ILLUSTRATIONS. 



PLATES. 



Page. 



Plate I. Conditions favoring the spread of the alfalfa weevil. Fig. 1. — 

 Volunteer growth of alfalfa on vacant lots in Salt Lake City, Utah. 

 Fig. 2. — Volunteer alfalfa growing along the right of way of the 

 Oregon Short Line Railway, a short distance north of Salt Lake 



City, Utah 12 



II. Hibernation of the alfalfa weevil. Figs. 1, 2. — Hibernating places 

 of the alfalfa weevil along fences and borders of fields in the 

 vicinity of Salt Lake City, Utah. Fig. 3. — One of the main irriga- 

 tion ditches in the Salt Lake Valley, a favorable hibernating 

 place for alfalfa weevils 16 



III. Injury wrought by the alfalfa weevil. Fig. 1. — One of the worst 



infested fields in the Salt Lake Valley, showing injury to the first 

 crop of alfalfa, which was left uncut. Fig. 2. — (a) Bunch of 

 alfalfa uninjured by the alfalfa weevil; (b) bunch of alfalfa badly 

 injured by the alfalfa weevil, showing growth made by first crop 

 in the badly infested fields 20 



IV. Injury wrought by the alfalfa weevil. Fig. 1. — Crop secured from 



first cutting of one of the worst infested fields. Fig. 2. — First 

 cutting from another field damaged from attack by the alfalfa 

 weevil. Fig. 3. — First cutting secured from one of the fields of 



alfalfa slightly injured by the attack of the weevil 20 



V. Field experiments against the alfalfa weevil. Fig. 1. — Street 

 sweeper in operation on alfalfa field after first crop was removed. 

 Fig. 2. — Second crop ready to cut in field on which street sweeper 

 was used June 14. Fig. 3. — Second crop of alfalfa growing on 

 field where no treatment was given 28 



VI. Field experiments against the alfalfa weevil. Fig. 1. — Wire-brush 

 cultivator in operation on alfalfa field after first crop was removed. 

 Fig. 2. — Second crop of alfalfa growing nicely as a result of treat- 

 ment given. Fig. 3. — Condition of untreated fields about June. . . 28 

 VII. Field experiments against the alfalfa weevil. Fig. 1. — Second crop 

 of alfalfa, estimated at 2 tons per acre, secured from field treated 

 with wire-brush cultivator. Fig. 2. — Fourth crop of alfalfa 

 secured from field where brush cultivator was used. Fig. 3. — 



Condition of field used as check (PI. V, fig. 3) 28 



VIII. Field experiments against the alfalfa weevil. Fig. 1. — Alfalfa field 

 after first crop was removed, severely disked preparatory to appli- 

 cation of "mudding" process against alfalfa weevil. Fig. 2. — Fol- 

 lowing the irrigation water with a drag, to puddle the weevils in 

 the mud 28 



IX. Field experiments against the alfalfa weevil. Fig. 1. — Second crop 

 of alfalfa in field treated by the "mudding" process. Fig. 2. — 

 Condition of untreated fields at time photograph shown in figure 1 

 was taken. Fig. 3. — Patch of first crop left in field shown in 

 figure 1, showing how larvae were disseminated from the first crop 

 into the field where the weevil had been killed by the "mud- 

 ding " process 28 



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