60 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12' 



a circuit as it was possible to cover in a day. The practice of the sur- 

 veyors in getting the records varied according to circumstances. In 

 western Ohio where the jointworm was prevalent and Hessian fly 

 more numerous than in other sections, accurate counts of infestation 

 were made from every field investigated in both seasons. In 1917 

 an indefinite number of straws from each field was taken and the per- 

 centage of infestation calculated. The samples would range from a 

 few less than 100 to considerably more than 100 straws. In the same 

 territory, during the survey of 1918, exactly 100 straws were counted 

 and pulled from each field and one man made the count seated in the 

 back of the machine while another drove from five to ten miles before 

 making another stop. About eighty miles per day were averaged for 

 each county and about ten fields in each were examined. Counts were 

 made for both Hessian fly and jointworm. 



In the northeastern part of the state where there was less of Hessian 

 fly and a difi"erent species of jointworm, Isosoma vaginicolum, a some- 

 what different plan was followed. Here each surveyor was usually 

 working alone and therefore could make no examination while driving 

 from one field to another. Counts for jointworm were made in most 

 of the counties, but this was not so necessary as with Isosoma triticiy 

 because most of the infested straws are discernible from a short dis- 

 tance, and a practiced surveyor can estimate with approximate correct- 

 ness the percentage of infestation within a radius of six or eight feet 

 around the point where he is standing. Also when repeated examina- 

 tions discover only an occasional flaxseed of Hessian fly, which count- 

 ing reduces to less than 3 per cent, the surveyor is apt to feel that he 

 can get a more accurate knowledge of the county he is working by 

 quickening his pace and examining in total a much larger sample than 

 100 straws from each field. He can then visit twenty or more fields 

 in the county during the day, making an approximate estimate of the 

 percentage of infestation and occasionally checking his estimates with 

 an actual count. The chief defect with this method lies in the fact 

 that the indefinite results do not furnish a good basis for comparing 

 conditions from one year to another and the gradual upgrade of an 

 incipient outbreak would be less easy to detect than if there was a 

 definite record of actual counts from every county through a series of 

 years. Whether 100 straws from ten to fifteen fields strung over a 

 county really furnish a substantial foundation for a significant record 

 we cannot yet tell, but Mr. Houser who has worked the western area 

 both seasons and has had extended experience with both Isosoma tritici 

 and Hessian fly thinks the records, meager as they admittedly are, 

 really possess a dependable significance and will become increasingly 

 valuable if the survey is continued through a series of years. Con- 



