ACUIC'l'LTrilAI, APPROPIUATIOX niM>, 1(>24. 135 



Hil)l<' III <'>iiliii| or <TU'li>at<' llii^* iK'w niilliri'uk ui the <li.'«'Ji.>«- Th«' atjo of ii ' ■\ 



found on pine lrr«'«< provon the i|i.-<cu.'«' wu^ pn-jwiit in Mrili.Mh Coluinhiu in I' r 



to tho rnartmcnt of thr ('unodian hlisUT niHt (|iiarantin<'. 



MOSAIC ANn LEAF UOJ.L OV I'fXTATO. 



Invfwtipition.s of tho «)-falln<l cU'^onoratinn (liiw>am>M, moMair, |««af roll and to\k*'^\ 



troiiltlcH of potal(M's wliirh have hcon iti prrn^o.-w for wvcml yiiirM. mHow tl ;|» 



of n»ala«li<'M ha-s l)cconi<' the urcafi-Ht hamlicap to |)r>lato irnprovnniMit ami > is 



\om aniuially to pro<liic«Ts ihroiijihout ihf conutrv. Tln' out.MtarwIint; fcatMn* of tho 

 n»aultt* wciircd i.s tlic di.Hcovory that ai»hids aro tho miwt offortivo natural nu'ar»!< in 

 tho tranHmiHsion of thoso diHoaMo.H. In addition, it has h«K>n found hy an invoMtiirator 

 of tho Maino K\i>oriniont Station that lh«' prinoiiml ovor^vir»torin^f hoMt of tho |Mitato 

 aphis in tho rot<o, Ijisl soasons ohsorvations indioatod that hotli .ntroak and curly 

 dwarf aro closely rolatod to inos;iic and Hiinilar diwuM^'s of tho |)otalo I'iunf.H hocominjf 

 infoctod during' tho lattor part of tho ijrowin^^ .Hoason. whon further ^fro\vth has prar- 

 ticallv (••'usod. will not oxhihit anv of tho Hymptomn of imK^aic. hut tho tuhor« from 

 Huch liills will j)nMluco infoctod plant.s tho following waaon, tho diHoa.s(> lioing moro 

 jH'vort' if tho alfoctod .Mtock is planto<l in tho South. IasI Hoa.son'H oxporiinontson 

 control of mosaic hy roijuinf,' coiilirnis pr«'vious n-sidts, (fhowini; that roi;uing undor 

 ordinary (iold conditions, with mosaic planl.s in a<ljoinin>; |)lotM. will not I'roo such 

 atock from tho disoa.so, hut will tend to reduce tho porcontago of discasod plants, pro- 

 vided it is dono thoroughly and continuo<l throti^jhout tho Hoaj«)n. 



DEVELOPMENT t\I>ER AltTIKlCIAL LIGHT. 



Continuing: tho in vest i):at ions on tho offocts of tho relative lenpth of day and ni^ht 

 on plant growth, fairly extensive experiments have heen undertaken on the res[K)nse 

 of woody jV'roiuiials to this factor, especially with reference to such prohloms 

 hasis of winter hardiness, the natural distriitution of plants, and thoir Jloworii 



s[K)nse 

 IS as the 



-- - - ,.— ring and 



fruiting hahits. Application of this process to a numher of species shows that initia- 

 tion of tloworing and fruiting and other charactori.stic responses to differences in 

 duration of the daily illumination period are brought about as rea<lily with artificial 

 illumination as with sunlight. 



THE PROBLEM OF UTILIZING SUPERIOR VARIETIE.S OF COTTON. 



On account of the present organization or lack of organization in the cotton industry, 

 most of the seed is inferior, and there is no assurance of any general utilization of 

 good varieties. Methods of bree<Ung and acclimatization have been developed and 

 demonstrated, but other rofjuirements must be met if a full utilization of superior 

 varieties is to be se<ure(l. The discovery and development of a series of superior 

 varieties, including the I^ne Star, Trice, Columbia, Meade, Durango, and Acala, 

 make it possible to place the different regions of the cotton belt on new planes of 

 improved production, and all the^e varieties are being grown as extensively as the 

 available supplies of good seed will permit, but the inadeijuacy of the present systems 

 of providing annual supplie.-i of planting seed is also being recognized and methods 

 of improvement devised. Efforts are being made, therefore, to avoid the general 

 mixing of seed at the public gins, and crossing of the different varieties in the tielda, 

 which undoubtedly are responsible for the rapid and general deterioration of seed 

 stocks that tend to keep our proilucing industry on a low plane of efliciency. 



RUBBER. 



The need of developing home supplies of rubber is becoming recognized, in view of 

 tho danger of complete deijendence on the remote ICasi Indies for this essential raw 

 material. It is known that several species of rubber-])roducing jdants can bo grown 

 in the I'nited States, if practical methods of utilization can be devised. The Central 

 American rubber tree (Castilla) is considered inferior to the Para rubber tree (^Uevea) 

 for the pur]x>se of commercial cultivation by methods employed in the Kast Indies, 

 but Ciistilla may have a s]>ocial vahu- in developing rul)bor reserved in tropical 

 America. Such reserves of rubber should be available in regions contiguous to the 

 I'nited States in case of emorgoncies that migh. interfere with communication or with 

 the production of rubber in the Kast hulies. For emergency use, Castilla wouKi have 

 an advantage in yielding its latex more readily. 



