HOSTS, ADULT EMERGENCE, AND DISTRIBUTION OF THE APPLE MAGGOT (DIPTERA, TEPHRITIDAE) IN UTAH

The apple maggot, Rhagoletis pomonella (Walsh), in Utah was reared fro m field infested apricot (Prunus armeniaca L.), chokecherry (Prunus vi rginiana L.), crabapple (Malus spp.), mahaleb (Prunus mahaleb L.), pyr acantha (Pyracantha coccinea Roemer), ornamental hawthorn (Crataegus m onogyna Jacquin and C. mollis Scheele), plum (Prunus americana Marshal l), river hawthorn (C douglasii Lindley), sweet cherry (Prunus avium L .), and tart cherry (Prunus cerasus L.) in Utah. Using 1 Mar as a star ting date and an 8-degrees-C lower threshold, 50% emergence was as ear ly as 1537 degree-days in cherry (both sweet and tart) to as late as 3 773 degree-days in pyracantha. The apple maggot has been detected in m ost areas where river hawthorn grows in Utah, and in all major fruit g rowing areas, except in Washington and Wayne Counties.