REMEDIES AGAINST SCALE-INSECTS. 89 



The feet and tail-feathers of birds are also invaded by the crawling 

 lice, which are thus borne with them in their flights to be scattered over 

 new plantations. 



The leaves and branches of shrubs and trees standing to the windwanl 

 of a grove protect it by receiving these pest-laden visitors, and detain- 

 ing them long enough to relieve them of the scale-larva' they b( ar ujion 

 their bodies. 



It is, therefore, a great protection to leave narrow belts of timber be- 

 tween adjoining groves, allowing the undergrowth to spring up and form 

 a natural screen, or else to replace this with cultivated plants. Fences 

 may usefully be replaced by thorny hedges, which will aid in maintain- 

 ing an etfective quarantine against invasions of Scale-insect and other 

 minute pests. 



To be of value the screen or hedge should, of course, be composed of 

 siich plants as are not themselves subject to the attacks of orange insects; 

 otherwise it may first become infested and afterward prove a source of 

 danger, in place of a safeguard. For example, the Oleander is not desir- 

 able in the neighborhood of orange trees, because of its liability to the 

 attacks of certain soft Scale-insects {Lecanium.) On the other hand, 

 pines, cedars, and other coniferous plants, having very few insect ene- 

 mies in common with other plants, are absolutely safe, and are also 

 admirably adapted to form wind-breaks. 



CLEANLINESS. 



Beneficial action of Light. — It is with plants as with animals, a rule to 

 be borne in mind that foulness breeds vermin. The growing bark as 

 well as the leaves has its pores and its respiratory functions, for the 

 proper performance of which it needs exposure to light and air. From 

 the lack of these conditions for healthful growth, the inside branches 

 of orange trees dwindle and lose vitality, becoming breeders of Scale- 

 insects, which thrive best when the plant has lost its vigor. 



Pruniitff and opening Tops to Light and Air. — Upon trees of consider- 

 able size and which have formed dense heads. Bark-lice usually make a 

 start npon the devitalized inside branches, and from thence they may 

 spread over a portion or the whole of the tops. 



It may be doubted if any bearing orange tree entirely free from scale 

 can be found in Florida. Somewhere under the canopy of leaves there 

 will always be a twig or stifled branch upon which the enemy lurks in 

 concealment, latent, but ever present, and wniting for favorable condi- 

 tions to swarm forth in destructive numbers and possess the tree. The 

 careful cultivator needs not to be warned of this source of danger, and 

 will not allow dead and dying branches to remain and accumulate until 

 they become a menace to the health of the tree and breeders of insect 

 pests. He will frequently examine his bearing trees, and at least once 

 each year remove the unfruitful and devitalized inside growth from their 

 tops. 



