4/0 TiiiRTv-FiRST Annual Report 



])oas as a summer crop in the Yuma Alesa citrus district. Other 

 citrus investigational work in progress and planned may be note«l 

 as follows : 



(a) Determining the effect of winter cover-crops on the tem- 

 perature of citrus orchards as related to Salt River Valley condi- 

 tions. 



(b) Studies in bud-selection as pertaining to the Washington 

 Navel orange and Marsh Seedless grapefruit. 



(c) Study of the ad,-!i)tability of citrus stocks used in propa- 

 gation. 



(d) "J""6 Drop" studies, as pertaining to the Washington 

 Navel orange. 



(e) Variety studies. 



DATES 



A serious outbreak of scale (Parlatoria blanchardi) in both the 

 Tempe and Yuma date orchards made it necessary to defoliate the 

 palms preparatory to "torching" for the control of the insect. The 

 ])alms were cut back in May, the entire foliage being removed 

 except a few leaves at the top which were shortened to about three 

 feet in length. This treatment will prevent a crop of fruit this 

 season ; also it will cause the postponement of important investi- 

 gational work in connection with the propagation of ofT-shoots. 



It is worthy of record that the date has been a subject of study 

 in Arizona since 1895, when the first notes were taken at the old 

 vStation Farm west of Phoenix. Cumulative evidence since that 

 time proves that the date is a most valuable fruit crop for southern 

 Arizona ; that certain varieties are particularly resistant to unfav- 

 orable weather conditions during the ripening period ; and that the 

 j)lant will succeed and produce good crops on extremely alkaline 

 soil. 



OLIVES 



In self-sterility tests conducted with twenty-four varieties of 

 olives, interesting data were secured in that a majority of the 

 varieties proved self-sterile. The work will be continued for con- 

 firmation of results and an effort made to determine the best pol- 

 lenizers or planting combinations. 



Three distinct methods of pruning being practiced at the Yuma 

 Date Orchard and Horticultural Station are producing marked 

 differences in tree growth. The trees should come into bearing 

 next year, which will add to the interest of the work. 



