EFFECTS PRODUCED BY PINK BOLLWORM ON THE YIELD OF COTTON SEED. 285 



Probably part of this improvement was due to the season having favoured the 

 cotton, and to the crop having been, on an average, two weeks earlier than usual. 

 But there can be little doubt that the effects of the Bollworm Campaign of 1915, 

 and more especially of the very thorough one of 1916, were making themselves 

 evident. Writing in May 1918, it seems probable that no further reduction need 

 be expected this season, as the campaign of 1917 was handicapped by the fuel 

 famine, which hindered the enforcement of the law in respect to the wholesale 

 destruction of insufficiently cleaned cotton-sticks (the fear of which is the only 

 driving force behind the fellahin), and further because the scarcity of shipping 

 has upset the normal outflow from Egypt of the cotton seed, much of which, owing 

 to the congestion caused, has had to stand in the ginneries, unprotected from dissemi- 

 nating the pest at a time when in normal years it would already have been exported. 



The pink bollworm certainly reached Upper Egypt in 1912, and probably already 

 in 1911. The figures given show that the infestation has constantly been much 

 lower than in Lower Egypt. It is not yet evident how far this is due to the special 

 conditions obtaining there, and how far to the first invasion being of more recent 

 date. (It appears to be nearly certain that the first introduction must have taken 

 place near Alexandria.) 



The table further shows that provided it is suitably stored, cotton seed retains 

 its power to germinate unimpared for six years under Egyptian conditions, as all 

 the germination tests for seed from the years 1911 to 1916 inclusive were made in 

 1917 ; the 1917 seed has been germinated in 1918. 



The Nature and Amount of Damage Done by the Pink Bollworm. 



In the following chapters it is intended to show the nature of the damage done 

 by Gelechia, as far as has been ascertained up to the present, and to examine the 

 possibility of estimating its extent. No attempt has been made to show the damage 

 to the quality of the lint or seed ; only the total quantities lost have been traced. 



As will be seen later, calculation of the total quantities of the crop lost annually 

 is possible, and, provided a sufficient number of specimens are taken and care 

 is exercised to avoid errors of sampling, it should further be possible to estimate 

 this loss with a reasonable degree of accuracy. Such calculations are likely to 

 prove useful, both for crop estimation, and in order to ascertain whether the pest 

 is on the increase or decrease, thus affording a means of computing the usefulness 

 or otherwise of the pest campaigns. 



A. The Weight of Sound Seeds from Attacked Bolls. 



It is probably well known that the weight of cotton seed is a very variable 

 factor, and that the same seed weighed on different days gives different values. 

 The fluctuations are without doubt due to the capacity of the seed to take up 

 moisture from the atmosphere and can equal as much as 1 per cent, of the weight 

 in a few days. 



The normal loss of moisture immediately after picking appears to be considerable, 

 as can be seen by comparing the first column of SakeUarides in Table III with the 

 rest of the table ; no such loss was shown in the case of the Ashmuni seed recorded 

 in the same place, which was ginned a considerable time after picking. Seed 



