PEOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 703 



large pine bark beetle, witb the evident intention of becoming a jDrimary 

 pest. 



The counter-attacks possible against this mode of invasion are 

 simple. (1) The removal of the bark of trees as soon as they are felled, 

 {2) the burning of the slash and brushwood on the area at the close of 

 the felling opei-ations, and (3) the early destruction of affected trees. 

 The broader strategy is more complex, but is primarily based on the 

 arrangement of felling areas into series, so that the coupe of any one 

 year is not in the neighbourhood of areas under regeneration or near 

 the coupe of the year before. 



In this case the size and location of the felling area as determined 

 by the rules for protection are at variance with those required by the 

 principles of extraction and utihzation. The problem to be solved 

 involves not only the entomologist but also the sylviculturist, engineer 

 and utilization officer. 



I have tried to indicate that we have roughly three classes of control 

 problems: — (1) the control of pests, of intensive cultivation, in which 

 direction Forest Entomology approaches most closely to Agricultural 

 Entomology, (2) the reduction of damage by insects to the standing 

 crop, where the damage is greater than that from other more easily 

 controllable factors, and (3) the prevention of pests which are likely to 

 arise from the new conditions produced by new methods of forest manage- 

 ment, and particularly the creation of uniform forests and pure planta- 

 tions. 



In conclusion, I wish to indicate a few of the difficulties attendant 

 on the investigation of problems of the last two classes. The principal 

 difficulty hes in the scale on which an inquiry has to be carried out, 

 both in area and in time. 



The sample plots that we are using in observing the seasonal history 

 of Hoplocerambyx spinicornis are not small areas ; none is less than 50 

 acres. These areas represent check plots for a block of forest of several 

 square miles, which is kept under continuous detailed observation for 

 at least 5 years. 



In South India, again, we are establishing plots to watch the effect 

 of annual defoliation of teak on the girth increment. The trees will 

 -be felled at the end of a ten-years period and the annual increment of 

 defoliated and immune trees compared. 



In Burma we have observation areas on the ecology of the beehole 

 borer in several forests of the Pegu Yomas and the Upper Irrawaddy 

 valley, that were started four years ago. We have also discovered a 

 method of obtaininir accurate informaticn on the past history of the 



VOL. II * T 



