﻿256 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



black smut to grow upon the fruit and thus necessitate washing and over- 

 handhng. 



Spraying should be carried on as for navel trees, but can be continued until 

 the fruit is quite large, if necessary. 



In general it is more difficult to spray an orange tree than a lemon, to 

 do good work, because the foliage on the former is much denser and orange 

 trees are more often allowed to grow down to the ground, thus making it 

 very hard to reach all of the interior of the tree. Then, too, many of the 

 seedlings are very large trees, and require a tremendous dose to cover all 

 of the leaf surface. A lemon tree infested with mealy bug is usually very 

 destitute of foliage and this openness makes spraying an easy matter. 



All trees can be successfully cleaned up if the work done is thorough 

 and persistent. To spray zvhenever the mealy bug is found upon a tree is a 

 very good motto. 



Number of Applications: As every sprayer knows, it is impossible to 

 reach all parts of a tree at a single spraying. In combating so serious a 

 pest as the mealy bug it is therefore necessary to make a number of appli- 

 cations to get results. 



In a badly infested orchard three sprayings should be made within two 

 or three months. The orchard will then be freed from serious smutting and 

 the fruit will be hardly scarred. But the work must not be stopped. The 

 mealy bug is a pest which can hardly be eradicated, for it has too many host 

 plants. Parasites are going to do good work as soon as they get started, but 

 the man who wishes to keep this pest down can do so by first cleaning up the 

 orchard as stated and then spray once or twice a year with the carbolic acid 

 emulsion. The main thing is to keep fighting. That is the only way to get rid 

 of any kind of infection, whether it be weeds, fungous or insect pests. 



Spraying and Parasites: It is not the aim of this office to belittle the 

 work of parasites in any way. We have set aside a large section of badly 

 infested lemon trees for their work alone. Every chance should be given 

 any natural agent which tends to destroy the mealy bug. At the present 

 time the parasites in this section are doing excellent work and it is hoped 

 that their good work shall keep on. 



For checking the spraying work, several rows on the edge of the re- 

 served portion, where there were few parasites, were treated so as to compare 

 them with those left to the parasites. No report can be made on this for 

 several years, in order to give the predaceous friends a fair show. 



The adult ladybird beetle easily escapes the spray. It was noticeable how 

 rapidly they took to wing or fell to the ground and crawled away as soon as 

 the fine spray struck them. But the larvae never escape. In the case of the 

 Cryptolacmus and Scymnus larvae the covering is a dense white, cottony, 

 material like that of the mealy bug, and they are just as susceptible to the 

 spray. Many escaped but the greater number were killed with the mealy bugs. 



The effect of the Carbolic Acid Emulsion upon the Honey-Detv Fungus : 

 It is evident that the thick coating of smut upon the foliage, which grows on 

 the honey-dew, secreted by the mealy bug, is a great detriment to the function 



