BUREAU OF ENTOMOLOGY. 399 



studied with the view to their better utilization. Extensive ex- 

 periments on the effect of cold-storage temperatures on the fruit 

 fly in fruits have been undertaken. Information of this character 

 will be useful in connection with questions of exports. 



Fruit flies, Canal Zone. — Investigations at the Canal Zone station 

 have been directed to obtain further information concerning various 

 subtropical insects likely to be introduced into the States. In co- 

 operation with the Federal Horticultural Board, close scrutiny is 

 maintained to insure, if possible, that no foreign insect effects es- 

 tablishment in the zone as a result of the large amount of traffic 

 from all parts of the w^orld which moves through the canal. 



Mango and avocado insects. — Studies of subtropical insects other 

 than citrus insects have been continued at the Miami, Fla., station, 

 special attention being given to the red spider of the avocado, avo- 

 cado white fly, avocado leaf thrips, papaya fruit fly, and others. 

 The red spider has proved to be a pest of major importance in all 

 sections where avocadoes are grown in Florida. The biology of 

 this mite has been carefully studied as a basis for control opera- 

 tions and a preliminary report has been issued. As a treatment for 

 the mite a mixture of sulphur and dehydrated lime has proved to 

 be superior as a dust to pure sulphur, and obviates danger of 

 occasional burning of foliage under high temperature. Studies of 

 the avocado leaf thrips have been comprehensive and a manuscript 

 on the insect is in the course of preparation. This insect can be 

 well controlled by the use of lime-sulphur, nicotine spray, or a 

 nicotine-soap spray. A nicotine dust is also quite efficient in 

 destroying the thrips. The papaya fruit fly continues to be difficult 

 to control in view of its habit of boring into the fruit. By the 

 use of cloth and paper bags applied at the proper time a large per- 

 centage of injury by this insect can be avoided. Several mango 

 insects are also being studied, as the mango shield scale, the blossom 

 Anomala, the tessellated scale, Florida red scale, and the like. 



Camphor scale. — Work on the camphor scale, a recent introduc- 

 tion from Japan, is being vigorously prosecuted in cooperation with 

 the Louisiana State Department of Agriculture, with headquarters 

 at New Orleans. This insect is apparently rapidly increasing in 

 New Orleans, where it was first discovered several years ago. It is 

 also present in the wooded country about 15 miles west and in the 

 swamps just north of the city. Two infestations at Hammond and 

 Baton Rouge, La., previously reported, are believed to have been 

 eradicated. The insect has been found in a small citrus nursery 

 at Lake Charles, La., and steps have been taken to eradicate this 

 infestation if possible. In Alabama the insect appears still to be 

 confined to the general region around Grand Bay and to a single 

 citrus orchard in the vicinity of Mobile. The scale has also been 

 found at Alvin, Tex., on the site of an old nursery, from which 

 it is not improbable the insect has been shipped and become estab- 

 lished at other points in Texas and perhaps other States. The 

 Texas infestation, however, is not especiall}^ intense and the insect 

 apparently is not so successful in maintaining itself in that Stato 

 as in the more humid region around New Orleans. So far as known 

 no additional infestations in Mississippi have been discovered other 

 than those previously reported, namely, at Hattiesburg, Pass 

 Christian, and Biloxi. The infested plants in every instance were 



