THE ACID LIME FRUIT IN HAWAII. 



11 



and discharging for about 10 minutes. When completed the emul- 

 sion should be creamy white, thicken on cooling, and show no trace 

 of free oil on the surface. When used the stock solution should be 

 diluted with 8 to 10 parts of water. 



Crude oil emulsion. — This emulsion is made in the same way as is 

 kerosene emulsion with the exception that crude oil is substituted 

 for kerosene. Crude oil does not evaporate as readily as do the 

 refined and lighter oils. 



San-U-Zay oil. — San-U-Zay oil and water, in parts 1 and 35, re- 

 spectively, is very effective in controlling aphids and mealybugs. 

 The mixture should be thoroughly agitated by means of a wooden 

 paddle before being applied as a spray. The oil separates when 

 the emulsion is allowed to stand for several days, but the emulsified 

 form is restored by stirring a little salsoda into it. 



ORANGE APHIS (Myzus citricidus). 



The orange aphis or black fly of the orange is one of the most 

 serious of the pests attacking limes. In late winter or spring many 

 little black-winged flies, or green wingless insects, develop on the 

 young tender growth of the tree. They are usually identified by 

 the honey dew which they excrete on the leaves and stems. 



Control. — Tobacco water or nicotine sulphate is commonly used 

 for this sort of pest. A good spray for black flies, mites, and thrips 

 is made as follows : 



Nicotine sulphate 



Laundry soap 



Water 



To be effective the spray must reach every insect. 



The measures suggested for the control of the Florida red scale 

 are also efficient in controlling orange aphids. The kerosene emul- 

 sion should, however, be diluted with from 10 to 15 parts of water 

 before it is sprayed on the foliage infested with lice and aphids. 



COCKROACHES (Eleutheroda dytiscoides) . 



Cockroaches are occasionally reported as girdling and killing 

 3 r oung branches of the lime tree. This species differs from the com- 

 mon cockroach in that the adults are smaller, of a darker brown 

 color, and have smoother wings. They are most commonly found 

 among clusters of leaves or fruits growing in bunches. 



Poisoned bait is recommended for use as a control measure. 



GREEN CATERPILLAR (Plusia chalcites). 



Green caterpillars are the larvae of small moths which lay an 

 abundance of eggs on the foliage of lime trees. The larvse appear in 

 great numbers in spring and grow in a few weeks to 1J inches long. 

 They may be identified by their method of travel, looping along in 

 much the same way as do measuring worms. They are very destruc- 

 tive to the foliage of many kinds of plants, but especially to that of 

 young seedling nursery stock of the lime. 



Control. — As soon as there is any indication of injury from the 

 green caterpillar, an arsenical poison should be sprayed on the plants 

 and trees. A very efficient spray can be made by mixing 1 ounce 



1 ounce. 



3 or 4 ounces. 



4 gallons. 



