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that you are familiar with these iasects, having lived iii the Magnolia State, I would 

 consider it a very great favor if you will briefly answer the following questions : 



First. How destructive is the Purple Chaff and Long Scale? That is, what are 

 the general characteristics of an infected tree and its fruit ? How does the tree 

 show being infected ? Some claim here that the leaves curl, turn yellow, and drop 

 off', and that the tender growth dies and the tree presents the appearance of having 

 been scorched by fire. 



Second. What is the best means of exterminating them ? Do you consider dipping 

 and the gas remedy previous to planting absolute proof against scale? Is absolute 

 quarantine the only safe and sure means of freeing the country from this new and 

 now threatening invasion of insect pests ? 



Third. The statement is often made here that the Florida Scales will not live in 

 this dry climate. San Bernardino lays particular stress upon this point. Live scales 

 (Purple and Chaff) have been found on trees planted a year at Pomona, and it wonld 

 seem that if they thrived there the chances of their living and breeding at Riverside 

 and San Bernardino are rather good. 



In your opinion will they not live and thrive in any portion of California where the 

 citrus fruits flourish ? If not, what localities are peculiarly adapted to their well- 

 being ? 



Fourth. How rapidly do they spread, and when is their breeding season. 



Any other information that you can furnish touching this subject will be appre- 

 ciated. The growers here are becoming seriously alarmed. — [Henry W. Kruckeberg, 

 Los Angeles, California, April 21, 1890, to Mr. Albert Koebele. 



Reply. — Mr. Albert Koebele has referred to me your letter of the 2l8t ultimo, to- 

 gether with the specimens which you sent him. The insect which you forwarded 

 and which has been imported into your State upon trees from Florida is the common 

 Purple Scale {Mytilaspis citricola). This is one of the worst of the Florida scales, 

 although not equaling in severity of its attack the San Jos6 Scale, the White Scale, 

 or the Red Scale of California. Its effects in extreme cases are like what you de- 

 scribe. The question as to the possible spread of this insect in California is one 

 which is difficult to decide without absolute experimentation. I am familiar with 

 the idea that has been frequently expressed that these scale insects die out after the 

 first year in California, but should be inclined to doubt it were it not for the fact 

 that while this insect must have been frequently imported it has never taken hold. 

 It is kept in subjection in Florida by horticulturists by the kerosene emulsion made 

 according to the Hubbard formula, a copy of which is inclosed on a separate sheet. 

 The young lice begin to hatch in March. 



There is another brood in July and a third in September or October, and it is at 

 the time of the hatching of the eggs and the migration of the young that the emul- 

 sion is applied with the best results. Some modification of the life-history of the 

 species is to be expected if it establishes itself in California. The rapidity of the 

 spread of this and allied species can be gauged by that of any scale-insect. Unless 

 assisted artificially it is slow on account of the fact that the female is wingless. 



I think there is no cause for serious alarm, for these scales are handled with com- 

 parative ease, and the fact that they have not already established themselves in Cal- 

 ifornia is somewhat of an argument against their accidental colonization in that 

 State.— [May 6, 1890.] 



Another letter. — I spent a day and a half at Riverside, and was shown around 

 by Dr. Claflin, the horticultural commissioner for that district, but I found no Florida 

 scales, except on some orange trees planted out the present season. They have the 

 most thorough system of inspection and of disinfection of any I ever saw. Dr. Claflin 

 informed me that they employ eight inspectors at a salary of $S per day. During the 

 past two years every plant, shrub, and tree growing in the Riverside district has been 

 carefully inspected, and whenever a scale of any kind was found prompt measures were 

 at once taken to destroy it. When only a few scales were found on a tree the twigs 



