l4 



THE A-GRICULTUFvAL NEWS. 



Maecii 22, 1919 



?ih:i'\ DloZASZS. 



OB3F.P-VATIONS ON SELWORM (UFRA) 

 DISEASE OF RICE 



In viir.v of the uivesiigit: >n now proctediDg of the 

 eehvorDi (neraato.ie) disease .: coco-nuts in the West 

 indies, the following observations reported by I>r. E. J. 

 Bnllet (Scicnttjic R-nxn-ly of the Aiji'iviUtv ral, Re- 

 f^earch Inxt'dul'.VvLsa, lOlT-L^Oon the conditions under 

 ■which the related pest of rice cm ascend the .stem, are of 

 3r.lercst. lU-ceni obse^rvatiotis seem to indicate that in 

 the coco-nut disease, inflection taices place among the 

 ■\'nuDg leaves and not by way of the roots: — 



Evidence was obtaiued boili ia pot cultures at Pusa and 

 5n a field experim-nt carried out in coUaHnratioc with the 

 IBciitai Department on Dacca farm, that this disease can be 

 pomeiinies conveyed by seed from an infected cio|). 



The laboratoiy work at i'lma during the past season wa^^ 

 greeted cLiefly to a study of Ihe coiiditions which enable 

 tfv induce the parasitic eel worm {Tyknchis mtgusfiis, Butl.) 

 4o leave the water of the paddy fields, and ascend the plant 

 to rea<-sh u.-; susceptible portion near the apex of the shoot. 

 la last yeai's report i'., was explained that atmospheric 

 lumicliiy around the plant was the determining factor, the 

 •worm being unable to move out of water except at high 



iuniiditips. 



The exact measure of the humidity of the air on the sur- 

 lace of a plant is exceedingly difficult to ascertain. It is, how- 

 cv„i '•.•cEsib!.; to gjovr paddy in enclosed chambers, and nieas- 

 Tiret'he relative humidity of the air within the chamber It is 

 also pf>ssible to watch the luovpments of worms on glass 

 slides kept in similar chambers. By these methods, using a 

 3X)lvni?ter. it was found that the worms can move freely 

 •when kept on glass slides at a relative humidity of 95 

 ^temperature 87° to 90° T.), but not all at "JO, the exact 

 point being apparently near 9.S. On the living plant they can 

 move at lower air humidities, certayily below 90 but not at 

 ?y, at the tame temperature. If they can soon reach the 

 Snner f^lds of the shoot (which is noly possible in young seed- 

 tlings), they become k^^s dcpendenton high air humidity than 

 vhcn they remain on thee>pos((l surface, no doubt because 

 ihe vapour of transpiration causes the confined air within 

 the folda to reach higher degree saturation that that of 



the surface. 



Temperature also iufli.iences movement, but less regularly. 

 Tor instance, vorms when free in water are much more 

 Pluggish at I'd" than at bS' i".. provded they have uot fed 

 Recently, but active, well-n'juri.-ihed worms, taken dirt^ctly 

 after feefling, show little ditference in motility at the two 

 reinperatures. At low tempcr^itures there is ordinarily little 

 tendency to a,Hcend shoots projecting out of the water, even 

 when the air is approximating to saturation, but here again 

 freshly fed worms seem somewhat more active than those 

 that have been dried for some time. 



l.,ight is also a factor, but the results so far obtained 

 require further testing. 



Starvation is a factor of great injporUnce. Ju one 

 experiment two batches of 'JO worms were plac(d in drops of 

 water on slides in a saturated atmosphere, one batch contain- 

 jtigonly worms that ha<l not ftd for 18 days, ih^ oiiiijr, worms 

 tAken after they bad arrbss to living young paddy who .ts. Tn 

 24 hour? all but 4 of the former l>at«h had left ihe water 

 and were wandering fndy in the chamber, when-as in the 

 ether bafb. r.one h;id left, the drop. Four days later only one. 

 waqleft in the first drop, while 19 were still in the second 



Hence amongst the factors which ciuirol t.ue wander- 

 ings of the worm in search of food that it can only obtaia. 

 from the living padi^y plant, some, such as humidity, are abso- 

 lute, in that they impo.se conditions which rigidly limit thw- 

 {lower to move, while others are relative, iu that they acU 

 through the instinctive or other vital processes of the worm, 

 and so influence its movements indirectly, and are more- 

 variable in their action. 



