4 BULLETIN" 173, U. S. DEPARTMENT OF AGRICULTURE. 



Also in 1911 Mr. P. J. Parrott 1 published an account of the appear- 

 ance of this species in New York State, and in January, 1912, he 

 issued a more extended account of the pear thrips in New York. 2 



HISTORY IN ORCHARDS AND DISTRIBUTION. 



The first reported injury caused by the pear thrips was noticed in 

 the year 1902, in an orchard owned by Judge S. F. Leib and Mr. G. M. 

 Bowman. This orchard was situated in the Berryessa district of 

 the Santa Clara Valley, near San Jose, and consisted chiefly of the 

 Imperial variety of prunes. The injury was noticed at first on about 

 20 or 30 acres of the 200 acres of orchard, and the cause of the trouble 

 at that time was unknown. In the spring of 1904 every other row 

 of this orchard was top-worked with sugar prunes, chiefly to secure 

 better cross-pollination with the Imperial variety of prunes, the lack 

 of which was supposed to have been the cause of failure of the crops 

 in the past. During a drive through 100 acres of this orchard the 

 fruit buds were observed to be just beginning to show the white tips 

 of the petals, and the prospects seemed excellent for a good crop. 

 When revisiting the place five days later, the owner found to his 

 utter astonishment that the whole orchard had the appearance of 

 having been scorched with fire and that there was not an average of 

 a dozen blossoms to the tree. 



The thrips were discovered this same year (1904) in the orchard 

 of Mr. R. K. Thomas, on Cypress Avenue, near Stevens Creek Road, 

 about 7 miles distant in an air line from the Leib orchard. From 

 these two orchards infestation has, with the exception of a few acres, 

 spread all over the Santa Clara Valley and into other valleys sur- 

 rounding the San Francisco Bay. 



No exact information is available as to the first appearance of the 

 thrips in other counties, but many orchardists claim that it has been 

 in Contra Costa County since 1904 and in Solano County at least 

 since 1906. In addition to these centers of infestation in Santa 

 Clara, Contra Costa, and Solano Counties, the insect is now present 

 in considerable numbers in Alameda, Sacramento, Yolo, Napa, 

 Sonoma, San Joaquin, and San Benito Counties. The general area 

 of infestation in California is indicated in the accompanying map 



There have been several reported outbreaks of this species in other 

 parts of the State, notably from the Sierra Nevada foothills near 

 Newcastle and Auburn, near Red Bluff and Anderson in the Sacra- 

 mento Valley, and from the fruit districts of Tulare and Fresno 

 Counties in the San Joaquin Valley. The species in question, how- 



] Parrott, P. J. Occurrence of Euthrips pyri Daniel in New York State. In Science, n. s., v. 34, no. 864, 

 p. 94, July 21, 1911. 



2 Parrott, P. J. The Pear Thrips. N. Y. Agr. Exp. Sta., Geneva, N. Y., Bui. 343, p. 341-366, 4 figs., 

 pis. 30-33 and 1 col. pi., Jan., 1912. 



