Rot hams ted Ex p e r i rn e n ta I Station (Contribution to the Symposium on " T h e Trend o f Progress," to be held during the Annual Meeting o f the Society in Exeter onluly 13, 1939, at a session organized by the Microbiologlcal Panel)
Thc liist 20 ycnrs linrc showii iinpnrnllclctl progress in ( a ) tlic use of, and (t) tlic rcsenrcli on insccticitlcs. ( a ) Ronrk'l lins rcccntly cstininted tlic consumption of Icnd nnd cnlciuni nrscnntc in tlic Uiiited Stntcs of hiiicricii. His figures arc (in iiiillioiis of pounds) : Lead arriciintc _... .... 1 1 .B 40 -44 Ciileicro~ orsericite .... .... 1.1 a0 .iB* -* Tho corisiiriiptiuii in 1937 w i s ciluiit one-linlf this figitre. Nr. Ikhiinn, of tlic Inipcrinl Institute, lins kiiidly cstimntcd for us the total world production of nicotiiic products (rcduccd to n brisis of 100% nicotiiic) for 1938 to hc ovcr 1000 tons, ns contrlistctl with nn cstiiiiatc of 500 tons in 1930, tlic prescnt \vorld production of dcrris root to Le 2500-3000 tons per niinuni, niid tlic total exports frorii thc firc cliicf protluciiig countries for tlircc years to bc :IS follows: 1918, 100 ; 1038, 550; niid 1938, 1100 tons. Loiichocnrpus \vns scnrccly :in nrticlc of conitiicrce bcforc 1030, but 1400 tons wcrc csportcd from Peru n i i d Briizil in 1038. I-Ioliiirin estiinntcs tlic world product,ioii of pyrctliruni in tons iis follows : 101 1 1918 I!)L'8 193s 775 7750 G:WO 14,000
Tlicrc nrc niitur~illy fliictuations in tlic quniititics of ccrtniii insecticides uscd (notnbly c:tlciuiii iirsciiritc) dcpciiding oii infcstatioii, but tlic figures g i w sonic intliciition of tlic iiicrcusc of cnbrt i n tlic cont.rol of insect 1wst.s by clieiiiicnl iiieniis during tlic lnst 20 ycnrs. 'l!liis is probnbly Iilrgcly iluc to tlic ~v~ttclifiilncss iiiid ctlucntioii ciiiii~~iiigiis initiated by n few pionccrs sonic 50 or GO ycnrs iigo, i r n d now spo~isorcd in aiuiiy coiintrics by Public llcciltli ttnd Agriculturnl outlioritks. 'l'liis tmitl of cvciits is likcly to contiauc and to /cud to 1111 iiicrcii~c, not only in tlic iisc of insccticidcs, hut in 1111 k i d s of control rind prcvcntntivc niciisiircs.
(/J) !L' Iic stciitlily iiicrctiviiig volunic of rcsciircli during tlic Iiist 20 ycnrs irpon till phnscs of iiisccticidc work Iius bccii tin outsttinding fcitturc. Although it is not to bc cxpcctctl tlint futurc rcsciircli work will sliow tlic ~u i i i e iiccclcnrtioii of oiitpiit iis ill tlic pist fcw yem, i t is doubtful whctlicr the p t k of prodaction h e yct l~ecii rciichcd. Niny iiisccticidcs a t prcsciit in usc were known prior to 191!). Ilespitc tlic discowry of IICW iiisccticitlril siibstiiiicw tlicsc older products iirc o. f grciit iniportitiico tit the prewnt iiioiiiciit, altliougli, wit11 ~onie, tliorc iirc signs tlirit thcir su1)reniiicy may ho
STOMACH POISON INSECTICIDES
'l'liorc is littlu qiicstioii of tlic ~~rcdoniiiriuica of the ursenicitl~ 11s insecticitlcs i i i i i n i i i u i l dips, I i n t l in Iiorti-
11)1!)
1!)94 1030