10 



An experiment was carried out at Nag Hamadi last winter on a 

 l;i.rge scale by the Sugar Company in which "sets" treated in emulsions 

 of mazoot and paraffin of varying dilutions and for vary ing times were 

 planted out. The field chosen was planted out at the beginning of 

 October and was land which had borne cane for the previous three 

 years, the last crop having been harvested the previous April. This 

 land was not properly worked over until shortly before planting, 

 thus providing the insects sufficient food to carry on until the new 

 " sets " were planted. When I examined the field early in December 

 75 per cent of the young shoots were infected. In two small plots 

 the " sets " had been dipped in pure paraffin and mazoot respectively, 

 only one per cent of these had germinated ; but even they were found 

 to carry living insects. This is conclusive proof that the insects had 

 reinfected the canes subsequent to planting. It was unfortunate that 

 such a field should have been selected for so elaborate an experiment as 

 any results obtained are not only valueless but actually misleading. 

 I may add that I also found in many cases that the " sets " had not 

 been thoroughly stripped of leaf sheaths, thereby affording the 

 insects shelter during immersion. 



The planting of cane in October is unusual and should be 

 discouraged from the outset. Cane thus planted is cut in January or 

 February year, i.e. after a growing period of sixteen months. This 

 is bad for insect control, affording as it does a longer period for the 

 insect in which to breed and work its ravages. Also it does not 

 appear very economical as the land is occupied for the better part of 

 two years to give only one cutting. The normal time for planting out 

 is from March to May and for cutting from December to March. 



After the land, then, has been under cane for two years (one 

 ratooning) it should be given a rest for at least one year and may 

 during this time be planted out with any other crop at the discretion 

 of the owner, This enables the land to free itself of all infection 

 before the next crop is planted. 



I have not yet found Pseudococcus saccliari CKLL. on any other 

 crop or weeds around the field. Haifa grass, which is prevalent 

 everywhere, does not appear to be infected ; it would be a very serious 

 stumbling block to the control had it proved susceptible. The only 

 other host plant I have yet found is that known as " Heesh ": SacclM- 

 rum biflorum or ocgyptiacum. This plant, which grows along certain 

 canals and on waste spaces, is thought to be the original ancestor of 

 our present cultivated sugar cane, so it is not altogether unexpected 

 that Pseudococcus sacckari CKLL. should bestow its attentions upon it. 

 Fortunately "Heesh" is not frequently found in the neighbourhood of 

 the sugar cane fields and so the attack on this grass need hardly be con- 

 sidered in connection with the control of the outbreak on the sugar cane. 



