INSECTS AFFECTING CITRUS FRUITS 461 



all abundant it is seldom necessary to use any methods of 

 control. 



The Orange Thrips (Eiithrips citri). Within the last few 

 years certain thrips have been doing considerable damage to 

 the oranges in some parts of California. They usually 

 work around the stem or depressions in the skin, making dis- 

 tinct whitish marks which, while not affecting the edible 

 qualities of the fruit, seriously affect its market value, as such 

 fruit cannot be graded as first class. The insects themselves 

 are very minute, and are seldom noticed unless looked for very 

 carefully. Spraying is the most satisfactory means of con- 

 trol. The sulphur-lime spray (see page 415) is the one most 

 commonly used. It is necessary to use great care to reach 

 all parts of the tree, and a high pressure is essential. There 

 are other species of thrips that attack the orange, but their 

 habits are the same and they yield to the same methods of 

 control. 



There are several other orange pests, such as Fuller's rose 

 beetle, Aramigus fulleri, and the diabrotica beetle, Diabrotica 

 soror, which feed on the leaves, doing particular damage to 

 young shoots or to new grafts. The red and silver mites are 

 referred to on page 213. The larvae of certain moths attack 

 the fruit and sometimes the leaves also, but these are usually 

 of little importance. 



The Mexican Orange Maggot (Trypeta ludens). This insect 

 has not yet established itself in the United States. It is, how- 

 ever, a serious pest of oranges in Mexico, and there is always a 

 possibility of its gaining an entrance into this country in spite 

 of the strict quarantine which is established against it. The 

 larvae, or maggots, feed in the pulp of the orange. When 

 fully developed the larvae enter the ground and pupate. The 

 adult fly is yellowish in color, and has transparent wings 

 marked with brownish bands. 



