The Battle Against Bark Beetles in Crater Lake National Park: 1925-34
Events From 1932 to 1934 – The Final Years of the Battle
The letters between Craighead and Keen were numerous during spring 1932. Keen was sending weekly reports on the progress of the work to a worried Craighead. The letters commented on difficulties of doing the treatment in deep snow and burning some trees with oil rather than using the solar method.  Keen was continually optimistic, however, that they were on the verge of making a thorough cleanup of the park infestation that year. A last-minute push by Park Service and Forest Service crews cleaned up the infestation around Mount Scott, but the virulent outbreak in the Sun Pass basin continued and no control work was being carried out there in 1932. Craighead closed the June correspondence  by saying,
I was somewhat surprised at your remarks concerning the Sun Pass infestation. I did not realize that it was so virulent. I too feel that conditions reported within the Park control areas are clearly due to the effects of control. If there was some way to estimate bugs rather than trees the effect of the work already done would be much more pronounced than it is on a tree basis when partially infested trees have to be treated.
On November 12, 1932, Keen sent Craighead a copy of his report on the 1932 activities. In the transmittal letter Keen said, “There was nothing much to report about this situation this year except the good news that the beetles have finally been brought under control, and nothing more is needed except a small yearly maintenance program until stable conditions have been definitely restored.” 
Keen reported 20,311 trees treated at a cost of $17,357. On the old control units, the reduction in infested trees from 1931 to 1932 was 74 percent.  In the report Keen stated, “The goal of the mountain pine beetle control campaign in Crater Lake National Park has finally been reached with the completion of the work of this year. All of the aggressive infestation in and adjacent to the southern half of the Park has been disposed of, and the fall cruises show that there are no longer any active centers in this entire area.” He warned that beetles might still invade the park from the Sun Pass area, but his final recommendation was for the Park Service to treat about 5,000 trees in the old control units and the Forest Service to treat 22,000 trees in the Sun Pass area. He called the Park Service work “maintenance control” and thought it would be necessary for only a few seasons (see footnote 40). A report by Frank Solinsky, in charge of control work for the Park Service, referred to the deep snow pack that persisted well into June, thereby slowing Control work. He also noted a week or more of cold snowy weather in mid-July that slowed the work further. And he commented favorably on the new development of oil burning infested trees in shady areas where the solar method was not effective. He stated that over 100 men were employed in the bug camps that year by the Park Service. 
Craighead closed the year with these comments in a November 29, 1932, letter to Keen: 
Your report of the present status of the Crater Lake control project transmitted with your letter of November 12 is most encouraging. It finally looks as though we have got the upper hand of this job. Indications are that nothing further will be necessary for the next few years except some maintenance work, provided the Sun Pass infestation on the National Forest does not get out of hand. Obviously it is a toss-up whether or not this will spread into the Park. I am afraid that when the infestation reaches a certain degree of intensity it is going to serve as a source of reinfestation of the park land. This danger will necessitate annual surveys of the Park timber for the next few years and some action will have to be recommended if there is an obvious reinfestation of the cleaned area.