119 



One section of tlie greenhouse was kept dry and cool, while the 

 other was kept as damp and muggy a& possible, for the purpose of 

 determining whether different climatic conditions would in any way 

 affect the burning of the foliage by the Paris green. In watering 

 these trees, three in each section were showered from above so that the 

 foliage was thoroughly wet, while the others were watered at the 

 roots, and the foliage was not wet during the entire time of the 

 experiment. No apparent difference could be observed in the effect 

 on the foliage between those trees which were showered from above 

 and those which were not ; but there was a marked difference be- 

 tween the foliage on the trees in the two sections of the greenhouse. 

 In the section which was kept cool and dry, the foliage was scarcely 

 burned at all, while in the one which was kept damp and warm, it 

 was very badly burned. We conclude, therefore, that Paris green 

 burns the foliage much more in warm, damp weather, than when it 

 is dry and cool; and further, that simple showers do not cause the 

 Paris green to burn the foliage perceptibly. 



PLANT LICE AND RED SPIDERS ON ROSE BUSHES. 



Twelve potted rose bushes of different varieties were placed in the 

 Insectary greenhouse last April ; and, as the}' were infested with 

 plant lice and red spiders, those insects were allowed to multiply till 

 the lice literally covered every green twig, and more or less of the 

 surfaces of the leaves ; and the red spiders had become exceedingly 

 numerous on the leaves. 



A pailful of kerosene emulsion was prepared, and each rose bush 

 was inverted and dipped into it, and held there about a quarter of a 

 minute, or long enough to allow the emulsion to reach every insect 

 on the bush. In immersing it in this way, the pot was held in the 

 left hand, with the right hand over the top to prevent the earth from 

 falling out. An examination of the bushes, two days later, failed to 

 reveal a single plant louse or red spider, and none appeared on them 



