DISEASES AND PESTS OF THE MAIZE CROP 419 



season after breaking new veld that weeds appear which do CHAP, 

 not grow in the unbroken veld, such, for example, as Mest- x - 

 briede, Aviarantus paniculatus. This particular weed is 

 greedily eaten by mules and other stock ; the seeds are hard 

 and pass through the alimentary tract undigested, ready to 

 germinate with the first favourable opportunity ; if the drop- 

 pings of the mule or ox fall on land newly broken, the Amar- 

 antus seeds become buried in the loose soil and a seedlino- 

 soon follows the advent of favourable weather; but if it falls 

 on hard, unbroken veld, the probability is that the Amarantus 

 seed will be picked up by a seed-eating bird ; or it may lie on 

 the hard ground, sprout with the rains, and fail to grow into a 

 fully-developed plant because the soil is too hard for the roots 

 to penetrate quickly, and in the meantime the grass and other 

 veld plants choke it. 



The seeds of other weeds, such as the sweet-grass (Chloris 

 virgatd), are carried by the wind and scattered broadcast over 

 the veld ; they do not grow readily in the unbroken veld be- 

 cause the soil is too hard. But they will grow readily in loose, 

 washed soil deposited along the roadsides, and soon develop 

 seed ready to be blown across to any newly-ploughed lands in 

 the vicinity. A few plants along a roadside will soon supply 

 enough seed to cover whole fields. 



Blackjacks and burweed are carried on the legs of the 

 mules and oxen which plough and work the land, or which are 

 turned into the waste lands to eat down the stalks. These 

 animals also spread weeds such as stink-blaad (Datura), the 

 seeds of which pass through their alimentary tracts undigested. 



A South African farmer was once heard to remark that he 

 would never turn cattle into his lands to eat his maize stalks 

 because they would spread the seeds of weeds in their drop- 

 pings. He might with as much reason argue that he would 

 not use a gun because people have been killed through accidents 

 with guns. Both guns and dung are necessary ; even the weeds 

 brought in by the dung are valuable if turned into manure. 



Perennial weeds, such as quick-grass (Cynodon Dactylon) and 

 uintjes (Cyperus, spp.), are spread from one field to another by 

 the plough, cultivator, or harrow, if these implements are not 

 properly cleaned before they are transported from a weedy part 

 of the farm to clean lands. 



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