9 



The table very clearly shows, firstly, a gradual change as the 

 season progresses from the short-cycle habit to the long-cycle habit, 

 and, secondly, a very rapid increase in the number of long-cycle worms 

 at the end of the season. Thus a hundred average green bolls contain 

 no long-cycle worms at the beginning of August, six at the beginning 

 of September, and 93 at the beginning of October. Similarly a hundred 

 average open bolls contain four long-cycle worms at the end of August, 

 twenty-one at the middle of September, and 166 at the middle of 

 October. From these figures it can easily be realized that the earlier 

 the production of bolls is stopped, i.e. the earlier the cotton sticks 

 are pulled up, the fewer by far will be the number of hibernating 

 boll worms left to carry on the infestation, and that the difference 

 of only a few days at the critical period may make a quite appreciable 

 difference to the attack the following year. 



As already stated the attack of the pink boll worm throughout 

 the country has been on the decrease during the past three years. 

 Table VI gives the percentage of green bolls attacked (observed) and 

 the number of worms per 100 plants (calculated from the last figure) 

 at various dates in the Delta, similar to the figures given for Wadi 

 Tumilat in Tables I and IV. 



TABLE VI. Lower Egypt. 



The decrease in the severity of the attack shown by these figures 

 is really very remarkable, considering that direct control measures 



* These figures are too low owing to the fact that practically nil the samples received during 

 this, the last, week came from the Northern Delta where the attack is always lighter. The other 

 samples were fairly representative of the whole Delta. Accordingly no averages have been 

 calculated for 1918 as they would not be comparable with the other yean. 



