4 FARMERS' BULLETIN 933. 



now infests nearly all the groves of Florida, and the purple scale 

 is found in greater or less numbers on every citrus tree. 



LOSSES RESULTING FROM INSECT ATTACK. 



The presence of pests on citrus fruit usually causes blemishes that 

 place such fruit in a lower grade. It is generally considered that 

 fruit which has been attacked by the rust mite is also one size, or 

 12} per cent, smaller than it would otherwise be. Fruit without blem- 

 ishes caused by pests prob- 

 ably will reach the market 

 with less decay. 



The better grades of fruit 

 a re more marketable. High- 

 grade fruit finds an early 

 and ready market. Fruit 

 badly attacked by insects 

 and mites is usually sold 

 late in the season, after sus- 

 taining large losses from 

 dropping and incurring the 

 liability of damage from 

 frosts. 



The work of the pests 

 devitalizes the trees. Much 

 of the bearing wood on the 

 inside of the tree is killed, 

 thus reducing the yield. It 

 requires much additional 

 fertilizer to produce a crop 

 of fruit when pests are 

 present. 



METHODS OF CONTROL- 

 LING CITRUS PESTS IN 

 FLORIDA. 



FIG. 1. Adults of the citrus white fly crowding Florida orowers have at- 



the under surface of new orange leaves. Adults , ., 



appear slightly less than normal size. (Morrill tempted to control CltrUS 



and Back.) pests by three methods: 



(1) Fumigation, (2) spraying, and (3) encouragement of bene- 

 ficial fungi. 



FUMIGATION AND SPRAYING. 



Of the two artificial methods of control, spraying and fumigation, 

 spraying is superior under Florida conditions at present. Fumiga- 



