14 BULLETIN 71, HAWAII EXPERIMENT STATION 



KEROSENE EMULSION 



Laundry soap y 2 pound 



Water 1 gallon 



Kerosene (coal oil) 2 gallons 



The soap should be thoroughly dissolved in water while it 

 is boiling over a fire. The solution should be removed to a safe 

 distance from the fire and the kerosene slowly added to it. The 

 mixture should be agitated with a force pump sprayer, using 

 a direct discharge nozzle throwing a one-eighth inch stream. 

 The liquid is pumped back upon itself for 10 to 15 minutes. When 

 completed, the emulsion should have the consistency of cream. 

 The stock solution may be kept for several months and when 

 used should be diluted with 8 to 15 parts of water, according 

 to the nature of the insect to be sprayed. The compressed air 

 knapsack sprayer may be satisfactorily used until the trees are 

 several years old (fig. 2, B, c). 



The Red Scale 



The red or orange scale (Chrysom'phalus aurantii) is circular 

 and flat in form. The female varies from one-sixteenth to one- 

 eighth inch in diameter, and has a transparent scale through 

 which its red body shows. The male is smaller than the female 

 and of gray or dark-brown color. The red scale is not so serious 

 a pest as the purple scale. It appears on the stems, leaves, and 

 fruit. 



Control — The red scale is easily removed by spraying with 

 oil emulsion. 



The Florida Red Scale 



The Florida red scale {Chrysomphalus aonidum), sometimes 

 found on citrus foliage and fruit in Hawaii, is characterized by 

 its circular, flat form, dark-brown color, and medial lighter dot. 

 It has an average diameter of about one-twelfth inch, and ap- 

 pears in great numbers on the underside of the leaves and young 

 branches. When seriously infested with it, the foliage turns 

 yellow and occasionally a tree may die. 



Control — The scale is controlled by spraying with oil emul- 

 sion. 



The Green Coffee Scale 



The green coffee scale (Coccv^s viridis) is soft and shieldlike, 

 and of yellowish-green color with darker markings. It appears 

 sometimes in great numbers on the leaves and stems of citrus 

 trees and covers them with honeydew. A sooty mold some- 

 times develops in the honeydew and gives the trees a black- 

 ened appearance. The green coffee scale also attacks coffee trees 

 in the Kona district, where it is partly held in check by intro- 

 duced parasites and by fungus. 



Control — Spraying with oil emulsion is recommended for con- 

 trol. 



Other Scales 



Other kinds of scale occasionally found on citrus trees include 

 the chaff scale (Parlatoria pergandi; P. ziziphus), the red wax 



