36 



frequent sprayings with the kerosene or resin washes. Fumigation is 

 comparatively ineffective against it, because the eggs are not destroyed 

 by this treatment. Spraying is, for the same reaso-.i, effective only 

 when it is repeated sufficiently often to destroy the young as they 



hatch. 



The Mealy Bug. 



The meah^ l>ug {Dactyloj)ius citri K.isso) (tig. 30) of the orange and 



other citrus plants is especially destructive in Florida and the West 



Indies. It is not of much importance in California. 



It occurs very commonly in greenhouses, 

 and has been carried to ever}- quarter of the 

 globe. The insect is mealy white in color, 

 the female attaining a length of nearly a 

 quarter of an inch when fully adult. The 

 edge of the body is surrounded by a large 

 number of short waxy filaments. This insect 

 is active in all stages and the eggs are laid in 

 and protected by a cottony or waxy secretion, 

 the female insect as this is developed being 

 gradually forced from the bark, as in the case 

 of the fluted scale. The adult winged male is 

 light olive brown. 



This species is somewhat gregarious and 

 occurs in masses in the angles of the branches 

 and leaf petioles and about the stem of the 



fruit. The remedies are the emulsions and oily washes, repeated as 



often as necessary to reach the young as the}^ hatch. 



IMPORTANT CITRUS PESTS OTHER THAN SCALE INSECTS. 



THE WHITE FliY. 



The white fl}^ {Aleyrodes citri Riley and Howard) of Florida and the 

 Gulf region (figs. 31 and 32) is not a scale insect, but belongs to a 

 closely allied famil3\ In general appearance and habits, however, at 

 least in its economic features, it exactly duplicates the true scale insects. 

 For many years this very interesting insect has been known to infest 

 the orange trees of Florida and Louisiana and also to be a common 

 pest on the orange in greenhouses. It has been found also on a num- 

 ber of plants other than orange, such as viburnum, cape jasmine, and 

 the aquatic oak of the South. These other food plants are of signifi- 

 cance only in indicating that it may be harbored in situations near 

 orchards in which efforts have been made to exterminate it. The first 

 careful description of this insect and general account of its habits was 

 given by Riley and Howard in 1893, and from their article the data 

 following are largely derived. 



Fig. 30. — Mealy bug {Daclylopius 

 citri) : JIass of insect.s at fork of 

 leaf, showing different stages 

 and cottony excretion cover- 

 ing eggs — enlarged 4 diameters 

 (original). 



