INSECTS AND VEGETABLE PARASITES INJURIOUS TO CROPS 43 



Dura has also been found to be the victim of numerous other diseases. Fungus 



., 11*11 xl diseases of 



Mr. and Mrs. Broun disco\-ered the larvae of a noctuid moth which bores up the ^u^a 

 stems, and a fungus, Hehninthosporium sorghi which, however, only causes the leaves 

 to wilt. One has met with four forms of Smut, (Ustilaginous fungus), a variety of 

 Puccinia, and what is apparently a baciUary disease — at least a large baciUus was 

 present in a grain head from Sennar, which presented quite a peculiar aspect 

 and showed no sign of insect or fungus infection. Klein, Houston, Potter and 

 others, have drawn attention to the presence and significance of the Schizomycetes 

 in cereals and tubere. 



The proper preventive measures for smut and other fungi have been detailed 

 in several reports. The dura in the Dongola district is said to harbour some kind 

 of Avire-worm or slug, while that in Sennar is stated to be occasionally eaten by a 

 large species of fly.' 



A plant bug or Hemipteron, Aspongopus viduatus (Fabricius), has caused The melon 

 much damage to the melon crop, and specimens of wmged adults and wingless larvaj treatment 

 have been preserved and are figured in this Report. (Plate B, a to d.) 



In this instance the preventive methods are simple and consist merely in 

 shaking the bugs into pans of paraffin or tar early in the year when they first make 

 their appearance. The gravid females that have wintered are thus destroyed, and 

 so the hosts to which they give rise prevented from appearing. Land that has been 

 infected with these bugs should have all the fitter burned in the hibernating season, 

 and an badly infected plants should be pulled up and burned (Theobald).- These 

 precautionary measui'es, it seems to me, nfight very weU be adopted and much loss 

 averted. 



The ' Dura ' Aphis or ' Asal Fly ' 



[Aphis sorghi. nov. sp.) 

 (Plate C.) 



By Fred. V. Theobald, M.A. 



The foUowiug are the structural details of the destructive Dura Aphis Avhich is • 

 causing such havoc in the Sudan. The species is new, and I have named it after 

 the plant it attacks. The details are slioAvn on Plate C. 

 Winged viviparous female. 



Expanse of icings 5*0 to 5"5 mm. 

 Length of body 1"5 to 1*8 mm. 



Head (Fig. 4) broAvn, with a pale green fine behind across its whole length, with 

 three processes projecting forward, one median and one at the base of each antenna ; 

 antenna; brown, the two basal segments green, the third green basaUy, basal segment 



' This probably does not refer to a true fly (Dipteron). P. V. T. 



= Second Report on Economic Zoology, p. 117, 1904. F. V. Theobald. 



