INJURIOUS INSECTS OF 1905 IN MINNESOTA. 85 



fields until too late to prevent it. I have little clonbt that next 

 season, forewarned as we are, a repetition of this can be prevented. 



Early in the summer various species of cutworms were reported 

 bad in certain sections, flax-growing districts being perhaps the 

 worst sufferers. No specimens reached us with the complaints. In 

 June many inquiries were received regarding galls on plums. This 

 trouble was caused by a small mite known as Eriophyes padi Nal. It 

 has been troublesome before this date, being reported from Minnesota 

 in 1884. The cottony maple scale (Pulvinaria imiumerabilis Rathv.) 

 has been again a serious pest. The stalk borer (Papaipema nitela 

 Guen.) was again destructive, as was the corn-ear worm {Heliothis 

 obsoleta Fab.). A serious report of this pest reached us from Can- 

 non Falls, where " every other ear " was said to be infested. We 

 have had our usual quota of green cabbage worms, potato beetles, 

 and insects affecting squashes and melons. Potato beetles were re- 

 ported as being especially bad in the northern part of the Red River 

 Valley. The white grub, larva of Lachnosterna sp., has ravaged 

 lawns to a marked extent, its injuries being particularly noticeable 

 in cemeteries and like situations, where large tracts of grass make 

 it a difficult pest to conquer. In the course of our experiments we 

 discovered that the grub could stand immersion in a very strong 

 tobacco solution for several hours without serious results, apparently. 

 Hellebore was used in various ways without success. We have in 

 mind two preventive measures, which we shall test next season if 

 opportunity offers. 



Bruchophagus funebris How. was reared in quantities from crim- 

 son clover in July. Varieties of thistles, among them the Canada 

 thistle, were noticeably preyed upon by the larva? of Vanessa cardui L. 

 and many of these weeds were killed thereby. While abundant, these 

 caterpillars were not sufficiently numerous, of course, to eradicate 

 thistles, and, it must be confessed, also turned their attention to gar- 

 den plants — hollyhock, Calendula, etc. 



Mention has been made above of a troublesome gall-producing mite 

 on the leaves of plum. We have to report also, in this connection, 

 cecidomyiid gall makers again injuring leaves of soft maple and box- 

 elder; and the cockscomb gall locally abundant on leaves of white 

 elm. In one county we secured specimens of the peculiar globe-like 

 galls on red elms, caused by Pemphigus ulmifusus Walsh. The plum 

 curculio (C onotrachelus nenuphar Hbst.) made its appearance felt on 

 apples, as well as plums, and the New York weevil (Ithycerus nove- 

 boracensis Forst.), working on fruit trees, was complained of in some 

 sections. A lepidopterous borer (Podosesia syringce Harr.) attacked 

 young ash trees near Adelaide, so weakening their trunks as to cause 

 them to be broken down by the wind. A green sawfly larva worked 



