494 rHOC'EEDIXGS OF THE THIRD EXTOIIOLOGICAI. MEETiyu 



provenant de I'Etranger) was passed. It had been asked for before the 

 Pink Bollworm had been recognised to be an imijorted pest, and was 

 intended to act as a safeguard against similar occurrences. The Law 

 proliibited the importation of unginned cotton, cotton-seed, cotton-sticks 

 and hving cotton-plants. It further subjected all living plants introduced 

 into Egypt, apart from a few exceptions, to be fumigated at the 

 port of entry. This law was replaced three years later by a new 

 law {Loi No. 1 de 1916 svr la Protection des Plant es contre les Mahdies 

 provenant de I'Etranger) which prohibits the traffic in ginned cotton as 

 well as cotton-seed and gives improved facilities in a few other weak 

 points which had been found out in the course of time. Our work on 

 the methods of control was begun in 1912 when treatment by fumi- 

 gating seed in sacks was tried. At that time the insect was a very 

 minor pest, and treatment of the seed in bulk could not be thought of 

 on account of the opposition expectable from the ginneries. 



It was then already recognized that treatment of the seed alone 

 would lead nowhere, unless treatment of the rejected bolls in the field 

 was insisted on. 



In 1913 we concluded that whatever steps were taken to free the 

 seed from worms, the seed would have to be treated in bulk. Further, 

 that it would be as absolutely necessary to treat all the seed produced 

 as it was necessary to insist on the destruction of all the bolls left on 

 the trees after the last picking throughout the whole country. In 

 dealing with an insect hke the Pink Bollworm one must insist on the 

 widest and simultaneous apphcation of the measures decided on, if 

 any relief is to be expected. 



The methods tested in 1913 were mechanical and chemical. Of 

 the mechanical methods treatment by hot water, by hot-air, by cold 

 and by vacuum were tested. It was found possible to kill the worms 

 by immersion in hot water, without injuring the germination of the 

 seeds. To quote from a paper by Gough and Storey, " The fatal 

 temperature for Gelechia lari'ce must lie very close to 50° C, as 50° 

 applied for five minutes kills ninety-seven per cent, of the worms. One 

 minute at 54° was not sufficient to kill all the worms, but two minutes 

 at 55° were absolutely fatal to them. Temperatures of 55° and over 

 were invariably fatal." 



The temperature hmits of the seed were also given : — " Immersion 

 in hot water at temperatures of 50° to 55° appears to have no bad 

 influence on the germination. However, five minutes at 55° appear 

 to have stimulated the germination. Stimulation of the germination 

 certainly appears to take place after immersion for one minute at 60°, 

 65°, and 70°, though longer exposures at these temperatures still appear 



