132 



KEPORT OF THE EN'TOMOLOGICAIi SECTION 



Black or 



Greasy 



Cutworm 



The basin 

 system of 

 irrigation 



(d) When a young crop of dura, maize, sugar-cane or wheat is about a foot in height, 

 all plants containing caterpillars should be pulled up, and the caterj)illars cut out and 

 squashed. This operation should be carried out again two or three weeks later. 



Plants containing caterpillars can be known by their young centre leaves being withered 

 and dying or dead, while their outer lower leaves are still green and living. 



(e) Stray plants of dura, maize, sugar-cane or wheat should not be allowed to 

 grow among other crops or in odd places such as the edges of gudwals (water channels). 



The Black ob Gbeasy CuTwoiur 

 Agrotis i/psilon, Rott. 



A very considerable amount of damage was suffered by crops on Nuri and Gureir 

 basins in Dongola Province, owing to the ravages of this cutworm, in November and 

 December of 1909. A. ypsilon is a well-known pest in many other countries, including 

 the United States, Ceylon and Egypt, attacking tobacco, tea, cotton, berseem and a 

 host of other plants. 



Life hisfori/ and habits. — The female moth deposits her eggs on the lower parts of 

 the food plants, and, on hatching, the larvaB at first feed freely on the foliage. After a 

 few days spent in this way they acquire the habit of feeding only by night and hiding 

 by day in cracks and holes in the soil. As these older larvae are poor climbers they 

 usually cut off young seedling plants close to the ground to enable them to feed more easily 

 on the tender leaves. They will also sometimes attack the plant below the ground. 

 When mature they are about two inches in length and of a dirty green colour with 

 darker spots or tubercles. If alarmed they at once curl up and feign death. They 

 pupate in cells hollowed out in the soil and after about fourteen days give rise to dull 

 greyish-coloured moths. 



In Dongola Province, up to the present, this pest has confined its attentions to 

 crops grown on land irrigated on the basin system and has not attacked the sakia crops. 

 Sakia land is irrigated by means of waterwheels — sakias — which lift the water from the 

 river or from wells. The basin system of irrigation is briefly as follows. — Where the 

 land levels permit of its being done, canals are dug, along which water flows from the 

 river while it is in flood on to land situated generally behind the river-sakia land. These 

 basins are therefore flooded each year for periods varying with the height to which the 

 river attains, and the crops are sown when the land has become sufficiently dry to enable 

 men to walk about on it. The moths of A. ypnilon lay their eggs on the weeds which 

 spring up as soon as the water has gone and are particularly fond of terroba — probably 

 a GhrozopJwra sp. — a weed which is very plentiful on the basins. The cultural methods 

 practised by the cultivators of these flooded lands are of the simplest. No effort is 

 made to break up or clean the soil prior to sowing the seed by hand in holes made 

 witli a stick — or seluka as it is termed — and as might naturally be expected, the land 

 is very foul. When the crop of wheat, barley, or whatever it happens to be, appears 

 above the ground the land may be lightly hoed to give it a chance of getting ahead of 

 the weeds, and it is then left to itself — unless possibly an effort is made at bird-scaring — 

 until it is ready for harvesting. The cutworms, which are probably already present on 

 the weeds when the seed is put in, attack the crops either from choice, or from necessity 

 if the weeds on which they started life are uprooted just when the crops are available 

 for food. 



In 1909 the crops on Nuri basin were badly attacked, those on Gureir basin to a 

 less extent, while those on the new basin on Kerma plain escaped altogether. This 



