1908 ENTOMOLOGICAL SOCIETY. 19 



Formerly the practice was to mark for special winter treatment any trees that were badly 

 attacked in summer, but this was not satisfactory as. such trees frequently became much 

 weakened and sometimes di^d before the winter's frosts closed the scale's season. 



Recognizing the necessity for prompt summer treatment in such cases much pains was 

 taken to procure an effectual remedy suitable for summer use which would destroy the scale 

 without injuriously affecting the trees. In a long series of experiments emulsions made from 

 kerosene and crude petroleum proved the most satisfactory and are really very useful. The 

 varying results so commonly reported from the use of kerosene are largely due to differences 

 in preparing the emulsions and of the condition of the weather when the applications were 

 made. They should be applied only on warm, dry, bright, airy days, and it would appear that 

 the hotter and dryer the weather is the better will be the result in killing the scale and 

 the safer to the trees. Spraying done on trees in leaf is necessarily imperfect for the 

 foliage prevents the spray reaching every part of the wood, particularly the twigs. For spray- 

 ing infested trees in leaf we prefer a rather coarse nozzle which sends its spray through the 

 foliage to the wood much better than a fine nozzle. The oils resist re-attack so well that even 

 if there be considerable breeding after the treatment is given it will not matter, for the 

 majority of the young scales which fix will die and the tree will not be badly affected again 

 during the season. Either kercsene or crude petroleum may be satisfactorily applied wiih a 

 combination pump and diluted with water to almost any per-centage, but to use them with an 

 ordinary pump it is necessary to make an emulsion. Kerosene emulsion 1 in 6 is a suitable 

 strength for hardy foliage and 1 in 7 f"r peach and other tender foliage. That is one gallon of 

 kerosene in a total quantity of seven gallons of emulsion. Crude oil emulsion 1 in 10 is a 

 suitable strength for hardy foliage. This gives one quarter of a pound of soap to the gallon of 

 emulsion and ten per cent, of oil which is all most foliage will resist. Kerosene is preferable 

 for peach trees. I would spray only badly affected trees in summer and follow this with a 

 thorough spraying of the entire orchard with lime and suljjhur in the winter or spring. 



Our experiments clearly demonstrate that lime and sulphur is altogether the most effective 

 remedy we now have. It is also the cheapest and the safest. It is easily applied and we hope 

 by utilizing steam from ordinary threshing engines for cooking to make it more easily procured 

 than any other spray. A larger proportion of lime and sulphur than is necessary in California 

 is recommended for our climate. One pound of lime and one-half pound of sulphur to the 

 gallon of waih giving the best satisfaction in our experiments. We found no advantage from 

 the addition of salt, in fact the best results were obtained where no salt was used, and as it 

 seriously corroded the pump we do not recommend it. 



It will be interesting to this meeting to know how this remedy appears to work out, and 

 as frequent examinitions were carefully made, 1 may speak with considerable confidence. 

 There were so many living, healthy, developing females remaining that in the early examina- 

 tions we pronounced the treatment a failui-e. When ihe breeding season came we were gr. atly 

 surprised at finding no larvfe on treated trees and the little yellow lice simply swarming en 

 trees that were not treated. The microscope showed the mature females on untreated trees 

 to be packed with young, while the large, fresh, oily females on treated trees were enqjty, 

 barren and entirely without any appearance of young about them. The proportion of males 

 in the over-wintered brood U lirgely in excess of the females and this is nature's provision for 

 complete fertilizttion in the spring wh'ch no doubt is indispensable. The males being on the 

 surface and exposed perished from the treatment, and many of the females protected under 

 layers of encrusted scales escaped, but as there was no copulation there was no breeding. 



A m 'st gratifying feature of our w ork is that it shows clearly that the scale may be easily 

 controlled and the vigor of an orchard maintained independent of surroundings. An orchard 

 exposed to reinfestation is of course at a disadvantage, but even this will not prevent holding 

 the scale well in check if regular annual treatments are given. 



