CITRUS CULTURE IN HAWAII 



13 



insect enemies (1). This work has been attended by success, as 

 is shown by Willard (30, p. 11) . Large quantities of citrus fruits 

 are now produced in the Hawaiian Islands without infestation, 

 but much fruit drops before it fully ripens as the result of 

 punctures by the fruit fly. 



Many growers have successfully ripened citrus fruit with- 

 out infestation by bagging it. In a study of the best methods 

 of protecting the fruit, the station used medium-weight brown- 

 paper bags, and medium-weight cellophane bags to cover grape- 

 fruit, oranges, mandarins, and limes. Four-pound bags were 

 used for grapefruit, three-pound bags for oranges, and two- 

 pound bags for mandarins and for limes. The bags were put on 

 when the fruit was still green and nearly full grown. The bag 

 was placed about the fruit and tied tightly enough to prevent 

 the entry of water in case of rain. A workman can place 50 to 

 150 bags per hour, depending on the convenience of reaching the 

 fruit. No foliage should be bagged with the fruit. Although 

 much rain fell during November and December, 1931, most of 

 the bags were in good condition for from 30 to 50 days, when the 

 fruit was picked. When the fruit ripened — those in the cello- 

 phane bags had deeper yellow coloring and possibly better 

 flavor than the fruits in the paper bags. 



Tree Cockroaches 



Tree cockroaches (Eleutheroda dytiscoides) frequently gir- 

 dle the bark of the twigs and eventually kill the trees. They 

 are commonly found among dense clusters of foliage or fruits 

 growing in bunches. This species differs from the common 

 cockroach, the adults being smaller, of a darker brown color, 

 with smoother wings. 



Control — Tin cans containing a poisoned bait with openings 

 only large enough to admit the pest should be tied among the 

 twigs. 



The Purple Scale 



The purple scale (Lepidosaphes beckii) is a common insect 

 enemy of the citrus species in Hawaii. It appears in great num- 

 bers on the bark, the leaves, and the fruit of the trees and pro- 

 duces honeydew which covers all parts of the plant. The honey- 

 dew forms a favorable medium for the growth of the injurious 

 sooty mold (Capnodium citri) . The adult female is purple col- 

 ored, oyster-shaped, and about three-sixteenths inch long and 

 one-sixteenth inch wide. The male is much smaller than the 

 female and of yellowish color. 



Control — This scale and the sooty mold may be controlled by 

 sprayings with oil emulsion. Good spraying oil can be purchased 

 in most markets, and, when emulsified with water, is ready for 

 use. It is as effective as kerosene emulsion and can be more 

 easily kept in stock. Directions for its use are furnished by the 

 dealer. Kerosene emulsion is used by some growers. The best 

 kerosene emulsion is prepared according to the following for- 

 mula: 