VELVET BEANS AS A STOCK FOOD..* 



In the AyriA'idtimd News, \' ol. XVI. p. Sl6, there 

 was a notice of a paper, read before the St. Kitts Agri- 

 cultural and Gomiuercsial Society by Mr. K. E Kelsick 

 as to the value of velvet h'is.ns (St. izolohimn sp.) for. 

 stock feeding. Since then enijuiri(;s have beeiv 

 made at this r)epartrnent with rei,Mn] to qunntitieB- 

 advisable ;is a ration to various animals. The following, 

 taken from Farmeri< Bidbdin, Jtti2. United States 

 Depai'fcment of Agriculture, is of interest in this con- 

 nexion. 



With dairy cattle at the Tennessee station velvet-beaa 

 meal mixed with an equal amount of cotton-.seed meal in the 

 beginning was taken with a relish. Later it was rcidily 

 consumed alone as the entire grain ration. In no case, 

 however, was it fed in greater amount than 10 tti. per 

 head per day. In a preliminary test in feeding velvet-bean 

 meal in comparison with cotton-seed nreal, 9 lb. of tho- 

 former was hardly equal to 6 lb. of the latter. 



From several ex [>eriments made by -1 M. Scoft in feeii- 

 ing velvet beans for mi k production at the Florida station,, 

 the following result.s are noted. In the first experiment, with. 

 velvet beans fed in the po'-l, milk wa.s produced at 1.3-.3c. 

 per gallon, as compared with I3'7c. per gallon whea 

 cotton-seed meal was ft-dv In the second experiment, with 

 wheat bran used as a .supplementary feed, the cost of pro- 

 ducing a gallon of milk on tho velvet-bean ration wa» 

 13 7c., and with a cotton-seed meal ration, 15 0c. the 

 latter costing ■228 per cefit. more than the former. 



At the Tennessee station it was found that, with hogs, 

 velvet-bean meal (pods and beans) ciuUl not well make up 

 more than one-third the ration. Fed alone it wa> unpalat- 

 able to them. The South t'arolina .station reports that 

 pigs on a ration of two-thirds vclvet-bean meal and one 

 third corn meal iu;ide again during tho expfrimeut of 

 77 lb., an iiverage of 0-916 Ih daily, at a consumption of 

 1-68 ft), of the ration per pound of gain and a co^^t of 8"89c. 

 per U) 



M the South Carolina station a ration of two-thirds velvet- 

 bean meal and one-third corn meal was comp.ired with on& 

 of twj-thinlh soy beau meal and one-third corn meal for 

 fattening hogs. With tho former ('CS l)i. of the fee* 

 made 1 111. of grain, while with the latter 7 24 lb. 

 of feed was required per pound of gain. With the velvet-bean 

 meal the animals gained 0-9) G lb. pur day at .i cost of 8-89c. 

 per tb. With the soy I'Oan mad. thi< average gain per 'lay 

 was 0-."jlh Ih. at a i.ost of 13-97 c. pur lb. 



'I'liis (jMcstion is also referred to in the Agriculiural 

 yetVK, Vol. XVII, p. :J2.5. where the value of those pea» 

 as a food for hogs is [Miinled out. 'i'he n.-irni- velvet be.in ia 

 applied to several species of sii-colobium, wijich are also 

 d<isignaied by other vernacular naines, such as Florida 

 velvet bean. Bengal beau, etc, but all tho spocie.s seem tiv 

 possess very much the Hanie churaetcry. 



