EFFECTS PRODUCED BY PINK BOLLWORM ON THE YIELD OF COTTON SEED. 319 



As the treatment of seed intended for exportation abroad to cotton-growing 

 countries where the pink bollworm is not yet established has been mentioned, 

 it is desirable to place on record our opinion of the undesir ability of such a procedure 

 on a large scale. Cotton-seed for exportation to such countries ought to be sent 

 in small quantities only, and consigned in such a way that subsequent re-infestation 

 of the seed is made impossible. For instance, properly fumigated postal samples 

 are probably quite safe. Large quantities if sealed in tin boxes are equally un- 

 objectionable. Samples such as the 2,000 ardebs mentioned above are much too 

 large for safety. In the first place such samples must be treated in a ginnery 

 and the sacks containing the seed will be exposed to all wandering larvae from 

 the time of treatment up to the time of dispatch by rail — a period of several hours 

 or even days. After this the sacks will be transported by railway trucks, which 

 may have recently conveyed untreated cotton-seed or seed-cotton, thus exposing 

 the sacks to further danger. Postal parcels and tin cases are not likely to come 

 into contact with wandering larvae. Mr. Storey's comments on this point are 

 here quoted. 



" In conclusion I should like to make a few remarks on the subject of the treat- 

 ment of so large a consignment of seed for a foreign country. Every effort has 

 been made to ensure that all the worms were killed, but as there were probably 

 not less than 5,000,000 worms in the consignment, and 50 are more than enough 

 to start the infection of a whole country, the survival of 0-001 per cent, must be 

 viewed with alarm if the seed is destined for a country where the pink bollworm 

 does not yet exist. To guarantee that there is not a single worm left alive in . 

 10,000 is humanly impossible. In the first place, whenever the machine is started 

 a certain amount of seed — probably about a kela* — finds its way into the seed- 

 chute before it is properly heated up. Here it remains while the machine is filling 

 up until the seed-chute is opened. In order to avoid this source of danger as far 

 as possible the first two sacks to come through the machine after starting were 

 re-treated, but this does not eliminate the danger entirely. Secondly, after treatment 

 the seed was frequently in comparatively close contact with untreated seed in 

 the store and on the station platform, and a slight reinfection from that source was 

 quite within the bounds of possibility. Thirdly, I found when I got down there 

 that it was proposed to double sack the seed, using new sacks inside and old sacks 

 outside. Old sacks may contain literally hundreds of living worms and pupae. 

 Fortunately it was not too late to eliminate this source of danger by using only 

 new sacks. 



" From this I think it is clear that even in spite of the most careful fumigation 

 the importation of a large consignment of seed, such as the present one, is an 

 extremely dangerous thing." 



Bibliography of Gelechia gossypiella. 



Aders, W. M. (1914). Entomology in Kelation to Agriculture. — Zanzibar Protec- 

 torate Med. and Sanitary Kept, for 1913. 



Andres, A. (1911). Note sur un ravageur de la noix du cotonnier (Gelechia gossy- 

 pielh, Saund.) nouveau pour l'Egypte. — Bull. Soc. Entom. d'Egypte, 1911. 



♦Approximately 20 lb. 



