122 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



there were, however, not nearly so many as in the previous February ; 

 roughly estimated, I should think about one-third the number. In 

 many of these buds 12 to 20 adult mites were present, many imma- 

 ture specimens, and a few eggs. The result of an examination of 86 

 suspected buds gave an average of 1 adults, 9 immature mites, and 3 

 eggs per bud. 



SUMMARY AND CONCLUSION. 



After the experiments which have been made I feel convinced that 

 the application of lime and sulphur will keep this mite in check, and, 

 if the dusting and spraying is continued, will eventually entirely 

 eradicate the pest. 



Various statements have appeared in a section of the horticultural 

 and agricultural press, stating that there is no likelihood of a cure, 

 or even of means whereby the mite can be kept in check; and, fur- 

 ther, that its life history is A^ery imperfectly understood. I would 

 warn all fruit growers against such misleading statements. The life 

 history is now practically fully known, and the experiments which I 

 have conducted and which have now extended over eight years have 

 yielded results, checked by many large fruit growers, which clearly 

 point to the fact that the application of lime and sulphur offers an 

 effective remedy. 



It is interesting to note in this particular that the destructive rust 

 mite of the orange and lemon has been combated in a similar manner. 

 In 1889, according to Mr. Marlatt," large quantities of citrus trees 

 were obtained from Florida, and a species of Eriophyes (E. oleivorus 

 Ashmead) was undoubtedly introduced in the Rivera and San Diego 

 Bay districts of California, where it did considerable harm in the 

 orange and lemon groves. Mr. Marlatt states that " an estimate 

 made from actual count, indicates that the mites and the eggs on a 

 single leaf in midwinter may reach the enormous number of 75,000," 

 indicating some billions of mites for each tree in the active breeding 

 season. He further states that it " is readily destroyed by various 

 insecticides. The eggs, however, are much more difficult to kill, and 

 practically no wash can be relied upon to reach and destroy all the 

 eggs of this mite. * * * The sovereign remedy for the rust mite 

 is sulphur. * * * The advantage of the sulphur treatment 

 arises from the fact that the sulphur adheres to the leaves and the 

 young mites are killed as soon as they come in contact with it." 



A further example of treating another species of the same genus of 

 mites is offered in the case of the cotton-leaf blister mite (E. gossypii 

 Banks.), which made its appearance in the West Indian cotton fields 

 in 1903 b and spread quickly throughout the islands. Here the lime- 



«U. S. Dept. Agric, Farmers' Bui. No. 172. 1008. pp. 38-41. 

 & West Indian Bui., 1903, Vol. IV. pp. 282 and 336. 



