4 TIMELY HINT 93 



gating waters; (2) to kill shallow rooted weeds and annual grasses; 

 and (3) to destroy egg deposits, larvae and pupae of insects such as 

 the alfalfa caterpillar. The summer cultivation should be done in 

 August or September when worms and feebler growth depreciate the 

 value of the cutting. The winter cultivation should be done in January 

 after pasturing the ground for available forage. Disks should be set 

 straight to avoid cutting off crowns. Specially constructed alfalfa 

 renovators and cultivators, adapted to penetrate and stir the surface, 

 are also used for the purpose. 



Alkali spots in our alfalfa have been removed by plowing them, 

 scraping away surface soil, refilling with fresh soil and reseeding, with 

 abundant irrigation, to alfalfa. 



Alfalfa should under no circumstances be pastured in the summer, 

 as close pasturage and the hot sun on naked crowns will kill many of 

 the plants. It is an excellent practice, however, to mow the small 

 August cutting and let it lie for awhile, thus at the same time cheating 

 the worms and mulching the crowns against the summer sun. In 

 September, after a short season of rest and renovation, with worms 

 out of the way, irrigation will start vigorous growth in time for one 

 or two fall cuttings. 



Pests: Gophers and the alfalfa butterfly have constituted the only 

 serious pests of alfalfa in our experience at Yuma. The gophers were 

 easily cared for by a weekly distribution of raisins, each containing a 

 small dose of powdered strychnine inserted with a penknife or tooth- 

 pick. One or two raisins to a hole are sufficient. Alfalfa butterflies 

 and their consequent broods of worms, which increase to a pest in 

 August and September, are not easily controlled. It is not practicable 

 to spray the crop with arsenicals. Close cutting of the alfalfa when 

 the worms are most numerous in August will result in the death of 

 great numbers ; but enough will remain to eat down the new growth ; 

 and in cloudy weather an army of starving worms will migrate to the 

 nearest green vegetation. For several reasons, worms among the 

 number, our experience shows that it is good economy to withhold 

 irrigating water for about thirty days, beginning August 15, resuming 

 operations in September when the worm season is past. During this 

 interval the alfalfa may be disked or renovated to good purpose. 

 The advantages of this procedure are economy of water, destruction of 

 worms by restricting growth of their food plant, and restraint of weeds 

 by lack of water and by cultivation. 



Cuttings and yield: At Yuma the dates of cutting alfalfa during 

 three years were as follows, irrigations between cuttings being shown 

 by black faced type: 



Year 1st 2nd 3rd 4th 5th 6th 7th 



1909 (1)3-24 (1)5-3 (2)6-14 (3)7-19 (1)8-24 (1)9-29 (2)11-17 

 1910 (*)3-29 (2)5-10 (2)6-9 (2)7-19 (1)8-23 (1)9-26 (2)11-26(1) 

 1911 (3)3-28 (2)5-12 (3)6-20 (3)7-27 (2)8-25 (0)9-11 (2)10-30(1) 





