428 JOURNAL OF ECONOMIC ETNOMOLOGY [Vol. 14 



Species 



Nothing has been said that would indicate what species of thrips is 

 responsible for the injury to peaches that has been described in this 

 paper. At the present time a positive determination has not been made. 

 The species very closely resembles the grain thrips, Euthrips tritici but 

 some thrips experts who have examined material doubt that it is this 

 species. There is a possibility of its being Euthrips helianthi according 

 to Morgan of the U. S. Bureau of Entomology. Paul Jones, Entomolo- 

 gist for Balfour, Guthrie & Company, San Francisco, who has examined 

 material, thinks that the species is Euthrips tritici, although he is not 

 positive that it is. The writer inclines to the belief that Euthrips 

 helianthi is the species which we have been dealing with in our peach 

 orchards. It is a species that is very comm.only found on sunflowers and 

 last fall in fields where there were hundreds of acres of sunflowers in 

 bloom, thrips occurred in large numbers in every blossom. It however, 

 seems to be a general feeder and may be found in the blossom of alfalfa. 

 Burr clover, Melilotus, mustard, and various other flowering plants. 



The great damage which has been done during certain seasons by this 

 species in both the Northern part of the state and the Southern deciduous 

 fruit growing section, makes it a pest of first importance. The injur}' to 

 peaches as it occurred in 1920 in the Ontario section is comparable to 

 that of pears by pear thrips during a season of bad infestation. It is 

 therefore important that some careful work be done on this insect to 

 determine the species, its life habits and methods of control. At the 

 present time we are not justified in stating that the ordinary methods 

 which are used in the control of pear thrips will be a success in the control 

 of peach thrips because the pest is so well protected during the entire 

 time of its feeding on peaches. 



THE RESULTS OF USING CERTAIN OIL SPRAYS FOR THE 



CONTROL OF THE FRUIT TREE LEAF-ROLLER' IN THE 



PAJARO VALLEY, CALIFORNIA 



By Donald D. Penny, Wafsonville, Calif. 



The fruit tree leaf-roller, in the Watsonville^' apple district, continues 

 each season to damage a certain amount of the fruit crop and while the 

 infestation has never becom.e such a serious m.enace as has been reported 

 from some sections of the West, this insect does, however, do enough 

 injury to render it a pest worthy of considerable attention. 



^Ardiips argyrospUa Walker. 



^The city of Watsonville, California, is located on the coast about one hundred miles 

 south of San Francisco, in the center of the Pajaro Valley. This valley contains ap- 

 proximately nineteen thousand acres of bearing apple orchards. 



