73 



scientific cotton research board now being formed by the Government, 

 to consist of Government officials of scientific standing with one or 

 more representatives from outside. Its duties will be to promote 

 research on all problems affecting cotton in Egypt, and without doubt 

 that of the pink boll worm will be one of the most serious. 



Tables are appended showing the quantities of Indian cotton 

 imported into Egypt from 1903 to 1913, the distribution of pink boU- 

 worm attack in buds, flowers and green bolls, the dates of emergence 

 of adults from pods and seeds of Hibiscus esculentus, the results of 

 examination of pods of H. esculentus and 77. cannabinus, the influence 

 of position in which material containing pink bollworms is kept, the 

 emergences of long-cycle moths, the results of light-trap experiments, 

 and the infestation of green cotton bolls by the larvae, and comparing 

 sound and attacked samples and the variations of the percentages 

 of lint in various types of cotton in difterent years. 



WiLLCocKs (F. C). Experiments in Egypt on the Survival of the Pink 

 Bollworms (Resting Stage Larvae) in ripe damaged Cotton Bolls 

 buried at different Depths. — Rept. Proc. 3rd Entom. Meeting, 

 Piisa, February 1919, Calcutta, ii, 1920, pp. 532-547. 



Experiments with light-traps for catching adults of Platyedra 

 {Gelechia) gossypiella are described, and the results shown in a series 

 of tables. By means of 18 light-traps, used on two different plots, a 

 total of 18,953 moths were caught in a little over 3 months. Of these, 

 10,141 were females, 5,959 males, and 2,853 remained unexamined. 

 A large number of the females seemed to have been caught before 

 oviposition commenced. Although females as a rule preponderated 

 in the traps, at times the reverse was the case, and the reason for this 

 fluctuation is not known. These results are not considered encouraging. 

 As regards colour, the indications are that blue and white lights are 

 the most attractive, green next, and red and orange least so. It is the 

 author's opinion that the moths do not travel far to light, but only 

 approach it when brought under its influence during their natural 

 flight. 



Many tests have also been made regarding the survival of resting 

 pink bollworms in fallen bolls buried by ploughing the land for the 

 crop following cotton. The results of these tests are tabulated. Their 

 main object was to obtain confirmation of the survival of pink boll- 

 worms in bolls buried to a depth of 2 to 4 inches, after the removal of 

 the restrictions on the irrigation of land that has grown bersim 

 \Trifoliiini alexandrinum], beans, wheat or barley and has been left 

 fallow after the cotton crop. This evidence was obtained, as there were 

 living bollworms present at that depth at the end of July. It is con- 

 sidered that these infested, buried bolls constitute a source from which 

 the growing cotton crop might be infested ; given only a small per- 

 centage of survivals to the end of June, when conditions are ver^' 

 favourable, multiplication in the cotton fields would be rapid. The 

 survival of buried bollworms was found to be greatest under wheat 

 and bare fallow, and least under bersim. The influence of moisture 

 on the activity of bollworms is probably great, high temperatures in 

 particular inducing the larvae to leave the bolls or seeds and pupate. 

 The small number of larvae in bolls buried at a depth of from 6 to 8 

 inches is probably accounted for by the much moister conditions, 

 causing the larvae to leave these bolls more readily than those under 

 the drier surroundings prevailing at depths of 2 to 4 inches. 



(7734— a) g 



