Insect Enemies. 95 



can easily be seen with the naked eye, and viewed 

 under a microscope, we cease to wonder at its ravages, 

 when left in undisputed possession for any length of 

 time. See Fig. 23. 



Their depredations will always be found to be on the 

 under side of the leaves, and unless carefully watched 

 for, their presence may not be known until the face of 

 the leaf assumes a spotted ashen hue, caused by their 

 having destroyed the tissue, and in such cases they will 

 be found in considerable quantity and of all sizes. 

 That they should never be alio wed to gain a foothold, is 

 the rule, but in practice it is not always accomplished. 



They thrive and multiply rapidly in a dry, hot atmos- 

 phere, hence, from the time the cutting is made it should 

 be the effort of the grower to prevent this condition. 

 They cannot thrive in a moist atmosphere ; for this rea- 

 son it is desirable to frequently syringe lightly, during 

 dry warm days, wettiiig, at the same time, all wood 

 work of the benches, the walks and ground under- 

 neath, being careful always to give the spray full on the 

 under side of the leaves. To do this effectually, it will 

 be necessary to syringe from different sides alternately, 

 and if the middle bench is wide enough for a narrow 

 walk ill the center, see that a small hose is taken 

 through it occasionally, lest they find lodgment there- 

 You may set him down as a careless workman who 

 lets this enemy gain the ascendancy. If, from any 

 cause, they do become too numerous to conquer in the 



