62 



FUMIGATION FOR THE CITEUS WHITE FLY. 



that the owners' fruit-shipping records show annual losses from this 

 source amounting to between 15 and 20 cents per tree. Live scales 

 in all stages, particularly the egg and adult, were very abundant 

 before fumigating, but uj) to the 1st of June careful examinations of 

 thousands of leaves, twigs, and green fruits by Mr. Yothers anil the 

 writer have not led to the finding of a single living specimen of this 

 species in the section of the grove which was the most heavily 

 infested. At tliis season of the year there is usually no difficulty in 

 finding more or less abundant specimens of the spring brood of this 

 insect even where it was so scarce the pre^aous season as to occasion 

 no appreciable damage to the crop. 



COST OF FUMIGATION COMPARED WITH SPRAYING. 



In Florida the average cost of spraying is between 2h and 3 cents 

 per gallon of spray applied. Wlien spraying is done with such effi- 



FiG. U .—Purple scale (Lepidosaphes beckii) , showing different stages of female : a, Newly hatched larva; 

 b, same with first waxy secretion; c to/, different stages of growth; g, mature scale; h, same mverted, 

 showing eggs; / and;, half-grown and full-grown female insects removed from scale. All much enlarged 

 (after Marlatt) . 



ciency that blackening of the foliage and fruit by the sooty mold is pre- 

 vented, at least three applications per year, and usually four or more, 

 are necessary. The mechanical difficulties of spraying with as much 

 effectiveness as tliis are so great as to make the results with ordinary 

 practices far inferior to those from fumigating. In fact the results 

 with sprays have with few exceptions been unsatisfactory in con- 

 trolling the wliite fly or preventing the blackening of the fruit and 

 foliage. In many cases this is largely a result of the character of the 

 labor which it is necessary to employ for such work. For the pur- 

 poses of comparing spraying with fumigating in regard to cost, it may 

 be considered that three appHcations of sprays per year will control 

 the white fly in a satisfactory manner, although in actual practice 

 this is rarely accompHshed unless drought or fungous diseases offer 

 material aid 



