35 



neers. The owners had often negflected their trees until it seemed 

 a waste of public funds to attempt to save them when infested by 

 the San Jose scale ; but as the law g-ave me no power to condemn 

 a tree until its value was altog^ether gone, I was oblig-ed to treat 

 such trees whether they were worth the cost of treatment or not. 

 Osage orange hedg-es had become extensively infested by the scale 

 in this district, in one instance at a distance of a quarter of a mile 

 from the nearest orchard. Thickets of escaped fruit trees were 

 g-rowing- beside the roads in fence corners, or by the borders of 

 woods, and these were often more or less infested, and as the 

 country still contained many remnants of its original forest cover- 

 ing there seemed a considerable probability that the scale was ob- 

 scurely distributed far and wide through this forest growth. 



Notwithstanding the discouraging features of the situation 

 we made a serious attempt at fumigation here, which presently 

 look the form, however, of a preliminary operation to show what 

 was practicable by this method in such a place, and what must be 

 otherwise provided for. 



General Restdts. — From our experience at this place it soon 

 became clear that local extermination of the scale was impractica- 

 ble by fumigation, or by a single operation of any kind, unless 

 power were given to destroy utterly everything infested which 

 could not be cleared of the scale at once ; that many of the trees 

 were too large to fumigate, and hence could be treated only with 

 a liquid spray ; that the fumigation process in such a region was 

 slow and extremely costly as compared with any other known ; and 

 that weather conditions often greatly diminished its efficiency by 

 making it practically impossible to hold the gas under the tents at 

 full strength long enough to produce the desired effect. In very 

 windy weather no care in the management could prevent the rapid 

 escape of the gas, as was shown by the strong smell of it on the 

 leeward side of the tent and the absence of any such smell when 

 the tree was uncovered ; and when the weather was very cold the 

 watery vapor from the generators condensed on the canvas and im- 

 mediately froze, lining the tents with ice. In this condition they 

 were likely to break when folded in handling, and the brittle 

 branches of the tree breaking when the heavy tent was hauled 

 across the top, the tents were often torn by the jagged stubs. 



Furthermore, it appeared from subsequent inspections that the 

 cases were few in which all the scales on a tree appeared to be 

 killed, and the frequency with which scales were found alive on the 

 lower part of the trunk, while all were seemingly dead on the re- 

 mainder of the tree, showed that the insecticide gas did not diffuse 



