SCALE INSECTS IN GEEENHOUSES 



PROF. W. LOCHHEAD, 



OF THE BIOLOGICAL DEPT. O A. C, GUhLl'H. 



MOST PERSONS who have ever 

 attempted to grow the larger 

 house plants, such as crotons, 

 oleanders, lemons, date palms, ferns and 

 acalyphs, which find their habitat in tropical 

 regions, have no doubt felt frequently ag- 

 grieved on account of the presence of soft 

 insects which do considerable harm. These 

 soft insects are very diverse in character, 

 some of them having a mealy appearance, 

 while others are quite scale-like. The cro- 

 tons and the Oleanders are especially trou- 

 bled with the mealy-bugs, while the lemons 

 and ferns harbor a species of a soft scale 

 called lecanium. 



There are usually two species of the 

 mealy-bugs common in greenhouses, the 

 destructive and the long-threaded. Unlike 

 most scale insects, they can move about the 

 plant somewhat freely. It is only when 

 they become mature that they secrete he 

 cottony sack which is so characteristic of 

 them. Within this cottony sack are de- 



posited the cream-colored eggs, which in a 

 short time hatch out the young mealy-bugs. 

 Fig. 2578 shows clearly the appearance of 

 these two mealy-bugs. With regard to re- 

 medial treatment, probably the best method 

 of dealing with these insects is to wash the 

 plants with a soap solution, or to dip the en- 

 tire plant in the solution, if such is practi- 

 cable. In either case the plant should be 

 drenched with clear cold water to wash off 

 the solution. Another remedy which has 

 been highly commended is an alcoholic ex- 

 tract of Persian insect powder. This Is 

 made as follows : Alcohol, ^2 pint ; insect 

 powder, 2 ounces. These are allowed to 

 stand for about a week, then filtered and di- 

 luted with an equal quantity of water. The 

 solution is then applied with an atomizer. 

 It will be necessary in most cases to repeat 

 the treatment. 



Mealy-bugs require about six weeks to 

 complete their life circle, that is, from the 

 eggs of one generation to the eggs of the 



