on the Bureau of Plant Industry Experimental Farm at 

 that place had been enthely killed by these beetles before it matured. 

 Mr. Hudson, agent in charge of this farm, says that this is the usual 

 fate of the early corn planted at Sacaton, but that some years the 

 beetles are not so numerous and the com partially escapes, although 

 it is not so vigorous as it should be, on account of the beetle attack. 



Three years previous to this, Mr. C. N. AinsHe, also of the Bureau 

 of Entomology, made the following notes on his observations in the 

 same locahty: 



Heard early this a. m. that a "black bug" was destroying corn in garden. Found 

 several long rows of corn 4 to 6 inches high, almost killed by Chaetocnema ectypa. The 

 beetles were clustered on the leaves and in many cases a dozen or more would be 

 down in the center, busy with the terminal leaf. The hills looked as if blasted by a 

 hot Avind. 



Some volunteer stalks of corn 2 feet high, in a watermelon patch some rods away, 

 were bleached almost white, as was a plat of corn 2 feet high on experimental plat, 60 

 rods or so distant. These beetles are credited with doing much mischief to corn here. 



Dr. A. W. MoiTill ^ states: 



The com flea-beetle, Chaetocnema ectypa, was unusually abundant in parts of the 

 Salt River Valley, and was especially troublesome in experimental plots of Sudan 

 grass at the experiment station farm near Phoenix. 



Prof. G. F. Freeman,^ of the University of Arizona Experiment 

 Station, in speaking of variety tests of Papago and other varieties of 

 sweet corn, says: 



Small black flea-beetles (Chaetocnema ectypa) injured both lots quite severely. So 

 many plants of the early lot at Tucson were killed that all plots had to be replanted 

 about April 20. The latter planting was injured to some extent but very few plants 

 were killed outright. 



From these observations it is obvious that the injury caused by 

 this beetle is such as to demand careful attention, and vigorous efforts 

 should be made to reduce its numbers upon the ranches of the south- 

 western United States. 



FOOD PLANTS. 



It seems probable that this beetle had as its native food plant some 

 one or more of the native grasses growmg in the Southwestern States, 

 as it is found on quite a number of these. It is especially abundant 

 at different times on wild barley (Hordeum murinum), salt grass 

 {Distichlis spicata), Johnson grass {Sorghwm Jidlepense), and hair- 

 grass dropseed (Sporoholus airoides), as well as on others. Johnson 

 grass and salt grass are two of its favorite food plants, and at aU 



1 Morrill, A. W. Report of the entomologist of the Arizona Commission of Agriculture and Horticulture. 

 In 6th Ann. Rpt. Ariz. Com. Agr. Hort., p. 33. 1914. 



2 Freeman, G. F. Papago sweet corn, a new variety. Ariz. Agr. Exp. Sta. Bui. 75, p. 462. May, 1915. 



