DISEASES AND PESTS OE THE MAIZE CROP 



427 



X. 



land which has become infested with is-ona seed, attention chap. 

 should also be directed towards clearing the land of the seed 

 already there. Attempts have been made to starve out the 

 rooibloem by short rotations (one or two years; with leguminose 

 or other crops ; these attempts failed to secure the desired 

 result, but demonstrated that the is-ona seed could remain 

 dormant five or six years, and that it would be necessary to 

 clean the land of is-ona seed before maize could again be 

 grown successfully. Two methods of treatment suggest them- 

 selves, and are recommended by Pearson (2) — burning and 

 the use of trap crops. (1) Burning: immediately after harvest 

 the rubbish, weeds, and maize roots should be gathered into 

 large heaps and burned on the places where the is-ona has grown. 

 (2) Trap-crops : infected areas may be sown down to kaffir 

 corn for silage or fodder ; it is essential, however, that the crop 

 be cut, and the roots ploughed in, before the is-ona flowers, 

 otherwise the kaffir corn will only tend to propagate the pest. 



393. Buy Seed-maize from Clean Farms. — As previously 

 noted (IT 388) is-ona seed may be carried on an ear of maize 

 from an infected to a clean farm. There is less likelihood of 

 its being carried with shelled maize which has been machine- 

 cleaned, but it would be safer not to take unnecessary risks 

 and to refuse to buy any seed from infected farms. 



For his own sake the farmer should not allow the harvested 

 maize ears to be laid on infected land, as they may carry the 

 is-ona seed to clean lands. 



Animal Pests of the Maize Crop. 



394. The Chacma Baboon. — In some districts of South 

 Africa, especially where rocky kopjes and kranses abound, 

 the common Chacma baboon, Papio (Chccropitheciis) porcarius 

 (Bodd.), Fig. 162, sometimes does considerable damage to 

 the ripening maize crop ; " if a herd once takes to a mielie 

 field it will not leave off its daily visits until every cob is 

 destroyed ". The general experience, however, is that baboons 

 retreat before the advance of civilization ; as closer settlement 

 takes place, and vacant farms become occupied, the pest 

 becomes less troublesome. On the open High-veld plateau 

 one does not hear of damage done by baboons. 



The baboon is a wily animal, most difficult to capture ; 



