520 Journal of Agricultural Research voi. xii, no. s 



search has never located a single Hessian-fly egg on oats, although eggs 

 were found on many grasses. 



Since 1906 the relation between varieties and injury from Hessian 

 fly has received scant attention from investigators. Presumably the 

 work of Gossard and Houser has been accepted as disproof of the claims 

 of earlier observers that some varieties are resistant and others immune. 



Recently claims of immunity put forth by growers of certain varieties, 

 general observations by farmers in eastern and central Kansas that 

 hard wheats are more susceptible to injury than soft varieties, and re- 

 sults of experiments at the Kansas Agricultural Experiment Station 

 indicate that the subject is at least worthy of further investigation. 



Experiments have been outlined to determine (i) the relative infes- 

 tation and injury of different kinds, varieties, and strains of various 

 small grain, and (2) why certain kinds and varieties are resistant or 

 immune; or, if not, why they escape injury in some cases where others 

 are badly injured. This paper is concerned primarily with the first 



problem. 



EXPERIMENTAL DATA 



The data reported in this paper were collected from 87 kinds and 

 varieties of wheat (Triticum spp.), oats {Avena saliva), barley {Hordeum 

 spp.), rye (Secale cereale), emmer {Triticxim dicoccum), einkorn {Triti- 

 cum, monococcum) , and spelt (Triticum spelta), planted in the Agronomy 

 Nursery of the Kansas Agricultural Experiment Station in the fall of 

 1 91 6. The different varieties were planted each in a row 50 feet long and 

 10 inches apart. Two plantings were made on each of two dates, Septem- 

 ber 15 and October i. The soil was in excellent condition, moisture 

 was plentiful, germination was prompt, and growth was normal in every 

 respect. Hessian flies were numerous, and, as far as known, there was 

 ample opportunity for all varieties to become equally infested. In this 

 paper all varieties are tabulated in the order in which they were planted. 



Eight of the varieties tested were from Australia (rows i to 8, inclu- 

 sive, Table I), and had not been grown previously at Manhattan. The 

 spring varieties and about half of the soft winter varieties had been ob- 

 tained from various Experiment Stations in the United States in 1914 

 and had been grown at Manhattan for two years only before being in- 

 cluded in this experiment. All of the hard winter varieties and about 

 half of the soft winter varieties had been grown at Manhattan for several 

 years and were thoroughly acclimated. 



The relative number of eggs deposited on each variety was determined 

 by taking five consecutive plants from the west end of each row and 

 counting the total number of eggs on the leaves. The first count was 

 made at the time of maximum deposition, September 25. Subsequent 

 determinations were made for the early sown plots on October 2 and 7, 

 and for the late sown plot on October 14. The total number of plants 

 of each variety examined was 20. 



