Article V. — The Effects of Kerosene and other Petroleum Oils 

 on the Viability and Growth of Zea mais. By John H. Written, 

 Ph.D. 



I. Introduction 



It has long been a custom among farmers to pour kerosene over 

 seed corn just previous to planting in order to protect it from being 

 injured or destroyed by squirrels, crows, or other pests. Until recent- 

 ly few or no careful observations had been made to determine whether 

 the treatment accomplished the purpose for which it was used or if 

 the effects on germination and subsequent growth were favorable or 

 otherwise. 



Lummis ('03), from a few preliminary experiments in field and 

 laboratory, reported a decided reduction in the percentage of germina- 

 tion and a very conspicuous injury to growth. Forbes ('08), seeking 

 a repellent particularly against the corn root-aphis, gave the kerosene 

 treatment a much more extensive trial. He found it very effective 

 in repelling the corn-field ant and consequently in controlling the aphis, 

 but he reports the frequent occurrence of "perplexing discrepancies" 

 in respect to the effects of the treatment on germination and growth. 

 His data show that in some instances corn was very markedly injured, 

 while in others a similar treatment produced no detrimental effect; 

 and that a brief treatment — thirty minutes' immersion — was more in- 

 jurious than one of twenty days. Having no explanation for such re- 

 sults and not desiring to enter into the analysis of a complex problem 

 of plant physiology. Professor Forbes abandoned the use of kerosene, 

 but he was free to admit that the scope of his investigations was too 

 limited to warrant general conclusions. 



Duggar and McCool ('09), issued a circular of information in- 

 tended especially for the constituency of the Cornell University Ex- 

 periment Station. In this report the authors made no pretension to 

 original investigation on the use of kerosene as a deterrent. They 

 laid particular stress on Professor Forbes's work and made their rec- 

 ommendations accordingly. 



Previous to the publication of the bulletin above cited there had 

 been some work done on the same subject under the direction of 

 Dr. Hottes in the laboratory of plant physiology at the University of 



A thesis submitted in partial fulfilment of the requirements for the 

 degree of Doctor of Philosophy in Botany in the Graduate School of the 

 University of Illinois, 1914, 



