416 



Yearbook^ of Agriculture 1949 



mies to our elms, and control of the 

 beetle becomes of first importance. 



SURVEYS TO SECURE DATA on specific 

 pests are always less complex. Where 

 the plant is an annual one, as is the 

 case with many of our agricultural 

 crops, data needed may require fewer 

 observations. Even here there is need 

 for specialized technique and sampling. 



When the many kinds of trees and 

 numerous kinds of pests are involved, 

 however, the problem increases in com- 

 plexity. It is therefore necessary to 

 simplify the task as much as possible. 

 In planning, organizing, and executing 

 procedures we should emphasize the 

 known importance of the pests. Pests 

 of first importance should have first 

 attention. This principle has been the 

 basis of the surveys on native forest 

 pests that have been carried out. It 

 should be followed in the future. 



ESSENTIAL TO ALL FOREST-PEST SUR- 

 VEYS are on-the-ground observations. 

 These provide data on the presence of 

 numbers of the pest and the environ- 

 mental factors that affect its develop- 

 ment. This calls for a system of 

 collecting and recording the observa- 

 tions made by those who frequent the 

 forests and are interested in and con- 

 cerned with their protection. Survey 

 programs are designed to receive and 

 record their observations. Rangers, 

 timber cruisers, and spotters provide 

 useful and important records. The data 

 they supply have been of material help. 

 What they have done, however, has not 

 been as extensive as needed ; for many 

 sections and areas there are few observ- 

 ers, and the means of assembling the 

 records are inadequate. Ways should 

 be devised to encourage and improve 

 such reports. 



To examine each year, even in a 

 casual way, all forest areas for the oc- 

 currence and development of infesta- 

 tions of just the known injurious forest 

 pests is a large order an objective it 

 is scarcely practical to attain now. 

 Fortunately it is not yet necessary to do 

 this to obtain data needed to secure 



reasonable protection of our forests 

 from pests. Many factors influence the 

 behavior and development of the na- 

 tive insects and diseases injurious to 

 our forests. Even the weather plays an 

 important part. Entomologists and 

 pathologists use their knowledge and 

 understanding of these numerous fac- 

 tors in planning surveys. 



THEY CONSIDER also the composi- 

 tion, age, value, and location of the 

 forests. It has been discovered that for 

 at least certain forest types the forest 

 area may be classified into units of de- 

 gree of hazard ; for example, the large 

 area in eastern California and Oregon 

 covered by the predominant yellow 

 pine forest type. Such discoveries and 

 the classification of the forest types in 

 units have made it possible to deter- 

 mine with reasonable accuracy the fre- 

 quency of surveys needed to appraise 

 the status of the principal pests. 



Research in several areas of differ- 

 ent forest types has established that 

 frequent inspections of sample areas 

 provide information on trends of de- 

 velopment of infestations applicable 

 to large areas. Thus an intensive sur- 

 vey of limited sections may suffice for 

 extensive forest areas, except during 

 periods when outbreaks of the pest are 

 beginning to develop. 



DEVELOPMENTS IN AVIATION have 

 supplied a new means for making re- 

 connaissance surveys to secure prelimi- 

 nary data on the occurrence and 

 development of outbreaks of insect 

 pests, and perhaps for a few diseases. 

 Observers familiar with the symptoms 

 caused by injurious insects and diseases 

 can, in a short time and at relatively 

 low cost, secure valuable data on pest 

 conditions that occur over wide areas. 



A few well-timed flights over areas 

 infested and threatened by the recent 

 outbreak of the tussock moth in the 

 Idaho area aided greatly in locating 

 and appraising the extent and intensity 

 of infestation. Extensive, inaccessible 

 areas of lodgepole pine have been 

 quickly examined to locate red tops, 



