ENCLOSURE TO PART 1V.
Arising out of some remarks by Mr. Ritchie, Mr. Fuller observed
that there seemed to be a distinct danger of the spread of Pink Boll
Worm from ginneries, and suggested that this question should be
further discussed with the Cotton representatives in connection with
item 5 of Catecory 111. of the Agenda.
PREVENTION OF INTRODUCTION OF PESTS AND DISEASES.
The question of the adequacy of present methods of disinfection
as a safeguard against the introduction of pests and diseases was then
discussed.
Mr. HARDENBERG said that, in Portuguese East Africa, they
were not satisfied with the regulations in regard to the importation of
cotton seed as to whether they were entirely effective in preventing
the entry of Pink Boll Worm. Personally, he put no faith in the
heat treatment of cotton seed and based his opinion on his experience
with a parcel of 5lbs. of cotton seed, which was being imported into
Lourenco Marques from Egypt via Liverpool. This seed was said to
have been subjected to the heat treatment before leaving Egypt and
again disinfected before despatch from England. Nevertheless, upon
arrival it was found to contain a very considerable number of live
larvee and pup of the Pink Boll Worm, while between the outer and
inner wrappings several specimens of the adult were found
(subsequently determined by Dr. Janse in Pretoria as Platyedra
gossypiella). He had also tried the treatment of cotton seed by the
sulphuric acid process, and this method appeared to be more
satisfactory than that of fumigation, although he was not satisfied
that it was entirely successful, as in the twin seed stage sulphuric acid
might not penetrate the silky covering.
Mr. KIRKPATRICK said that climatic conditions affect twin
seeding, which is a feature of those countries only that have a
definite cold season.
CONTROL OF BOLL WORMS.
The Section then considered the questions on the value of control
of Boll Worms asked by the Empire Cotton Growing Corporation
(Agenda, Category VII., item 6), and agreed to submit the following
observations in respect of Pink Boll Worm to the Combined Cotton
and Entomological Conference :-Control
 by Natural Enemies. There is no effective control
by natural enemies. In Egypt one of the parasites present,
Pimpla Roborator, does become common at the end of the
season; and it is more than likely than by a thorough
knowledge of its bionomies its numbers could be increased
early in the year, thus checking the rapid increase in the boll
worm population. But it can definitely be stated that,
without a great deal of research, nothing much can be
expected from natural enemies
. and (1) Elimination of Food Plants. While recognising that
further work is essential in the determination of native host
plants, it can be stated that the value of the elimination of
alternative food plants depends gn the life-history of the
boll worm in any given country, which is determined by the
climate. In countries with a definite winter, where cotton
i's a summer crop, the Pink Boll Worm spends the winter

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