December, '22] hawley: sugar-beet root-maggot 389 



Canada, as well as at Bums, Oregon, and Moscow, Idaho, and that, 

 as far as he knows, the larval stage had not been observed previously. 

 The maggots also have been reported as causing considerable damage 

 locally in Idaho by Doctor Titus and in Colorado by Mr. Maxson of 

 the Great Western Sugar Company. With the exception of a possible 

 infestation in Emery County, the destructive work of the insect in 

 Utah appears to be restricted to a few townships in Cache County. 



The maggots of Tetanops are of the typical dipterous type. They 

 injure beets by feeding on the tap root. The area around the point 

 of attack turns black and the surrounding soil is saturated by the 

 leakage of beet sap. When the beets are small and feeding is just 

 beginning, the roots are often entirely eaten thru. The first indica- 

 tion of the presence of the pests is the wilting of the plants. As feeding 

 proceeds, these plants die and dry up and, by midstimmer, fields will 

 show many skips and bare spots. A. H. Bateman, a field man with 

 the Amalgamated Sugar Company, states that in 1921 three hundred 

 and forty acres were rotated because of this pest in the Lewiston Dis- 

 trict, Utah. He further reports that in 1921- there was an estimated 

 loss of 924 tons in the infested area — about 21 per cent of the crop. 

 In some places 50 to 75 per cent of the plants have been destroyed. 

 Sixty-four maggots have been found around one plant, and beets 

 surrounded by ten to thirty have not been uncommon. A single 

 larva may destroy a beet seedling and apparently three or four are 

 able to kill a beet one and one-half inches in diameter. The greatest 

 damage occurs after thinning, during the last half of June. 



The life-history of Tetanops has been under observation since July, 

 1921, when a study of the insect was first undertaken by H. J. Pack 

 and the writer. At this time the maggots were nearly full grown, and 

 in most cases had stopped feeding. They were in an inactive con- 

 dition from one to six inches from their host and at a depth of one to 

 three inches in the ground. As the simimer progressed they moved 

 deeper in the soil and when last examined in September they were found, 

 head downward, at depths of four to thirteen inches. Hibernation 

 must have occurred in the larval stage, for, when fields were first ex- 

 amined on May 15, 1922, about two-thirds were still maggots and one- 

 third were in the pupal stage. Puparia were never deeper than three 

 inches and more often they were just beneath the upper crust, showing 

 that the maggots had migrated upward before they transformed. 

 In fact, the larval tunnels were often found in the dirt. The average 

 pupal period had been determined as fourteen days, and it would seem 



