THE SEQUOIA PITCH MOTH. 11 



ground to cover the pitch exudations. During most seasons the snow 

 eliminates November, December, and January as control months. 



By September 1 all of the eggs which have not been lost have 

 hatched, and the young larvae have attained a size sufficient so that 

 they can be seen and destroyed, and up to June 25 hardly any of the 

 second-year larvae have reached the adult stage. 



The statements under "Habitat" suggest where to look for infested 

 trees. To locate the larvae, separate the pitch exudation from the 

 trees, thereby exposing the larvae. Killing the larvae outright, or 

 taking them up for later counting and destruction, or, in other words, 

 hand picking, is really the only thing that can be done to reduce the 

 numbers of the insect. 



RECOMMENDATIONS. 



If the control work is done without utilization of the pitch, it will 

 be at direct cost ; and the taking up of the larvae, though slower than 

 destruction on finding, is preferable, as it enables a proper checking 

 up of the extent of damage and of the amount of control work ac- 

 complished. But if the pitch is of sufficient commercial value to pay 

 the cost of its collecting and shipment, it would be possible to control 

 the insect by utilizing its products. 1 If the pitch is marketed, it is 

 not necessary to keep a close check on the work beyond keeping tab 

 on the weight of the pitch shipped and the returns from the sales. 



Note. — The statements in this paper, with the exception of those under "Descrip- 

 tion of insect," "Life history," "Relation to the mountain pine beetle," and, to a 

 certain extent, "Remedy," refer to Vespamima sequoia in the Clearwater country of 

 Montana alone and are not applicable in other regions where the destructiveness of 

 the insect is known to assume a different character. 



1 Just before going to press analyses of these resins were received from the IT. S. Bureau of Chemistry, 

 with the following comment. — A. D. Hopkins, in Charge of Forest Insect Investigations. 



" The volatile oils obtained from these two resins are slightly heavier than ordinary oil of turpentine. 

 They show smaller percentages, distilling below 170° C However, as turpentines as heavy as these will 

 find a market as paint and varnish thinners, it is anticipated that no difficulty would be encountered in 

 disposing of the turpentine produced from this material. Especially is this opinion held since * * * it 

 is more than likely that owing to the size of the sample and the manner of packing, as well as the exposure 

 of the crude gum, the percentage of volatile oil is lower than it would be in material which was collected in 

 the ordinary commercial way. 



" The rosins do not appear to differ essentially from the rosin made from longleaf pine, and we have no 

 hesitation in expressing an opinion that it would be entirely suitable for soap-making purposes and would 

 command the ordinary market price according to the grade. Attention may be called to the fact that 

 lighter colored rosins, therefore higher grade rosins, would undoubtedly be made in practice, provided 

 bark, dirt, etc., are kept out of the resin. 



"Nothing was observed in this examination which would warrant the opinion that the nature of the 

 product was due to the particular manner of its production. It is believed that essentially the same product 

 would be obtained by the ordinary commercial chipping of the tree except so far as prolonged exposure on 

 the trunk of the trees, as probably took place with these samples, favors volatilization of the light oils 

 and this affects therelativeproportionsofvolatileoils and ofrosin and'the specific gravity of theoils." — F. P. 

 Veitch, Chief of Leather and Paper Laboratory, Bureau of Chemistry. 



o 



WASHINGTON ; GOVERNMENT PRINTING OFFICE : 1914 



