PEKSIDIONTFAL ADDEKSS SKCTIOX II. 71 



Aiinval Loss Due to Certain Maize Fests. — Of the insects 

 tluit attack growiiii>- maize in South Africa, the stalk borer, 

 the cut worms (nea? rehitives of the preceding-), the ear worm 

 {Chloridea ohsoleta), the black beetle {Heteroiiijchus arator), 

 and the snout beetle [Strophosonins amplicolUs Fhr.), are the 

 ones of outstanding- importance from year to year. It is 

 impossible to g-ive an exact statement of the actual loss caused 

 by these insects because of the difficulty in getting- accurate 

 statistical records, but all available information warrants my 

 estimating- that there is a total annual loss of at least 25 per 

 cent, for the few pests mentioned.* The average annual 

 3"ield of over nine million muids is tlierefore only 75 per cent, 

 of what it would be if it were not for the insects. Hence the 

 total loss may be calculated as 3,000,000 muids, which, at 

 9s., amounts to £1,350,000, of which stalk borer alone is 

 responsible for 1,200,000 muids, valued at £'540,000. _ At this 

 rate, if insect injur j- to maize could be eliminated, it would, 

 in two years' time, reimburse the country- for the cost of the 

 proposed elevators for handling- the grain crops of the Fnion. 



The loss, though great in the aggregate, is distributed 

 more or less evenly over the farms in the maize-growing 

 districts, and hence the nation little realises the extent of the 

 burden. The loss is virtually an indirect tax levied on tlie 

 public through the farmers. The farmers would certainly be 

 up in arms if the Government proposed to raise such an amount 

 by special tax on the land employed in the production of 

 maize, and yet the stalk borer and a few other insects inflict 

 the burden annually while many farmers remain indifferent to 

 the situation. Under the circumstances, it is highly 

 important to inquire what can be done to prevent so great 

 an annual loss. The only sound proposition is to urge the 

 endowment of research and demonstration work on the full 

 economic possibilities of the crop as a whole, so that all factors 

 entering into the production of tlie crop can be elucidated and 

 the information brought home to those who are in position to 

 make use of it. 



Wheat Inserts. 



On account of its intimate relationship to human welfare, 

 wheat occupies a unique position in the list of cultivated plants. 

 Anything that touches wheat is at once a factor of world-wide 

 importance. All over the world some of the most difficult insect 

 problems centre around this important crop. In South Africa 

 the wheat louse {Toxoptera gramininn) undoubtedly deserves 

 first place from the practical standpoint. In the coastal belt 

 of the Eastern Province a black sheep amongst the ladybirds 

 (Coccinellidsp), EpiJaclma siniilis, is a serious pest at times. 



In the Western Province, Hemiptera, especially Blissus 

 cliplopterus Dist., often do far more damage than is frequently 

 supposed. In all cases a solutir)n depends on thorough research 

 work. 



* For detailed information, see Official Report on the. Maize Stalk 

 Borer (1920), by C. W. Mally, Senior Entomologist, Union Department 

 of Ao;riculture. 



