Fifteenth Annual Report of the State 

 Entomologist of Montana 



INSECT PESTS OF 1917 

 THE MITES AND TICKS (ACARINA) 



Red Spider (Tetiunychios bimaculatus Harvey). Red spiders 

 did considerable damage to raspberries in various parts of the State. 

 The older growth was most seriously damaged and in many cases 

 was completely killed. The new growth was severely injured later 

 m the season. Control experiments were carried out with various 

 insecticides with considerable success. 



Pear-Leaf Blister Mite {Eriophyes pyri Pagnat). Pear-leaf blis- 

 ter-mite was reported as being injurious to apples in the Bitter Root 

 Valley and other localities in the western part of the State. Some 

 control experiments against this insect were carried on in conjunction 

 with the State Board of Horticulture. As had been previously dis- 

 covered, lime sulphur, sprayed when the buds were swelling, gave 

 satisfactory results. 



COCKROACHES AND GRASSHOPPERS (ORTHOPTERA) 



Cockroaches (Blatta gemianica Linn.). As usual, there were 

 a few inquiries concerning the eradication of cockroaches in houses 

 and business establishments. 



Grasshoppers (Melanoplus sp.). A grasshopper outbreak, cov- 

 ering the lower Bitter Root Valley, Missoula County, the Flathead 

 Indian Reservation, and Tobacco Plains was the most outstanding 

 feature of the year. Smaller outbreaks occurred in the Missouri 

 Valley between Three Forks and Townsend. Poisoned bran mash 

 was used earlier in the season, followed by grasshopper-catching 

 machines. The farmers caught many bushels of 'hoppers to use for 

 chicken feed. 



Shield-Backed Locust {Peranahrus scahydcollis Scud.). This 

 insect was found doing damage near Ronan, along with the Melano- 

 plus spp. in the general outbreak. It did not take the poisoned bran 

 mash as readily as did the Melanoplus. 



THRIPS (THYSANOPTERA) 



Grain Thrips {Anaphothrips striatus Osb.). The sterility of 



