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A PROPOSED METHOD OF CONTROLLING THE RAVAGES 

 OF LEAF-EATING CATERPILLARS. 



By Gerald C. Dudgeon. 



Director of Agriculture, Egypt. 



The subject which I propose to introduce is one which is of such very great 

 importance in agricultural practice in different parts of the world that I trust 

 it may not be out of place to give a brief account of the experiments in con- 

 nexion with it, which we have been conducting in Egypt and which, although 

 still incomplete, indicate very favourable results. 



There is probably no country in the world more completely dependent for the 

 prosperity of its inhabitants upon the success of its agriculture, than Egypt, nor 

 is it probable that any other region is so generally well provided with the 

 unvarying conditions to which such success is largely due. 



The water supply is not, as in most other countries, dependent upon local 

 climatic conditions, but is everywhere artificially controlled by means of an 

 elaborate and well-organised system of canals, emanating from the Nile itself. 

 In the flood water, which flows in these canals, a large amount of matter is 

 held in suspension, which serves as a rich fertilising agent, annually renovating 

 the soil wherever it is applied. Temperature and humidity exhibit practically 

 no variation which can seriously affect agriculture, and the only uncertain factor 

 which can exert a marked influence upon which results depend is the prevalence 

 or absence of insect pests. 



The isolated position of Egypt with respect to other countries places it in 

 a favourable position to resist the natural introduction of such pests, but 

 where, in spite of this, they obtain a footing, the absence of the natural 

 enemies which control them elsewhere, as well as those nearly invariable 

 climatic conditions, which I have mentioned before, constitute a powerful aid 

 to their establishment and increase. 



In this short paper I propose only to discuss one of the half a dozen 

 important pests which exist in Egypt and to give a short account of the 

 treatment which has recently been adopted to destroy the multitudes of 

 a species of cotton leaf-eating caterpillar which occurs there. 



This treatment promises such a great measure of success that, although it 

 has not yet been adopted upon a very large scale, it is worthy of experiment 

 in all parts of the world where similar pests are found. 



The cotton leaf -eating caterpillar known as the " Cotton Worm " in Egypt 

 is the larva of a Noctuid moth of the sub-family Acronyctinje and is 

 scientifically termed Prodenia litura, F.* Since 1877 this pest has occurred 

 annually more or less numerously upon cotton and other plants, often multi- 

 plying in one of its five annual generations to such an extent as to cause great 

 alarm and even serious damage. In view of the recurring nature of the attacks 

 Government Commissions have been appointed at different times during the 

 past 35 years to study means for their prevention, and in 1905 a regularly 



• Dudgeon, " The Cotton Worm in Egypt," Bull. Imp. Inst., x, 1912. 



