462 



THE TROPICAL AGRICULTURIST. 



[December i, 1884. 



It occurs to us to " tag on " a general observation or 

 two. Fruit farming has been recommended as a remedy 

 for agricultural distress. Failing the possibility of growing 

 a paying crop of wheat, the- cereal farmer is advised to 

 turn his attention to raising fruit. Fruit farming is not a 

 pursuit in which success can be attained at haphazard. It 

 requires knowledge, patience, and capital, and the man 

 whose experience has been confined to the production of 

 grain, grass, and roots should realise the fact that, before 

 he can hope to replenish his depleted coffers by fruit 

 farming, he has got to learn a new business — nothing more 

 or less. — J. H. — Field. 



NAPHTHALINE AS AN INSECTICIDE, ETC. 



HY DH. THOMAS TAYLOK, 



Microscopist of the V. S. Department of Agriculture. 



About eleven years ago I had occasion to use large 

 quantities of the dead oil of tar for commercial purposes. 

 On removing the dead oil from the barrels I usually found 

 a large quantity of solid matter deposited in them; it 

 proved to be crude naphtaliue which had precipitated from 

 the " dead oil " on its cooling in the barrels. 



Incidentally several bushels of the naphthaline were placed 

 in an outshed and remained there undisturbed for a year, 

 when I observed that its odor was in no way diminished. 

 Being a coal-tar product, it occurred to me that it might 

 be of service as an insecticide, and to that end I instituted 

 a series of experiments with it on insects. I found that 

 it had the power of producing a state of asphyxia. I also 

 observed that different insects as well as the higher grades 

 of animals were unequally affected. The winged phylloxera 

 when immersed in the gas of this substance die almost 

 instantly, while a full-grown potato bug under the same 

 conditions would turn on its back and lie in that position 

 for a week, manifesting life only by a slight movement of 

 its limbs. In about ten days it dies ; if not coufiued for 

 too long a period, it recovers, and seems none the worse 

 for the treatment. Their larva are quickly destroyed when 

 the moistened powder of naphthaline is sprinkled on their 

 bodies. The common ant will nut cross over powdered 

 naphthaline if it can avoid it. 'While confined in a jar 

 containing a sprinkling of naphthaline they move about 

 rapidly for a short period, but invariably under such con- 

 ditions cast off their wings, first the right wing followed 

 by the left in quick succession, and shortly afterwards 

 roll on their backs and die if kept in the gas. Termites, 

 which prove so destructive to timber in buildings, are 

 much more easily affected by the gas than is the com- 

 mon ant. The common house fly seems quite spirited for 

 a few minutes, but ultimately turns on its back, becom- 

 ing asphyxiated; but a fly may be experimented with a 

 great many times without apparent injury by exposing it 

 to fresh air and odor of naphthaline alternately, while if 

 confined in the odor for too long a period it will die. 

 SThe common large blue fly (Musca Calephora) if a female 

 and pregnant invariably aborts when asphyxiated with the 

 odors. This fact may be of some importance physiologically. 

 After aborting the fly seems as lively as if it had not been 

 subjected to the influence of the gas, and as if no change 

 in its condition hud occurred. Honey bees and wasps are 

 affected in the same manner as house flies. Honey bees 

 in the hive may be anesthetized by placing about an 

 ounce of the pure white powder of naphthaline on the floor 

 of the hive, and carefully watching the effects of tbe 

 naphthaline on them when the bees are asleep ; the hive 

 may be uncovered and moths and honey removed. 



If a small portion of naphthaline is placed in the holes 

 of rats and mice they quickly vacate them and will not 

 return until the odor of the gas has disappeared. Frogs, 

 youug and old, become asphyxiated in this gas, and die only 

 when kept loug under its influence, although I have sceu 

 a young frog remain torpid under its influence for a period 

 of twelve hours, afterwards recovering from the stupor 

 apparently in a healthy condition. 



Several of the European governments have prohibited by 

 enactment the importation into their dominions of plants, 

 cuttings, bulbs, etc., from any country or district where 

 the phylloxera of the grape-vine is found, with the new 

 of preventing any further introduction of that insect into 

 their vine-growing districts. I made the suggestion several 



years ago that a few grains of naphthaline be placed in 

 small packages containing cuttings, bulbs intended for ex- 

 portation ; its odors would destroy nearly every descrip- 

 tion of insect present without injury to the plants. 



