16 MONTANA EXPERIMENT STATION BULLETIN 484 



was in the southern area and the other in the northern area of 

 the east shore of Flathead Lake. 



One orchard was sprayed with two applications of parathion 

 and one application of tetraethyl pyrophosphate. Individual 

 counts of 10,136 cherries showed no fruit fly infestation. 



The other orchard was dusted with lead arsenate and sulphur. 

 Individual counts of 7,243 cherries showed 30 fruit fly infested 

 cherries. 



A survey to determine the incidence of black cherry fruit fly 

 in bitter cherry, a native wild cherry, was conducted. Individual 

 counts of 5,016 fruits were made with negative results. 



RUST MITE (Phyllocoptes sp.) 



Populations of rust mites in the sweet and sour cherry trees 

 of western Montana were below economic levels in 1951 and 1952. 



PEAR SLUG (Caliroa cerasi) 

 Light to moderate infestations of pear slugs occurred in many 

 commercial and home orchards throughout western Montana dur- 

 ing the first year of the biennium. Reports indicate that this in- 

 sect pest of stone fruits was even more prevalent and caused more 

 extensive damage in 1952. Post-harvest toxaphene sprays were 

 used to combat this pest. 



BLACK CHERRY APHID {Myzus cerasi) 

 No reports of black cherry aphid infestations were received in 

 1951. In 1952 moderate to severe infestations occurred in the sweet 

 and sour cherry growing areas of Ravalli and Lake counties. Early 

 spring delayed dormant oil sprays will control this pest. 



CODLING MOTH (Carpocapsa pomonella) 

 No unusual outbreaks of codling moth were reported or ob- 

 served during the biennium. Reports and inquiries indicate that 

 normal infestations occurred in orchards and back yard plantings 

 where preventative control measures with DDT sprays were not 

 practiced. 



APPLE APHID (Aphis pomi) 

 No reports of apple aphid infestations were received in 1951. 

 Generally moderate to severe infestations occurred in apple orch- 

 ards throughout most of western Montana in 1952. 



WOOLLY ELM APHID (Eriosoma americanum) 



Woolly elm aphids were abnormally numerous over most of 

 the state in 1951, inflicting damage to elm and apple trees. Several 

 reports of infestations in western Montana orchards were received 

 in 1952. 



