585 



CooLEv (R. A.). 18th Annual Report of the State Entomologist o! 

 Montana. — -Montana Agric. Expt. Sta., Bozeman, Bull. 139, 

 January 1921, 16 pp. [Received 10th October 1921.] 



Grasshoppers have been unusually prevalent in Montana during the 

 last few years [R.A.E., A, vii, 140, 141]. A map accompanying the 

 present report shows the infested areas. The species chiefly concerned 

 in 1920 differed from those most prevalent in 1919 [R. A.E., A, ix, 21] ; 

 they were Camnida pellucida, Melanopliis atlantis and M. bivittatus. 

 The earliest reports were of Siirapleura decttssata and Hippiscus 

 pardalimis, but these did not become sufficiently numerous to be 

 seriously injurious. Attention is being given to improving the arsenic 

 bran mash used against grasshoppers and reducing its cost. Amyl 

 acetate (known as " banana oil ") can be used as a substitute for 

 ground lemons or oranges, and reduces both the expense and the 

 labour involved. 



The pale western cutworm [Porosagrotis orthogonia] is one of the 

 most injurious insects in Montana. A table shows the percentage of 

 sown areas ruined by it in various localities, the total loss being reckoned 

 at about £600,000 for 1920. The work in connection with this insect 

 has been recorded elsewhere. [See preceding paper.] 



Tortrix (Archips) argyrospila (fruit-tree leaf-roller) is injurious to 

 apple trees in the Bitter Root Valley. The eggs are laid on the bark 

 of the trees during July and hatch in early spring, just as the leaf 

 buds are unfolding. The young larvae burrow among the tender 

 leaf buds, and as the leaves expand they web them together and 

 remain hidden. Complete defoliation frequently results, with corres- 

 ponding heavy loss in the fruit crop. The use of miscible oils before 

 the buds appear is recommended. Experiments in this connection 

 are being conducted. The alfalfa weevil [ Hypera variabilis] is spreading 

 gradually over the neighbouring States, and may be already present 

 in Montana ; a careful watch should be kept for its appearance. 

 Loxostege sticticalis (sugar-beet webworm) has been widely distributed 

 in Montana for several years, but is seldom of great importance ; 

 it is hoped that it will disappear before long owing to the action of 

 parasites. 



Minor pests in 1920 were Eriophyes pyri, Pgst. (pear-leaf blister 

 mite) ; thrips; Orthoptera, Steiroxys triUneata, Thom., Stenopclmatus 

 spp., and Brachystola magna, Gir. ; Rhynchota, Blissiis leucopterus. 

 Say (chinch bug), Myziis ribis, L. (currant aphis), Aphis corni- 

 foliae, Fitch (sunflower aphis), and Pemphigus beiae, Doane (sugar- 

 beet root-louse) ; Lepidoptera, Pieris [Pontia) rapae, L. (imported 

 cabbage worm), Pyrameis ( Vanessa) car did, L., on cultivated sun- 

 flowers, Plutella maculipennis (diamond-backed cabbage moth), 

 Cydia pomonella (codling moth), Telea polyphemus, Cram., Ufens 

 plicatus, Grote, and another Noctuid, believed to be Onychagrotis 

 rileyana, Morr., damaging the bark of cotton wood trees ; Diptera, 

 Hylemyia cerealis, Gill (western wheat-stem maggot), in spring wheat; 

 Coleoptera, Leptinotarsa decemlineata, Say (Colorado potato beetle), 

 Chrysomela exclamationis, F., on sunflowers, Cantharis niittalli, Sa^' 

 (blister beetle), Elaterid wireworms, Curculionids, and an unrecognised 

 strawberry crown-borer ; Hymenoptera, Bruchophagus funebris. How., 

 damaging lucerne seed, and rare individuals of Urocerus flavicornis, 

 F. (horn-tail). 



Sarcophaga kellyi, Aldr., which is the principal natural enemy of 

 grasshoppers, was also recorded. 



