iV 
ing farmers by furnishing them oil for use in hopperdozers. The 
furnishing of free oil, however, is too great a tax upon the slender 
resources of the State Entomologist, and cannot be continued unless 
some more material financial aid is granted by the state. It has 
been suggested that a grasshopper emergency fund be created, and 
kept upon the State Auditor’s books for use in times of crisis. The 
trouble has come, in every case, from the existence in the neighbor- 
hood of large tracts of unused or reverted land, held by residents 
or non-residents, who either cannot or will not cultivate the same. 
The subject of grasshoppers, and the need of a more stringent grass- 
hopper law is discussed elsewhere in this report. The greatest 
damage which came under our observation occurred in Wilkin 
County, though Polk, Clay, Norman and other counties also suf- 
fered.) See page 10; 
Cutworms have been so abundant and injurious during the 
spring of 1910 that we have made them the subject of our colored 
plate. Later in the season the wheat head army worm, Heliophila 
diffusa, appeared in enormous numbers in about thirty different 
localities, and not only destroyed the seed of timothy, but injured 
this crop for hay, and in many cases marched to neighboring crops, 
causing wide-spread havoc. This pest, which is very rarely trouble- 
some, originated this year in Minnesota in timothy fields which had 
been allowed to lie too long unplowed. The army worm cited has 
been so injurious that it is made the subject of a special article in 
this report. See pages 1 and 4 and figures 1, 2 and 3 on colored 
plate. 
The annual visitation of the different kinds of grain lice was in 
evidence in 1909, not resulting, however, in any serious injury. 
No complaints have reached us of the Corn Root Worm which, 
however, 1s so abundant and injurious in Iowa that Professor 
Holden, of Ames, Iowa, reports that the 1910 corn crop of that 
state was damaged to the extent of $20,000,000. 
Shade trees have suffered both in 1g09 and 1910 from the pests 
common to them, and the year just closing is noteworthy on account 
of the quite wide-spread destruction of some of our finest city trees. 
Elms have been killed by the elm tree borer, and maples attacked 
in many cases and ruined by one or more species of Buprestid 
beetles which affect such trees. Both in 1909 and 1910 the Oak 
Pruner, the Fall Web Worm, the White-marked Tussock Moth, 
the Locust Borer, Bronze Birch Borer, Birch Leaf Skeletonizer, 
and Leaf Folders have been in evidence. (See page 103.) 
