THE MONTHLY BULLETIN. 321 



Preventive Entomology. — An editorial in the last (April) number 

 of the Joitrnal uf Ecunomic Entomology is suggestive of a line of ento- 

 mological work which has been but little developed, but which has great 

 possibilities, especially in a state like California, where the insect prob- 

 lem is vital. In medicine the old sajdng "An ounce of prevention is 

 worth a pound of cure." has been found to be especially true, and we 

 are now witnessing in that science a marked growth in the prophylactic 

 branch as opposed to the therapeutic. In the future, undoubtedly, 

 there will be a great deal of attention paid to what might be termed 

 "preventive entomology." It is true, as the editorial says, that the 

 forecasting of insect outbreaks has its perils, but there are some in- 

 stances where the chances of making a wrong prediction are so small 

 as to be almost negligible. Instances of this kind occur, of course, in 

 comieetion with those pests, such as most scale insects, which have a 

 comparativel}' simple life history and whose ecological relations are not 

 exceedingly complex. A good example of this kind in California is the 

 European Fruit Lecanium, Lecanimn corni. Every spring, in May or 

 June, numerous complaints are received from growers whose orchards 

 are severely infested with this scale. By the time the complaints are 

 received it is too late to adopt control measures. The damage is already 

 done. Yet the insect is not difficult to control and had the grower 

 been informed by some one competent to make a careful examination 

 of his orchard during the latter part of winter when the scale was 

 small, that the prospects were good for a heavy infestation, a serious 

 monetary loss could have been avoided. California, with her large 

 corps of horticultural commissioners and inspectors in every part of 

 the State, is well equipped for this type of work and as a matter of 

 fact it is already carried on to a large extent, but generally at the sug- 

 gestion of the indi^ddual orchardist. Would it not be desirable for the 

 county commissioner, through his inspectors, to examine every prune 

 and apricot orchard in his county during the winter, making careful 

 counts of the brown apricot scale, from which examination he could 

 give accurate information as to which orchard would be badly infested 

 and which would not? With the police power which is granted the 

 county commissioners this policy would have a salubrious etfect upon 

 the quality and quantity of the fruit crop of the county as a whole. 

 There are many other pests which might be handled in this way to the 

 great advantage of the county and especially of those growers who are 

 not sufficiently well informed on entomological questions to make the 

 forecast themselves. The peach worm, Anarsia Uneatella, is an 

 example, the mites or red spiders, another. It might even be possible 

 for a careful observer to predict, by ascertaining the number of eggs 

 on the twigs during winter, whether or not the green apple aphis would 

 be abundant during the following season. It is a fact that only a small 

 percentage of these eggs survive the winter, and it would of course be 

 necessary to take this winter mortality into account in making an esti- 

 mate. Perhaps the mortality occurs sufficiently early in the winter 

 that the examination could be postponed until this mortality had 

 occurred, and still be in time to adopt remedial measures before the 

 leaves come out in the spring. This "advance information," as Doctor 

 Felt calls it, would also save a considerable sum of money for that 

 rapidly decreasing class of growers who spray just "because the trees 

 seem to need it," and for that reason spray sometimes when it is not 

 necessary. 



