202 
KEPOET ON ECONOMIC ENTOMOLOGY 
Native 
cultivation 
Clean 
cultivation 
the natives themselves. These savages, nevertheless, graze large flocks and herds of no 
mean quality. Biting flies and other blood-sucking animals, such as ticks, are to be found 
in abundance, and, as many of them are suspected of carrying the various diseases from 
which the natives and their flocks and herds suffer, much useful work might he done in 
studying the bionomics of these pests. 
Farther north, however, more attention is paid to agriculture proper, and in sjreaking 
of the “ natives ” it is the inhabitants of the Central and Northern Sudan to which allusion 
will be made. 
The methods of cultivation employed by even these natives can hardly be looked upon 
as of a very advanced order, their main idea apparently being to follow in the footsteps of 
their fathers. I have rarely, if ever, noticed any regular sj'stem of rotation of crops, and 
this alone, if carefully carried out, will act as a very considerable check to many insect 
pests. While some insects are practically omnivorous, the majority confine their attentions 
to certain food plants, and if these food plants are lacking, they are compelled to go afield 
in search of them or die of starvation. 
Many natives know well that the caterpillars that tunnel in the stems of their dura or 
devour their forage crops will eventually become moths, hut it does not occur to them that 
these moths will eventually give rise to more caterpillars that will attack their crops in the 
following season. 
I have made it a rule, when recommending remedial measures for insect pests, to 
endeavour to explain, as simply as possible, the life-histories of the latter, hut though the 
native will appear politely interested and amused, he has no serious intention of adopting 
these measures; “for,” he reasons, “there always are worms in the dura stalks, hut we 
generally get some dura, so why worry and take unnecessary trouble ; besides, the worms 
are already in this crop and it is a long time before the next.” 
If they see one of the species of dura hugs swarming on their dura and obviously 
ruining it, they are quite keen to adopt any method of catching them, or driving them 
away. It seems to them, however, to be very unnecessary, when once the crop is harvested, 
to destroy the same Inigs feeding on the wild vegetation adjoining their cultivations in order 
to prevent their recurrence in the ensuing year. 
As is well known to the modern experienced farmer, a very important factor in the 
control of insect pests is clean cultivation. When a crop has l)een harvested, all refuse 
such as the stubble should be collected and burnt. In the case of cotton, where the wood 
is employed as fuel, it should be removed from the fields and put to that use as soon as 
possible. One not infrequently sees stray cotton and other 2 Jlants growing on the banks of 
the canals and gadwals, and it is on volunteer growths such as these that many insects jjass 
the time that elajjses between the harvesting of one crop and the ^slanting of the next. 
On no account should the remnants of a diseased cro^) Ije allowed to lie about longer 
than is absolutely necessary. As an example of the harm which may result from such a 
2 )ractice, the case of the IMelon Fruit Fly — Ihicus sjr. — may he quoted. 
It is no uncommon occurrence for melons to decay instead of rii^ening, and if one of 
these melons is cut open it will usually he found to contain numbers of creamy-white 
maggots — the larvae of a small Ijrown and yellow was 2 )-like tly, the so-called Melon Fruit 
Fly. The custom in vogue is to merely detach these diseased melons from the jjlant and 
throw them to one side. The maggots continue to develoj) until, having attained maturity, 
they leave the melon and pujrate just below the surface of the soil. About ten days later 
the adult flies ajjpear, ready to lay their eggs in any melon or cueumljer that may be growing 
in the vicinity. 
