TWENTY-SIXTH REPORT OF STATE ENTOMOLOGIST 31 



during even years. In 1933 many maggots were reported, in 

 1934 very few flies or maggots were found, in 1935 quite a num- 

 ber of flies were taken and many maggots found, then again in 

 1936 fly and maggot populations were very low. It is safe to 

 predict that in 1937 cherry fruit flies will be numerous around 

 sour and wild cherries, but not in sweet varieties as the new 

 trees will not be bearing. 



A golden opportunity is afforded during the next three sea- 

 sons to practically eliminate the cherry fruit fly as a pest of the 

 Flathead cherry industry before the sweet cherry trees come 

 into bearing. This can be accomplished, first, by eradicating all 

 wild pin cherry trees near orchards, or spraying them, and sec- 

 ond, by spraying all sour cherry trees. Tests during 1934, 1935, 

 and 1936 have shown the efficiency of lead arsenate spray in 

 reducing infestations. Lead arsenate Vz pound in 10 gallons of 

 water sprayed in coarse drops with low pressure about one 

 quart per tree is the recommended practice. This is usually 

 applied twice, a week apart, the first when the fruit is just 

 showing color. The exact time depends on the appearance of Lhe 

 flies. 



The codling moth (Carpocapsa pomonella L.) is very trou- 

 blesome to Montana apple growers. Only one brood appears in 

 a single season but is spread over most of the season. This fac- 

 tor combined with rather indifferent spraying practices has 

 brought about severe apple losses in a number of places. A 

 carefully applied calyx spray followed by two cover sprays, 

 properly timed by the weather and emergence of moths, gives 

 satisfactory control. Lead arsenate 3 pounds to 100 gallons of 

 water plus 1 pound of spreader remains the standard formula. 

 This pest has not as yet reached all Montana apple trees. This 

 past season it was reported for the first time in Ronan. It is 

 especially bad in towns where back yard trees are not properly 

 sprayed. 



The Oyster-shell scale (Lepidosaphes ulmi L.j warrants con- 

 sideration as it is so prevalent on apple trees. Tests during 1935 

 and 1936 of various spray materials showed that liquid lime sul- 

 phur 28-32° Baume at 1 gallon to 8 gallons of water applied 

 as a dormant spray, gave the best control. Where apple scap 

 sprays of liquid lime sulphur 1 to 25 have been used regularly, 

 oyster-shell scale has not become a pest. Dry lime sulphur and 



