500 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



But the great majority of planters cannot wait for the disappear- 

 ance of the pest, and have to resort to other defensive means. Vari- 

 ous external applications have been used to this effect: Decoctions of 

 Alder leaves. Tobacco, Pennyroyal, and other herbs, have been tried 

 with a view of preventing gnats from biting mules while at work; 

 but all of them have proven ineft'ective. At a time when small 

 swarms of Turkey Gnats were tormenting mules plowing in the field 

 one side of the animal was moistened by Mr. Lugger with various 

 insecticides, while the other side was not protected at all. By follow- 

 ing the animal and watching the gnats it was soon observed that any 

 offensive-smelling substance would drive the gnats from the pro- 

 tected side to the unprotected one. Kerosene emulsion, pyrethrum 

 powder suspended in vrater, diluted carbon-bisuli^hide, and dissolved 

 tobacco-soap were o.ll used in turn, and all seemed to produce the 

 same effect. Several times the whole animal was carefully sponged 

 with the one or the other of the above substances. For a time the 

 gnats would not settle upon the animal; but in the course of two 

 hours the beneficial effect of these insecticides was gone, and the in- 

 sects were no longer kept away. 



Experience shows that the best preventive is grease of various 

 kinds. The following kinds are the most important: Cotton-seed 

 oil alone, or mixed with tar, fish oil, gnat oil; a combination of stink- 

 ing oils alone, or mixed with tar or kerosene oil, crude coal oil, kero- 

 sene oil, kerosene oil mixed with axle-grease, and others. To be 

 effective, the grease must be used at least twice during the day, be- 

 cause as soon as its offensive odor disappears it becomes inoperative. 

 All such applications are of no advantage, however, on stock running 

 at large. Gnat oil is very extensively used, but it is like the rest of 

 the remedies — very apt to remove the hair.* In fact, all these differ- 

 ent kinds of oil and grease are more or less injurious to the animals, 

 because a continued coating v/ith them weakens the system. 



The employes of the Hudson's Bay Company protect themselves 

 and their stock against the bites of the "Black Fly" by the use of oil 

 of tar, and as long experience has shown it to be a simple and easily 

 applied wash, we strongly recommend its use. A quantity of coal 

 tar is jjlaced in the bottom of a large sliallow receptacle of some sort, 

 and a small quantity of oil of tar, or oil of turpentine, or any similar 

 material, is stirred in. The receptacle is_ then filled with water, 

 , which is left standing for several days until well impregnated with 

 the odor. The animals to be protected are then washed with this 

 water as often as seems to be necessary. 



As long as stock in the infested region is suffered to run at large, 

 and is neither provided with shelter nor food during the winter 

 months, it will suffer severely from the gnats. Animals well cared 

 for can stand the attacks of the gnats far better, and do not perish as 

 readily. Ill-treated and unhealthy mules and those bruised and cut 

 are the first to die, and the prevailing opinion of intelligent planters 

 is to the effect that Avell-cared-for mules, if greased twice a day v/hen 

 working in the field, seldom die even v/hen attacked. 



* According to Messrs. Fahlen & KHeinschmidt, chemists, of Memphis, Temi., 

 "Gnat oil is any kind of stinking oil; it should not contain drying oils, such as 

 Oleum lini and O. gosr,ypiV They use fish oil, and to increase its perfiime add 01. 

 animale foetidimi, 4 ounces to 10 gallons. But since fish oil costs 50 to 75 cents per 

 gallon, some mix it with crude petroleum; this addition, however, has the tendency 

 to kill the hair roots. 01. hedeomce (pennyroyal) is too costly, and therefore not 

 frequently used. Fish oil and 01. animale faetiduvi have given the best satisfaction. 



