AUHli ll/rUBAh Al'IMUUMUATIo.S MH.U lirJ4, 311 



J)i)ct«)r lloUAKi). Tluit is «l(»iM» l)v tlir Stall' ('iiioiiuilo^tNU, U>m>me 

 extent. 



Mr. Walton. Ye>, i.> ^oiiir slight .xuni. 



Doctor lIoWAKi). Tiic (iHKiaU an- all aii.\i<iii>> altoiit it tlnTr uru 

 tlicy not f 



Mr. Wai/ion. Yo.s. 



Mr. lit ( IIANAN. Have you ever«^ot a parasiti- lliat iirovi'd a -.in<i',-,> 

 against ai\y of tlu'.se injurious insects or l>u;4s. or wiiatever \ou call 

 tlieni '. 



Doctor How VIM). Oh. yes; a ^reat many times. 



Mr. Bi « MVN.VN. That provcnl a succi'ss ^ 



Doctor Howard. A perfect success; y<*s. 



Mr. Andkkson. Wlial do you mean when you say "a [lerO'ct 



SUCCi'SS '. 



Doctor HoWAHl). ll ahsolutely controls the insect 



The most famous one is the Australian Lady Bird, to kill off the 

 white scale in California. That scale made its ai)j)earHnce through 

 Ix'infx introduced accidentally into countries all over the world. 



It always caused alarm. an<l they have sent to California for the 

 Australian insect and it stop|)ed the damage. 



I ^ot a letter to-day from south France which says that scale is 

 distributed alon<; the Kivi(>ra. an<l the insect we sent over there to 

 fi»;ht has done perfi'ct work. 



Doctor Ball. Take our native insects, like the fjrass hopper. 

 Ninety per cent of the c(Mitrol work is due to narasites. After you 

 have a plaijucv 90 per cent of the et;<:s have often neen found destroyed 

 by parasites. If it was not for parasites, our native insects would be as 

 serious a pest as new ones, and that is why the new ones are a very 

 serious pest, for they leave their parasites behind them, and are 

 brought in alone. Our native insects, in many cases, are not so in- 

 jurious, because they naturally develoj)ed a sullicient number of para- 

 sites to keej) them in check. 



Doctor Howard. I have seen 90 per cent of the e^gs of the Army 

 cotton worm destroyed by parasites. 



Doctor Ball. You have seen outbreaks of the (-aterpillar in the 

 northern country that stripped the leaves off the trees. The ne.xt 

 year there will not be one. oecause the paiasites wiped them out. 



Mr. Bi"( IIANAN. I have seen them to a limited extent. It nuiy be 

 that parasites hold them down. 



Doctor Ball. Plant lice are regularly controlled by parasites, and 

 if It were not for these parasites we would not have anv plants left 

 at all. 



D(Htor How ARD. You refer to imported parasites ? 



Mr. Burge-ss has pointed out that the range of the brown-tail 

 moth has been reduced by .several thousand s(|uare miles, and that is 

 partly due U) the work of the parasites we brought over from Europe, 

 irom 1905 to 1910. This natural method of control is fascinating, 

 because it is so cheap. 



Mr. BrcHANAN. ^es: if we can get it. 



Mr. AxDKRsoN. Take up the next item on page '12{\: the spread of 

 the Mexican bean beetle. 



Doctor Howard. Mr. Graf. 



