10 BULLETIN 49, HAWAII AGRICULTURAL EXPERIMENT STATION". 



INSECT PESTS AND REMEDIES FOR THEM. 



The lime tree is attacked by several insect pests and fungus dis- 

 eases. In Hawaii it is, however, the least subject to such attacks of all 

 the varieties of citrus. Insect enemies of the lime, with the exception 

 of the Mediterranean fruit fly, may be kept under control by 

 efficient spraying. 



FLORIDA RED SCALE (Chrysomphalus aonidum). 



The Florida red scale is characterized by its perfectly circular 

 form, shining very dark brown or nearly black surface, and medial 

 lighter dot. Its average diameter is about one-twelfth inch and 

 it appears in great numbers on the underside of leaves and young 

 branches of the lime tree. When infested with it the foliage turns 

 yellow and occasionally the tree dies. 



ORANGE SCALE (C. aurantii). 



The orange scale is circular and flat in form. The female varies 

 from one-sixteenth to one-eighth inch in diameter, and has a trans- 

 parent scale through which its red body shows. The male is smaller 

 than the female and of a gray or dark brown color. The orange scale 

 is not as serious a pest on lime as it is on other kinds of citrus trees 

 in Hawaii. 



PURPLE SCALE (Lepidosaphes beckii). 



The purple scale injures young branches, foliage, and fruits of 

 the lime tree. The female is oyster-shaped, often slightly curved, 

 and from one-tenth to one-seventh inch long and about a third 

 as wide. In color it varies from light brown to rich reddish purple. 

 The male scale is very narrow and smaller than the female. 



MEALYBUGS (Ps en do coccus filamentosus and P. cilri). 



Two species of mealybugs (P. filamentosus and P. citri) have been 

 reported as injuring lime trees to some extent in Hawaii. These in- 

 sects usually attack the tree in time of drought, and cause the 

 leaves to assume a malformed appearance. These pests may usually 

 be recognized through the distinctive appearance and the peculiar 

 character of their white waxy excretion. 



CONTROL. 



Kerosene emulsion. — This contact poison is very effective in con- 

 trolling scale insect pests, mealybugs, and aphids, provided it is 

 sprayed with some force upon the trees infested with them. The 

 following is the formula used for making the emulsion: 



Laundry soap i pound. 



Water 1 gallon. 



Kerosene 2 gallons. 



The soap should be thoroughly dissolved in water while it is 

 boiling over a fire. When the soap has dissolved the solution should 

 be removed to a safe distance from the fire and the kerosene slowly 

 added to it. The mixture should then be agitated by charging 



