r.fjo] DISEASES OF' PI.ANTS. 245 



ciih iiol t)(> flint iTill(>(l l)y fcrtili/ATS ov fiinj,'ici(li's, ;iii<I tlic im'spiico of root 

 knot or bij; root (U^prives even Dixie cotton ot its power of resistiince. An 

 ;i(<ount is tciven of worlv in progress on control measures in several counties. 



Bacterial wilt of cucurbits, I'\ V. Rand and K. M. A. Knlow.s {U. S. Dept. 

 Agr. liul. S2S (11120), pp. ^S, pin. Jf, figtt. 10): — In continuation of previous studies 

 (E. S. R., 35, p. 540), the results of more recent investigations are given, the 

 present paper dealing with the relation of soil and insects to the distribution 

 and control of the wilt due to ButilluH trachciphilus. 



Investigations have shown that the striped cucumber beetle (Diabvotica 

 vittdta) and the 12-spotted cucumber beetle (I), duodccitxpuuctatn) are both 

 suiiiiiier carriers and pi'obal)ly the only means of summer transmission of the 

 cucmliit wilt in the localities studied. Infection through the breathing pores 

 of the plant is said not to occur, and introduction of virulent bacteria into the 

 interior of the plant tissues is necessary for infection. It is claimed that the 

 bacterial wilt of cucurbits does not winter-over in the soil and all seed tested 

 have given negative results, indicating that the disease is not seed-borne. Con- 

 siderable evidence has been obtained which indicates that the cucumber beetle 

 acts as a winter carrier. 



In studying various isolations of B. tracheiphilus in different liosts and locali- 

 ties, the authors found a tendency on the part of highly or weakly virulent 

 organisms to reproduce their respective strains. Many, though not all, isola- 

 tions of organisms highly virulent to cucumbers were found capable of infect- 

 ing s(iuashes to a greater or less degree. Cucumbers were found the most 

 siiscei>tible host si)cH;ies and watermelons the most resistant. Cantaloui)s are 

 slightly more resistant than cucumbers, while the squash group stands next 

 to watermelons in order of resistance. 



Where the disease is likely to be severe, the authors recommend spraying 

 with a 4 : 5 : .")() liordeaux mixture to which 2 lbs. of lead ar.senate jtowder has 

 been added. I'ulling the wilted vines during the early part of the season or 

 as long as can be done without injuring the growth of the remaining i)lants, 

 it is claimed, will also assist in controlling bactei-ial wilt. Where only a few 

 pliints are grown, as in garden i)lats, screening (he hills with mosquito netting 

 will prevent the appearance of the disease through the protection aff(»rded from 

 the beetles. For control in greenhou.ses, beetles should be kei)t out if ]»ossible, 

 hut if tliey gain entrance to the house hand lucking is considered to be the only 

 reiiuHly to be in?connnended unless some fumigant can be foiuul Hint will kill 

 the be«'lles without injuring the cucumber plants. 



(Potato diseas«'s, liritish Isles] {(lard. Citron., ,'i. scr., (U! {UU'.)), \o. 1701), 

 f). I.Uh. — Owing to the jiresence of potato wart disease in Montgomeryshire ami 

 I'ehbiglisliire, the lioard of Agriculture certified the whole of these counties 

 MS infecled areas, elTective .January 1, 19120. I'l'rmissible exceptions as regards 

 |il:niting are indicated. 



I'.hickleg disease of jMitato is reported as sjneading in connection with cer- 

 tain seed varieties in all parts of England and Wales, causing serious los.ses. 



Wart resistant potatoes at VVisIey, 1917 (Jour. Hoy. llort. Soc, 43 (I'J/S), 

 No. /, pp. JJ'i-l,i2). — The continued s|>read of jiotato wart disease. Hpnclnitriinii 

 riiiloltioliiittn (('hri)xophlfictis cnilobioticd) . giving rise to fears that the whole 

 (•oimtry may iH'come infected, has stinailated ex|)eriinenlation looking to the 

 • IfVcloiiinent of resistant varieties. Descriptions are given of ai»proximately 

 •"•(• varieties more or less resistant, here classed as earl.v, second early, and 

 iiiiiin clop or late varieties. 



Diseases of Hue-cured tobacco, V. A. Woi.k and E. (!. Moss (/.'«/. .V. ('. 

 I>ept. Agr., J,o (191!)), No. 12, pp. 5-45, figs. 2//).— This account, i)repared pri- 

 marily for the information of the grower, deals with tobacco wilt (liactrrUnn 