Great loss is sustained by farmers through theintroduc- 

 tiou of a variety of insects into the United States from 

 abroad through the medium of grain. In many cases this 

 might be easily prevented by simply placing a small bag 

 containing an ounce or so of naphthaline powder within 

 the packages, as already mentioned, before shipment. By 

 coufiuiug the naphthaliue in bags the odor will permeate 

 the entire sack of grain, and when desired the naphthaline 

 bag with its contents could be easily removed. This might 

 be useful, especially when the grain is intended for seed 

 purposes. About six years ago a sack of superior sorghum 

 seed had been bought for distribution by the Agricultural 

 Department. While it was in the seed-room, one of the 

 employees heard sounds proceeding from the sack ; on my 

 attention being called to it, I examined the seed and found it 

 alive with minute beetles, which accounted for the sound. I 

 placed a pint of these seeds into a quart bottle, and com- 

 bined with them a small portion of pure naphthaline. 

 Within au hour the sound ceased, and upon inspection 

 the insects were found to be destroyed. These seeds were 

 retained in the jar for a period of two years, and were 

 planted (by Mr. Wm. Saunders, iu charge of the propagating 

 garden of the Agricultural Department) to test them. 

 They germinated and grew, thus showing that the germ 

 of the seed was uninjured. The odor of the naphthaline 

 in the bottle which contained the sorghum seed was as 

 strong as when first applied to it. 



Although naphthaline has many practical uses, it has its 

 disadvantages. The direct rays of the sun falling on it in 

 exposed places caused it to evaporate, aud thus quickly 

 destroy its usefulness. 



In applying it on open ground, insects, such as crickets 

 grasshoppers, and roaches, will simply avoid it, but when 

 put iu the ground near the roots of plants or trees it 

 will have a beneficial effect, as the odors will drive away 

 all insects, or destroy them should they remain. 



When combined with water it acts more quickly on the 

 larva of insects than in the dry state. Worms, caterpillars, 

 and even roaches and the larva of the potato bug, evince 

 pain when the solution comes in contact with the tender 

 parts of their bodies. 



Large beetles resist its effects for several days. I have 

 observed a black species of roach survive, while the com- 

 mon brown species died under the same treatment. One 

 of the gardeners of the Department of Agriculture dis- 

 covered one evening that a beetle was at work gnawing the 

 leaves of one of his rose bushes. On looking around he 

 found that many of his bushes had been destroyed. This 

 led him to dig up the ground around the bushesi with the 

 hope that the beetles would be found, and to his gratific- 

 ation and surprise he found about fifty full-grown beetles, 

 measuring about an inch in length and nearly one-half 

 inch in diameter. I procured several of these beetles alive, 

 and subjected them to the orders of naphthaline for a 

 reasonable time without producing stupor. Finding it was 

 not likely that naphthaline coidd be successfully used as an 

 agent for their destruction, it occurred to me that a still 

 stronger chemical might give more satisfactory results. For 

 this purpose I used labarax solution (chlorinated soda.) In 

 t'.lis solution chlorine exists iu the free state, which is very 

 offensive to insects. 



I put a small portion of the labarax solution in an ounce 

 vial, and placed it under a receiver, together with three full- 

 grown rose beetles. The free, chlorine issuing from the solu- 

 tion quickly filled the receiver, when the beetles began to 

 move about rapidly. "Within a few minutes it was evident 

 that they were very much affected by the chlorine. In a 

 short time they rolled over on their backs and died. For some 

 purposes, therefore, the labarax solution might be employed 

 with better effect than naphthaline. Lut it should be observed 

 that delicate roots are quickly destroyed by chlorine. 



Several years ago I made a number of experiments on 

 plants growing in the hot-house of the Department in the 

 presence of Mr. Wm. Saunders. Observing a large banana 

 plant iufested with ants, I spriukled pure naphthaline on 

 the ground around the plant. The ants, which were descend- 

 ing in thousands to the ground, retraced their march on dis- 

 covering the naphthaline odor. Higher up on the banana 



