46 CIRCULAR 270, U.S. DEPARTMENT OF AGRICULTURE 



CONTROL 



Since no stage of the common red spider is on the trees during the 

 winter, dormant-season sprays are of no value in its control. In the 

 coastal valleys, where control of the brown rot is often necessary, the 

 sulphur sprays used for this purpose should also be adequate for 

 keeping the mites in check. Otherwise it is better to delay the spray- 

 ing until after the fruit has been picked and then to spray the trees 

 very thoroughly with 1 % gallons of oil emulsion, or with 2 gallons of 

 lime-sulphur solution, or 3 to 5 pounds of wettable sulphur, to 100 gal- 

 lons of water. 



CHERRY FRUIT FLY 



The maggots of the cherry fruit fly (Rhagoletis cingulata Loew) are 

 very injurious to cherries in western Oregon and Washington. They 

 have also been found in parts of Idaho and eastern Oregon but have 

 not become numerous in these localities. The injury is especially 

 severe in years when the cherry crop matures late, since a late season 

 apparently delays the fruit more than it delays the flies, and gives 

 them the opportunity to infest the main crop of cherries. In normal 

 years the maggots live chiefly in seedlings and late 

 varieties. The young maggots begin to feed about 

 the cherry pit, and the flesh of an infested cherry 

 OR may be separated from the pit very easily, which 



yj can not be done with a cherry that is not infested. 



1 1 This feeding may be done before there are any 



fcjj outward signs of infestation, and often before 



the maggots are large enough to be seen easily. 

 Later on the cherry begins to shrivel on one side, 

 the flesh is found to be more or less decayed, and 

 smaU holes appear in the skin. At this stage the 

 fly. Five times natural white, nearly full-grown maggot may readily be 

 Slze " found in the fruit ; usually there is only one, but 



sometimes two or more. The maggots are more easily seen in the 

 dark-meated varieties of cherries such as the Lambert and the Late 

 Duke, and the impression that white cherries are not seriously infested 

 may be gained. However, careful examinations have shown that the 

 white cherries are often infested just as much as the black ones. The 

 infestation at times amounts to 75 to 90 percent of the crop. This 

 insect is a native of the Eastern States. 



LIFE HISTORY 



The maggots pass the winter in the soil, in small, hard, brown cases 

 Known as puparia. These are produced by the shrinking and drying 

 of the outer skin of the maggot. The flies (fig. 56) emerge from the 

 ground during June or July, and fly about in the sun for some days, 

 feeding on any moisture or honeydew that may be on the trees. 

 After a few days the females lay eggs in the cherries, piercing the skin 

 of the fruit with their ovipositors and depositing the eggs in the flesh. 

 The very small white maggots hatch in a week or less and immediately 

 begin to feed about the pit. Feeding continues for about 2 weeks, 

 and when fully grown the maggots, which are about one fourth inch 

 long, drop to the ground and form their purparia a few inches beneath 

 the surface. They remain there until the following spring. 



