52 DECIDUOUS FKUIT INSECTS AND INSECTICIDES. 



Tulare and Fresno fruit districts, but it was found after a careful 

 investigation that none of these fruit areas was infested. In the one 

 case, at Newcastle, the injury was evidently that of the blossom pear- 

 blight and not a single pear thrips could be found in the whole region 

 at a time when the insects should have been in evidence in greatest 

 numbers. A few thrips of another species (Euth-rips occidentalis 

 Pergande) were found in pear and cherry blossoms in this locality, but 

 this insect is not injurious to fruits, and its presence in blossoms is of 

 no consequence. Thrips from pear blossoms at Visalia were found to 

 be of the species Euthrips tritici Fitch, which also is not usually injuri- 

 ous to fruit trees. The present infestation, then, is confined to the 

 region around and closely adjoining the San Francisco Bay. It 

 extends south through the Santa Clara Valley and into Hollister, San 

 Benito County, north through Alameda, Contra Costa, Solano, and 

 Yolo counties, and also occurs in some rather small areas along the 

 Sacramento River. The area of deciduous fruits, about 60,000 acres, 

 in the Santa Clara Valley, is practically all more or less infested by the 

 thrips; and the other infested orchard sections, such as Hollister, 

 Walnut Creek, and Concord, in Contra Costa County, and Suisun and 

 Vaca orchards and others along the Sacramento River, also include 

 many hundreds of acres. 



The original home of this species is still in doubt. Several men 

 have expressed the opinion that it is of European origin, but, accord- 

 ing to Doctor BufTa, the insect does not occur in Europe, and after 

 examining the species he believes it to be of eastern origin, suggesting 

 China as possibly its original home. 



The various thrips which are seen in roses and in other flowers, and 

 which can be found at almost any time of the year, should not be 

 mistaken for the pear thrips, which is distinctly a fruit-tree pest and 

 does not attack grass, weeds, or cultivated flowers. It has, once or 

 twice, been collected from leaf clusters of rose bushes, but this is not 

 common. The name "pear thrips " was given because the insect was 

 first foimd in pear blossoms, but this does not indicate that it attacks 

 pear trees only. The injury on primes and other fruit trees is equally 

 as serious as that on pears. Thrips should not be confounded with the 

 vine hopper TypJilocyoa comes Say, an insect which is wrongly called 

 " thrips, " but is not a thrips at all. The term " thrip," so commonly 

 used, is also erroneous, as the word "thrips" is both singular and 

 plural. 



CHARACTER OF INJURY. 

 FEEDING IX JURY BY ADULTS. 



Adult thrips appear on trees during late February and early 

 March, when the buds are just beginning to open (PL IV). They 

 remain on the tree until late in April and are thus feeding all through 



