87 



Mealy-bugs require about six weeks to complete their life circle, that 

 is, from the eggs of one generation to the eggs of the next. The soft scales 

 or lecauiiuns, are frequently (luite troublesome to greenhouse and indoor 

 plants. They may be readily recognized by their oval-shaped bodies. ^lost 

 of them are oviparous, that is, egg-layers. The eggs are produced in large 



Fig. 2- 



-A^Soft Scale of Oleander, a, mature female; b, flat male scale; 

 c, arrangement of scales along mid-rib of leaf. 



numbers under the scale. Perhaps the most common lecanium of thfe 

 greenhouse is the oleander scale (Lecanium oleae). Fig. 2 shows the 

 form of the scale and the way the scales are arranged on oleander leaves, 



Lecaniums are also frequently found on indoor ferns, on oranges, on 

 lemon plants, and on acalyphs, which resemble the oleander scale to a 

 great extent, but are referred to different species, such as the hemispher- 

 ical scale and the orange scale. 



The treatment for the soft scales is similar to that used against the 

 mealy-bugs. Small plants are often dipped in soap or tobacco solutions. 

 The most certain remedy is the hydrocyanic acid gas treatment, similar to 

 the method adopted in the nurseries against the San Jose scale. A special 

 compartment is necessary for this work, and special precautions must be 

 taken with regard to quantities used and against possible poisoning. The 

 writer will be pleased to give full directions to anyone who would like to 

 try this method. 



Among the armoured scales which infest greenhouse plants are the 

 Florida red scale (Aspidiotus ficus), and Bouche's scale (Aspidiotus hed- 



