CHAPTER VII. 



MEANS OF DEFENSE AGAINST SCALE-INSECTS REME- 

 DIES. 



INTRODUCTION OF SCALE-INSECTS ON IMPORTED PLANTS. 



In the wide range of insect life few forms possess a greater vitality 

 than is found among the Bark-lice, and none are more readily trans- 

 ported upon plants from place to place, and from one country to an- 

 other. Whenever orange plants are imported from infested districts, 

 Scale-insects will be brought with them, and their introduction and 

 spread in regions where they were before unknown are inevitable. 



Even the soft and unprotected Coccina3 sustain without injury an as- 

 tonishing amount of rough handling, and exist for long periods of time 

 without food or moisture. 



During the winter of 1882->83 living specimens of the Common Mealy- 

 bug (Dactylopius adonidum, Linn.) were sent to the writer, through the 

 mails, from Italy and also from Morocco, inclosed with a few orange 

 leaves in common letter envelopes. Although the orange leaves were 

 entirely dry, and some of the insects were crushed between their sur- 

 faces, many, even of the adults, were found to be uninjured, and young 

 lice had even been produced in transit. 



The scale-covered Diaspina3, it may well be supposed, are even better 

 able to sustain long voyages than their soft-bodied relatives, and their 

 eggs are not affected by long-continued drought, nor by sudden changes 

 of temperature. 



It can hardly be doubted that all the common Bark-lice found upon 

 the Orange in Europe have been many times imported into Florida upon- 

 living plants. In this way, in the year 1835, it is supposed, the com- 

 mon Long Scale (Mytilaspis gloverii] was introduced, first at Jackson- 

 ville, and subsequently at Saint Augustine, from whence it spread de- 

 vastation over all the groves then in the State. 



In 1855, according to Glover, a new scale, probably the Chaff Scale 

 (Parlatoria pergandii), was introduced into Florida on some lemons sent 

 from Bermuda. More recently a new and very destructive scale has 

 made its appearance at Orlando, in Orange County, Florida, and is 

 slowly but surely spreading to other parts of the State. This is the 

 Eed Scale of Florida (Aspidiotus [Ghrysomplialus] ficus Ash mead). It 

 was first observed in a grove near Orlando, in the spring of 1879, upon 

 a sour-orange tree brought from Havana, Cuba, in 1874. Professor 

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