820 



Third annual report of the Halle Station for experiments in the 

 repression of nematodes, 1891. M. Hollrung pp. 35). — The greater 

 jiait (tf this iN'jMdt is L;i\fii iiji t<> ;iii ijccuunt ot (•\i»fiiiiit*iit.s in de.struy- 

 iiig the beet uematode Heterodera schachtii. It has been geuenilly sup 

 ]K).se«] that the condition of the soil known as beet sickness {RUhnnnUflig 

 keit) wa.s due to or Mas at least favored by eontinuous eroi»i»ing with 

 beets, l)ut the author ineutious several cases in whieli this trouble 

 occurred in fields jilanted with sugar beets for the first time. On exam- 

 ination tin* tionble was found to be due in every case to the l»eet root 

 nematode. The autlior is unable to explain this sudden appearance of 

 tlie jiarasites, but is not intlined to believe that the worms or their larv;e 

 were introduced with the seeds or transported by the wind. 



Details are given of six field experinu-nts carried out l»y beet growers 

 under tlu; direction of the station on .some 75 acres with Kiihn's method 

 lui destroying the i>arasites by the use of liait plants {Fan<iptUinzen). 

 Owing probably to a failui'e to carry out diiections. only two of the.se 

 exi>erinients were sincessful. The history of the most successful experi- 

 ment is as follows: In iss.! ;i pint of nearly 8 acres (lli.5 Monjen) 

 wasjilauted with sft'*\ heets, wliich wen* ruin«-«l by nemat«»des: in 1.S.S4 

 rye was planted ; in isstJ ])eard«'d wheat: in 1S.S7 potatoes: in l.S.SS bar- 

 ley; in ISSM an atteinpt was made to ilear the field of nenmtodes by 

 using bait jdants, which were allowed t4» giow until infested with the 

 Morms and were then <b'stroy«'d together with tin- jtarasites; in 1S1H> 

 summer wheat was j^lanti'd: in ls;»l sugar beets. The beets were fei 

 tili/.ed with Chde saltpeter and sui>eri>hosphate; they grew well during 

 the entire season, judarized 1(1 p«'r cent of sugar, and gave a crop of 

 neaily 10 tons ])er acre. 



In the other su<(essful experiment tin- field tr«'ate<l with bait jdants 

 l)roduced about 15 tons per acre, while a neighboring field which had 

 not ln'cn baited jtroduced h'ss than (» tons per acre. 



A case is cited ( Winter landir. Zt</., IS'.H^ Xo. X?^') where a field which 

 yielded (> tons ])er acre before the use of the bait method, produced 

 nearly IS tons per acre aft^-r that method had been trit'd. 



As beets can not be planted the year the bait jdants are used, exi)eri- 

 men ts were tried in which the inlested fields weie first i»1ante<l with 

 bait jdants and afteiwards with early polat<tes in order that the ground 

 should not remain idle tin* entire year. The results t)f experiments on 

 live different farms and with ditterent varieties of early potatoes are 

 tabulated and discussed. The returns were such as to ])ay the entire 

 expeu.ses of the exi)eriments and leave a considerable margin of profit. 

 The author believes that in further trials this method will prove still 

 more successful. The general conclusions diawu from the five exp«'ii 

 mentsof this nature are: (1) The first bait should l»e jdanted Ajiril 10- 

 15; (2) it is more imjioitant that the ]>o(afoes should be hardy than that 

 they should be early; (.{) S to 1(» days should elapse betwe«n tln' time 

 the potatoes are plauted aud the second bait is destroyed. 



