426 MAIZE 



CHAP. The anatomy, and the structure and development of the 



haustorium, of Striga lutea Lour., have recently been worked 

 out by Miss Edith L. Stephens {Stephens, i and 2). 



389. Remedies for Is-ona. — Discussing this pest in 1904 

 (Burtt-Davy, 1) the writer recommended that the farmer's 

 main efforts should be directed towards preventing the seeding 

 of the is-ona plants. "This can be done by hoeing them out 

 wherever they are seen, before they form seed, and by keeping 

 those places constantly cultivated so that the new growth 

 may be killed before it has time to develop. If carried out 

 thoroughly and persistently, this method cannot fail to be 

 successful in the end. If, however, a single crop of the weed 

 is allowed to scatter seed, all the previous work will be lost." 



Further investigation of the life -history of this pest has 

 emphasized the importance of this point. 



390. Early Planting. — Early planting, if sufficiently early, 

 also acts as a check, for in this way the maize plants become 

 well established before the witch-weed has had time to injure 

 them. In the Transvaal Bush-veld the is-ona plant rarely 

 appears above ground until the end of January or the begin- 

 ning of February. Unfortunately, however, this treatment is 

 not always possible as it depends largely on the favourable 

 nature of the season, and it is not recommended as a final 

 remedy. In the Transvaal Bush-veld the rains usually fall 

 too late to make it practicable (ibid.). 



391. Manuring. — Stimulating the rapid growth of the 

 young maize plant with fertilizers has a beneficial effect on the 

 crop; but where the soil is full of is-ona seed it is not likely 

 that there will be a good maize crop in any case, and it will 

 be a waste of money to put manure upon such land. Where 

 is-ona has not, however, taken a strong hold, heavy manuring 

 with good kraal-manure or steamed bone-flour is likely to be 

 beneficial, as it will produce a stronger growth of the maize 

 plants, and may enable them to develop ears while supporting 

 the parasite as well. But this is only a temporary expedient, 

 making final eradication still more difficult and more remote, 

 for it does not prevent the ground becoming more and more 

 foul with the pest, and more and more heavily charged with 

 its seeds (Hid.). 



392. Clear the Land of Is-ona Seed already there. — On 



