298 Tin-: IlLACK WATTLI-: INDL'STKV. 



appreciated, and thoiijj'h we are still a lon<^- way from out of difti- 

 cultv in regard to pests, the knowledge is gradually accunuilating 

 which a few years ago was altogether absent, and from which 

 ultimately good results may be exj^ected. 



From the jjurely jjractical side this nuich ma}' be said in 

 regard to bagworm 1 L'halioidcs jiniodi). The bagworm belongs 

 naturally to the hot drv Thornveld. and is not at home in the mist 

 belt. 



The wattle belongs iiatnralh to the mist belt, and is not at 

 home in the Thornveld. 



Very seldom do these two velds overhi]). and it is found in 

 ])ractice that healthy wattles in the mist belt suffer much less 

 from bagworm than the usual wattles found in the Thornveld. 

 In other words, if wattles were grown only in what are properly 

 wattle areas, the trouble would be insignificant, and the farmer 

 who extends beyond that must take the commercial risk attached 

 to his venture. 



haulier, in Union . li/riciilliiral Journal. |inie-|ul\-August. 

 i(>]3, deals exhaustively with Ijagworm, and suggests shelter as a 

 means of jjrevention. Though he himself condeiuns this as im- 

 practicable, there is more in the suggestion than he seems to tliink. 

 especially as belts of tall gums put in on purpose to l)reak the 

 insect-bearing winds, do themselves grow into monex- as fast as 

 the wattle. If the gum has any jjrohibitive eti'ect upon the spread 

 of l)agworm. it has that effect without loss in the returns from the 

 ground, and with very little exti"a expenditure. 



Much alarm has fi-om tiiue to time been expressed b\- 

 growers by the presence of the disease now known as " mottled 

 disease of the black wattle." This has been carefully investigated 

 by Dr. P. A. van der Byl. and his report was issued as Science 

 Bulletin No. 4, Division of Botany, Union Government, 1914. and 

 contains much of interest. The following are the most important 

 results arrived at, viz. : — 



" The disease known as ' mottling in wattles ' is due to 

 jjhysiological derangements caused by unfavourable conditions of 

 growth." 



" Methods of control should l)e directed toward improve- 

 ments of the conditions which ])roduce the disturbance." 



In addition to all that is stated therein. I woidd add that the 

 trouble often occurs among the most healthy and vigor(nis wattles 

 as soon as they become crowded and cannot obtain sufticient 

 light or moisture. In such case thinning, even after the disease 

 shows is benelicial, though thinning a vear earlier ])revents the 

 disease, gives finer trees from what are left, and is consequentlv 

 the method tliat should be ])ractised. 



Dr. \ an ^Wr \\\\ has also produced .'mother valuable bulletin 

 on the (hsijosition of tannin in the \\attle bark'. 



