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JOURNAL OF AGRICULTURE OF P. R. 



or labor, $239.46. This, of course, made such a practice prohibi- 

 tive, even had it been successful in destroying the grubs. 



Flooding as a method of controlling the white grub. 



In localities where there is an abundant supply of water, it was 

 thought possible that by flooding the infested fields for a certain 

 time that the white grubs might l)e destroyed. To test this theorj'" 

 the following experiments Avere made. 



Several lots of white grubs were submerged in a tank of watei- 

 for varying lengths of time. They were then taken out and examined. 



Experiment XXI. — Effect of Flooding on White Grubs. 



In practically all cases the submergence had no other effect than 

 to make the grubs rather sluggish and limp. They soon regained 

 their normal active condition after being exposed to the air. A fur- 

 ther experiment was conducted along these lines to determine whether 

 or not a longer submergence Avould have different results. Several 

 ditches were plugged at each end and filled Avith water. A largo 

 number of white grubs were then placed in the ditches and left for 

 a period of two weeks. The water was then drawn off and the grubs 

 found to be still alive and active. It would seem from the results 

 of these experiments that flooding would ])e useless as a method of 

 controlling the white grubs. 



Use of light to attract beetles. 



Knowing that tlic majority of insects arc attracted to ligltt, at- 

 tempts were made to destroy the beetles by taking advantage of this 

 natural phcnouienon. Ai^c lights and five huiidri'd candle f)()wcr 

 Pitncr gasoline lamps were used in these experiments, and were run 

 througli the beetle season from ^farch to November. The lights were 

 erected over large basins filled with molasses and watei", so that the 

 beetles attracted to the lights woukl fall in and be drowned. In 

 the following experiment two of the lights were erected in the midst 

 of ccinc fields heavily infested with the white grub, while the thiiul 

 was erected on the i-oof of » two-story building in the vicinity. 



