BOARD OF HORTICÜLTURE 107 



THE CHERRY FRUIT FLY 



(Rhasoletis cingulata Loew) 

 By. A. L. Lovett, Entomologist, Oregon Agrieultural Experiment Station 



Numerous reports liave been received at the Station during the past four 

 j'ears of serious injury to ripe cherries by the cherry maggot. This insect has been 

 present in Oregon since about 1000. In an occasional season fUiring this period 

 late cherries have been heavily infested. It would appear. however, that the 

 infestation is liecoming more widely spread and of more frequent occurrence ; 

 that all medinm and late varieties of cherries are frequently seriously Injured, 

 and that the Status of the maggot as a pest of importance is increasing. 



Affected cherries generally escape detection until the fruit is mature. Soon 

 after picking. or where the ripe fruit is allowed to remain on the tree for a short 

 time, the side of the affected cherry turns Iirown and shrivels, and small holes 

 appear in the skin. An examination of the interior of the fruit reveals the fleshy 

 white maggot in the decaying cherry pulp. 



Deseription of the Fruit Fly 



The larva of the cherry fruit fly is white or waxy yellow in color, slightly 

 more than one-fourth inch long. It is a typical maggot form, blunt behind and 

 tapering to a point at the head end. 



The adult is a two-winged fly about two-thirds the size of the common house 

 fly. The body is dark, the head and legs yellow. The most distinguishing mark 

 is the conspicuous dark crossbands on the wings, figure 1. 



Life History 



The adult flies make their appearance in the orchard about the time the 

 medium late varieties of cherries begin to show color. The date of their appear- 

 ance will vary \\ith the season but will approximate June 8 to June 18. The 

 flies "sport" about on the foliage for a few days lapping up droplets of moisture 

 or honey dew. After a period of about ten days. egg laying begins. The eggs are 

 deposited under the surface of the skin of the fruit. These eggs hatch in from 

 five to seven days, and the young maggots attack and tunnel through the pulp 

 of the fruit. The time the maggot will spend within the fruit depends largely 

 upon the degree of ripeness l)ut will average about two weeks. 



The maggots mature during late July, leave the fruit and drop to the ground. 

 They tunnel down a few inches into the soll and transform to small reddish 

 brown capsule-like puparia. Here they remain until the following spring, to 

 emerge again as adult flies. 



Injurj^ 



Late Duke and Lambert cherries are most seriously infested. Where seedling 

 trees occur in or adjacent to the orchard, they usually afford a lireeding place 

 for the maggots, as they tend to ripen later and to hold the ripe fruit longer. In 

 seasons when the ripeuing period for cherries is unduly prolonged, as in 1918, 

 the general infestation of all medium and late varieties of cherries is to be 

 expected. Royal Anns were very heavily attacked in 1918, some growers reporting 

 an 80 per cent infestation. It is reasonable to assume, and field observations 

 substantiate the theory. that infestation of the earlier white meated varieties is 

 much more common than supposed. The maggots frequently have not assumed 

 any considerable size at picking time and are rather inconspicuous in the white 

 pulp and escape detection. 



Poison Spray Bait 



The use of sweetened poison sprays as a bait for the adults of fruit flies has 

 been recommended for years. This treatment has been found very successful for 



