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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



growth. The day was fair but began raining before the various treat- 

 ments were completed. However, the rainfall was slight so it should 

 not have had any effect on the insecticidal qualities of the preparations. 



The treated trees were examined carefully on May 14, 1914. The 

 various treatments had no effect on the growth of the trees, every tree 

 growing vigorously, and there being no difference as far as I could 

 detect between the checks and those under experimentation. In the 

 checks the larvae were actively at work and their abundance was indi- 

 cated by the amount of sawdust exuding from the numerous burrows. 

 All the trees treated with different strengths of scalecide showed 

 just as high a percentage of infestation as the checks. This prepara- 

 tion had no appreciable effect. In the trees treated with carbolineum, 

 either pure or as an emulsion, not a trace of infestation could be found. 

 After searching for several hours one shrivelled and blackened larva 

 was discovered in its burrow. However, I did not wish to injure the 

 trees too much by cutting into all suspicious egg punctures. 



This experiment was again carefully examined on June 18 and con- 

 firmed my previous observations. The checks and those treated with 

 scalecide were nearly all badly infested, many trees with as many as 

 eight to ten borers present, while a few both in the treated and checks 

 were apparently free. Those trees treated with carbolineum and its 

 emulsion were growing even more vigorously than the untreated ones, 

 and not a single trace of the work of the borer in any one of the twelve 

 treated trees could be discovered. These preparations colored the trunks 

 of the trees a beautiful brown, but other than that no injury could be seen. 



Fearing that such a perfect control might be due to other causes than 

 the effect of the treatment, a larger series of experiments was planned 

 for the fall of 1914 and spring of 1915. Discarding the miscible oils, 

 kerosene emulsion was given a trial as it has been recommended for 

 the control of the locust borer (Cyllene rohinio!). In a block of over 

 10,000 trees ready for digging in the fall of 1915, rows were selected at 

 the end which showed the greatest amount of the feeding work of the 

 beetles. On December 4, 1914, groups of twenty trees were each 

 treated with pure kerosene emulsion, carbolineum and carbolineum 

 emulsion. Rows were left between for checks. The material was 

 applied directly to the trunks up to the younger growth. On April 9, 

 1915, twenty-five trees were treated with pure kerosene emulsion, 

 fifty with carbolineum emulsion and twenty-eight with pure carbolin- 

 eum. Just previous to these treatments the trees in the whole block 

 had been pruned carefully. The material was carefully brushed over 

 the trunks, covering all the cut surfaces of the recently removed 

 branches. 



The experiment was examined on June 28. The block as a whole 

 showed a severe infestation, sawdust being present at the base of a 



