124 FLORIDA FRUITS ORANGES. 



fruit from the whipping action of southeasterly gales, but 

 afford the best and only hindrance to the spread of mites 

 and bark lice, prohibiting their direct importation upon 

 spiders and other insects through whose aid they are dis- 

 seminated. 



Application of Insecticides. As the rust mite lives ex- 

 posed upon the surface of the plant, neither inhabiting a 

 gall nor making any protective covering for itself or 

 young, it is not a difficult matter to reach it with insecti- 

 cides thoroughly applied. The adult mites are very deli- 

 cate, and readily succumb to applications of moderate 

 strength ; but the eggs possess much greater vitality, and 

 require for their destruction solutions of great penetrating 

 power. The immature mites, while undergoing their trans- 

 formation, are also difficult to kill, and appear to be spe- 

 cially protected by the old skin, within which their changes 

 take place. 



These three stages, the adult, the molting young, and 

 the egg, exist simultaneously at all seasons of the year. 

 The development of the mite has been shown to be very 

 rapid ; the eggs hatch in four or five days, the time ex- 

 tending rarely, in winter, to two weeks. Molting takes 

 place in seven to ten days, and lasts two days. Eggs are 

 probably laid in a few days after the molt. 



In applying remedies it follows from these data that if 

 the mites alone are killed and their eggs left alive, young 

 mites reappear immediately; adults are found in ten or 

 twelve days, and fresh eggs are deposited within two weeks. 

 If the molting mites are also left alive very little good can 

 be accomplished, as a fresh crop of adult mites and eggs 

 will be produced in two or three days. 



In combating the rust mites the difficulty in killing the 

 eggs compels us to adopt one of two alternatives. We 

 must either use powerful insecticides, in solutions even 



