TWENTY-SEVENTH REPORT OF STATE ENTOMOLOGIST 31 



WOOLLY ELM APHIS 



(Eriosoma americanum Riley) 



This plant louse has been extremely abundant in Montana 

 during the past 2 years. In some areas it has been the limiting 

 factor in the planting of American elms as shade trees. It at- 

 tacks the elms in the spring, curling and distorting the leaves, 

 and producing honey dew in quantities. In June a winged gen- 

 eration appears and the insects leave the elm leaves and go to 

 the roots of Juneberry. In the autumn they produce other winged 

 forms which migrate back to elms and deposit the overwinter- 

 ing eggs. On September 15th and 16th, 1938, the returning 

 migrants were clustering by the millions on the bark of elm 

 trees in Terry and Malta. 



Unless there are hosts other than the Juneberry, the elim- 

 ination of this alternate host should control this pest. Practically, 

 however, if not impossible, it certainly is not feasible to control 

 this insect in this manner. A thorough dormant spray consist- 

 ing of a 3 or 4 per cent oil emulsion has given fair results by 

 destroying the overwintering eggs. 



TOMATO WORM 



(Protoparce sexta Johanssen) 



It is probable that this pest of tomatoes has occurred in 

 Montana for some time. The first authentic records for Montana, 

 however, were obtained during the summer of 1938. One in- 

 dividual was received from Beaverhead County, and a number 

 of the worms were collected from tomato vines at Three Forks 

 on August 30, 1938. 



In gardens, hand picking is the best means of control. In 

 large plantings, dusting with lead arsenate at the rate of five 

 pounds per acre has been recommended in other parts of the 

 country. No dusting should be done for at least 10 days before 

 the tomatoes start to ripen. 



LITTLE EARWIG 



(Labia minor Linnaeus) 



This tiny earwig was first collected in Montana at Bozeman, 

 on May 31, 1914. It was not collected again until September 7, 

 1938, when one specimen was taken in the North Cottonwood 

 Canyon, Gallatin County, while sweeping for grasshoppers. 



